Пример #1
0
def log_background_task(_, config, queue):
    """
    Use background task to update logger files using ray.tune `UnifiedLogger`
    """
    # Configure ray.tune loggers
    from ray.tune.logger import UnifiedLogger
    logger = UnifiedLogger(config=config,
                           logdir=config["logdir"],
                           loggers=config.get("loggers", None))
    logger.last_timestamp = logger.start_timestamp = time.time()

    # Wait for results
    results = queue.get()
    while results is not None:
        # Update ray.tune fields
        timestamp = results["timestamp"]
        results["config"] = config
        results["experiment_id"] = config["experiment_id"]
        results["experiment_tag"] = config["experiment_tag"]
        results["training_iteration"] = results.pop("epoch")
        results["neg_mean_loss"] = results["mean_loss"]
        results["timesteps_total"] = results.get("timestep", 0)
        results["timestamp"] = int(timestamp)
        results["date"] = datetime.fromtimestamp(timestamp).strftime(
            "%Y-%m-%d_%H-%M-%S")
        results["time_this_iter_s"] = timestamp - logger.last_timestamp
        results["time_total_s"] = timestamp - logger.start_timestamp
        logger.on_result(results)
        logger.last_timestamp = timestamp

        # Wait for next results
        results = queue.get()

    logger.flush()
    logger.close()
Пример #2
0
def run_trial(config):
    """
    Run a single trial configuration
    """
    # Configure ray.tune loggers
    from ray.tune.logger import UnifiedLogger
    logger = UnifiedLogger(config=config,
                           logdir=config["logdir"],
                           loggers=config.get("loggers", None))
    logger.last_timestamp = logger.start_timestamp = time.time()

    result = imagenet_run.run(config=config,
                              logger=partial(log_results, logger, config),
                              on_checkpoint=partial(save_checkpoint, config))

    logger.flush()
    logger.close()
    return result
Пример #3
0
class Trainable:
    """Abstract class for trainable models, functions, etc.

    A call to ``train()`` on a trainable will execute one logical iteration of
    training. As a rule of thumb, the execution time of one train call should
    be large enough to avoid overheads (i.e. more than a few seconds), but
    short enough to report progress periodically (i.e. at most a few minutes).

    Calling ``save()`` should save the training state of a trainable to disk,
    and ``restore(path)`` should restore a trainable to the given state.

    Generally you only need to implement ``setup``, ``step``,
    ``save_checkpoint``, and ``load_checkpoint`` when subclassing Trainable.

    Other implementation methods that may be helpful to override are
    ``log_result``, ``reset_config``, ``cleanup``, and ``_export_model``.

    When using Tune, Tune will convert this class into a Ray actor, which
    runs on a separate process. Tune will also change the current working
    directory of this process to ``self.logdir``.

    """

    def __init__(self, config=None, logger_creator=None):
        """Initialize an Trainable.

        Sets up logging and points ``self.logdir`` to a directory in which
        training outputs should be placed.

        Subclasses should prefer defining ``build()`` instead of overriding
        ``__init__()`` directly.

        Args:
            config (dict): Trainable-specific configuration data. By default
                will be saved as ``self.config``.
            logger_creator (func): Function that creates a ray.tune.Logger
                object. If unspecified, a default logger is created.
        """

        self._experiment_id = uuid.uuid4().hex
        self.config = config or {}
        trial_info = self.config.pop(TRIAL_INFO, None)

        self._result_logger = self._logdir = None
        self._create_logger(self.config, logger_creator)

        self._stdout_context = self._stdout_fp = self._stdout_stream = None
        self._stderr_context = self._stderr_fp = self._stderr_stream = None
        self._stderr_logging_handler = None

        stdout_file = self.config.pop(STDOUT_FILE, None)
        stderr_file = self.config.pop(STDERR_FILE, None)
        self._open_logfiles(stdout_file, stderr_file)

        self._iteration = 0
        self._time_total = 0.0
        self._timesteps_total = None
        self._episodes_total = None
        self._time_since_restore = 0.0
        self._timesteps_since_restore = 0
        self._iterations_since_restore = 0
        self._restored = False
        self._trial_info = trial_info

        start_time = time.time()
        self.setup(copy.deepcopy(self.config))
        setup_time = time.time() - start_time
        if setup_time > SETUP_TIME_THRESHOLD:
            logger.info("Trainable.setup took {:.3f} seconds. If your "
                        "trainable is slow to initialize, consider setting "
                        "reuse_actors=True to reduce actor creation "
                        "overheads.".format(setup_time))
        self._local_ip = self.get_current_ip()
        log_sys_usage = self.config.get("log_sys_usage", False)
        self._monitor = UtilMonitor(start=log_sys_usage)

    @classmethod
    def default_resource_request(cls, config):
        """Provides a static resource requirement for the given configuration.

        This can be overridden by sub-classes to set the correct trial resource
        allocation, so the user does not need to.

        .. code-block:: python

            @classmethod
            def default_resource_request(cls, config):
                return Resources(
                    cpu=0,
                    gpu=0,
                    extra_cpu=config["workers"],
                    extra_gpu=int(config["use_gpu"]) * config["workers"])

        Returns:
            Resources: A Resources object consumed by Tune for queueing.
        """
        return None

    @classmethod
    def resource_help(cls, config):
        """Returns a help string for configuring this trainable's resources.

        Args:
            config (dict): The Trainer's config dict.
        """
        return ""

    def get_current_ip(self):
        self._local_ip = ray.services.get_node_ip_address()
        return self._local_ip

    def train(self):
        """Runs one logical iteration of training.

        Calls ``step()`` internally. Subclasses should override ``step()``
        instead to return results.
        This method automatically fills the following fields in the result:

            `done` (bool): training is terminated. Filled only if not provided.

            `time_this_iter_s` (float): Time in seconds this iteration
            took to run. This may be overriden in order to override the
            system-computed time difference.

            `time_total_s` (float): Accumulated time in seconds for this
            entire experiment.

            `experiment_id` (str): Unique string identifier
            for this experiment. This id is preserved
            across checkpoint / restore calls.

            `training_iteration` (int): The index of this
            training iteration, e.g. call to train(). This is incremented
            after `step()` is called.

            `pid` (str): The pid of the training process.

            `date` (str): A formatted date of when the result was processed.

            `timestamp` (str): A UNIX timestamp of when the result
            was processed.

            `hostname` (str): Hostname of the machine hosting the training
            process.

            `node_ip` (str): Node ip of the machine hosting the training
            process.

        Returns:
            A dict that describes training progress.
        """
        start = time.time()
        result = self.step()
        assert isinstance(result, dict), "step() needs to return a dict."

        # We do not modify internal state nor update this result if duplicate.
        if RESULT_DUPLICATE in result:
            return result

        result = result.copy()

        self._iteration += 1
        self._iterations_since_restore += 1

        if result.get(TIME_THIS_ITER_S) is not None:
            time_this_iter = result[TIME_THIS_ITER_S]
        else:
            time_this_iter = time.time() - start
        self._time_total += time_this_iter
        self._time_since_restore += time_this_iter

        result.setdefault(DONE, False)

        # self._timesteps_total should only be tracked if increments provided
        if result.get(TIMESTEPS_THIS_ITER) is not None:
            if self._timesteps_total is None:
                self._timesteps_total = 0
            self._timesteps_total += result[TIMESTEPS_THIS_ITER]
            self._timesteps_since_restore += result[TIMESTEPS_THIS_ITER]

        # self._episodes_total should only be tracked if increments provided
        if result.get(EPISODES_THIS_ITER) is not None:
            if self._episodes_total is None:
                self._episodes_total = 0
            self._episodes_total += result[EPISODES_THIS_ITER]

        # self._timesteps_total should not override user-provided total
        result.setdefault(TIMESTEPS_TOTAL, self._timesteps_total)
        result.setdefault(EPISODES_TOTAL, self._episodes_total)
        result.setdefault(TRAINING_ITERATION, self._iteration)

        # Provides auto-filled neg_mean_loss for avoiding regressions
        if result.get("mean_loss"):
            result.setdefault("neg_mean_loss", -result["mean_loss"])

        now = datetime.today()
        result.update(
            experiment_id=self._experiment_id,
            date=now.strftime("%Y-%m-%d_%H-%M-%S"),
            timestamp=int(time.mktime(now.timetuple())),
            time_this_iter_s=time_this_iter,
            time_total_s=self._time_total,
            pid=os.getpid(),
            hostname=platform.node(),
            node_ip=self._local_ip,
            config=self.config,
            time_since_restore=self._time_since_restore,
            timesteps_since_restore=self._timesteps_since_restore,
            iterations_since_restore=self._iterations_since_restore)

        monitor_data = self._monitor.get_data()
        if monitor_data:
            result.update(monitor_data)

        self.log_result(result)

        if self._stdout_context:
            self._stdout_stream.flush()
        if self._stderr_context:
            self._stderr_stream.flush()

        return result

    def get_state(self):
        return {
            "experiment_id": self._experiment_id,
            "iteration": self._iteration,
            "timesteps_total": self._timesteps_total,
            "time_total": self._time_total,
            "episodes_total": self._episodes_total,
            "ray_version": ray.__version__,
        }

    def save(self, checkpoint_dir=None):
        """Saves the current model state to a checkpoint.

        Subclasses should override ``_save()`` instead to save state.
        This method dumps additional metadata alongside the saved path.

        Args:
            checkpoint_dir (str): Optional dir to place the checkpoint.

        Returns:
            str: Checkpoint path or prefix that may be passed to restore().
        """
        checkpoint_dir = TrainableUtil.make_checkpoint_dir(
            checkpoint_dir or self.logdir, index=self.iteration)
        checkpoint = self.save_checkpoint(checkpoint_dir)
        trainable_state = self.get_state()
        checkpoint_path = TrainableUtil.process_checkpoint(
            checkpoint,
            parent_dir=checkpoint_dir,
            trainable_state=trainable_state)
        return checkpoint_path

    def save_to_object(self):
        """Saves the current model state to a Python object.

        It also saves to disk but does not return the checkpoint path.

        Returns:
            Object holding checkpoint data.
        """
        tmpdir = tempfile.mkdtemp("save_to_object", dir=self.logdir)
        checkpoint_path = self.save(tmpdir)
        # Save all files in subtree and delete the tmpdir.
        obj = TrainableUtil.checkpoint_to_object(checkpoint_path)
        shutil.rmtree(tmpdir)
        return obj

    def restore(self, checkpoint_path):
        """Restores training state from a given model checkpoint.

        These checkpoints are returned from calls to save().

        Subclasses should override ``_restore()`` instead to restore state.
        This method restores additional metadata saved with the checkpoint.
        """
        with open(checkpoint_path + ".tune_metadata", "rb") as f:
            metadata = pickle.load(f)
        self._experiment_id = metadata["experiment_id"]
        self._iteration = metadata["iteration"]
        self._timesteps_total = metadata["timesteps_total"]
        self._time_total = metadata["time_total"]
        self._episodes_total = metadata["episodes_total"]
        saved_as_dict = metadata["saved_as_dict"]
        if saved_as_dict:
            with open(checkpoint_path, "rb") as loaded_state:
                checkpoint_dict = pickle.load(loaded_state)
            checkpoint_dict.update(tune_checkpoint_path=checkpoint_path)
            self.load_checkpoint(checkpoint_dict)
        else:
            self.load_checkpoint(checkpoint_path)
        self._time_since_restore = 0.0
        self._timesteps_since_restore = 0
        self._iterations_since_restore = 0
        self._restored = True
        logger.info("Restored on %s from checkpoint: %s",
                    self.get_current_ip(), checkpoint_path)
        state = {
            "_iteration": self._iteration,
            "_timesteps_total": self._timesteps_total,
            "_time_total": self._time_total,
            "_episodes_total": self._episodes_total,
        }
        logger.info("Current state after restoring: %s", state)

    def restore_from_object(self, obj):
        """Restores training state from a checkpoint object.

        These checkpoints are returned from calls to save_to_object().
        """
        tmpdir = tempfile.mkdtemp("restore_from_object", dir=self.logdir)
        checkpoint_path = TrainableUtil.create_from_pickle(obj, tmpdir)
        self.restore(checkpoint_path)
        shutil.rmtree(tmpdir)

    def delete_checkpoint(self, checkpoint_path):
        """Deletes local copy of checkpoint.

        Args:
            checkpoint_path (str): Path to checkpoint.
        """
        try:
            checkpoint_dir = TrainableUtil.find_checkpoint_dir(checkpoint_path)
        except FileNotFoundError:
            # The checkpoint won't exist locally if the
            # trial was rescheduled to another worker.
            logger.debug("Checkpoint not found during garbage collection.")
            return
        if os.path.exists(checkpoint_dir):
            shutil.rmtree(checkpoint_dir)

    def export_model(self, export_formats, export_dir=None):
        """Exports model based on export_formats.

        Subclasses should override _export_model() to actually
        export model to local directory.

        Args:
            export_formats (Union[list,str]): Format or list of (str) formats
                that should be exported.
            export_dir (str): Optional dir to place the exported model.
                Defaults to self.logdir.

        Returns:
            A dict that maps ExportFormats to successfully exported models.
        """
        if isinstance(export_formats, str):
            export_formats = [export_formats]
        export_dir = export_dir or self.logdir
        return self._export_model(export_formats, export_dir)

    def reset(self, new_config, logger_creator=None):
        """Resets trial for use with new config.

        Subclasses should override reset_config() to actually
        reset actor behavior for the new config."""
        self.config = new_config

        self._result_logger.flush()
        self._result_logger.close()

        self._create_logger(new_config.copy(), logger_creator)

        stdout_file = new_config.pop(STDOUT_FILE, None)
        stderr_file = new_config.pop(STDERR_FILE, None)

        self._close_logfiles()
        self._open_logfiles(stdout_file, stderr_file)

        return self.reset_config(new_config)

    def reset_config(self, new_config):
        """Resets configuration without restarting the trial.

        This method is optional, but can be implemented to speed up algorithms
        such as PBT, and to allow performance optimizations such as running
        experiments with reuse_actors=True.

        Args:
            new_config (dict): Updated hyperparameter configuration
                for the trainable.

        Returns:
            True if reset was successful else False.
        """
        return False

    def _create_logger(self, config, logger_creator=None):
        """Create logger from logger creator.

        Sets _logdir and _result_logger.
        """
        if logger_creator:
            self._result_logger = logger_creator(config)
            self._logdir = self._result_logger.logdir
        else:
            logdir_prefix = datetime.today().strftime("%Y-%m-%d_%H-%M-%S")
            ray.utils.try_to_create_directory(DEFAULT_RESULTS_DIR)
            self._logdir = tempfile.mkdtemp(
                prefix=logdir_prefix, dir=DEFAULT_RESULTS_DIR)
            self._result_logger = UnifiedLogger(
                config, self._logdir, loggers=None)

    def _open_logfiles(self, stdout_file, stderr_file):
        """Create loggers. Open stdout and stderr logfiles."""
        if stdout_file:
            stdout_path = os.path.expanduser(
                os.path.join(self._logdir, stdout_file))
            self._stdout_fp = open(stdout_path, "a+")
            self._stdout_stream = Tee(sys.stdout, self._stdout_fp)
            self._stdout_context = redirect_stdout(self._stdout_stream)
            self._stdout_context.__enter__()

        if stderr_file:
            stderr_path = os.path.expanduser(
                os.path.join(self._logdir, stderr_file))
            self._stderr_fp = open(stderr_path, "a+")
            self._stderr_stream = Tee(sys.stderr, self._stderr_fp)
            self._stderr_context = redirect_stderr(self._stderr_stream)
            self._stderr_context.__enter__()

            # Add logging handler to root ray logger
            formatter = logging.Formatter("[%(levelname)s %(asctime)s] "
                                          "%(filename)s: %(lineno)d  "
                                          "%(message)s")
            self._stderr_logging_handler = logging.StreamHandler(
                self._stderr_fp)
            self._stderr_logging_handler.setFormatter(formatter)
            ray.logger.addHandler(self._stderr_logging_handler)

    def _close_logfiles(self):
        """Close stdout and stderr logfiles."""
        if self._stderr_logging_handler:
            ray.logger.removeHandler(self._stderr_logging_handler)

        if self._stdout_context:
            self._stdout_stream.flush()
            self._stdout_context.__exit__(None, None, None)
            self._stdout_fp.close()
            self._stdout_context = None
        if self._stderr_context:
            self._stderr_stream.flush()
            self._stderr_context.__exit__(None, None, None)
            self._stderr_fp.close()
            self._stderr_context = None

    def stop(self):
        """Releases all resources used by this trainable.

        Calls ``Trainable.cleanup`` internally. Subclasses should override
        ``Trainable.cleanup`` for custom cleanup procedures.
        """
        self._result_logger.flush()
        self._result_logger.close()
        self.cleanup()

        self._close_logfiles()

    @property
    def logdir(self):
        """Directory of the results and checkpoints for this Trainable.

        Tune will automatically sync this folder with the driver if execution
        is distributed.

        Note that the current working directory will also be changed to this.

        """
        return os.path.join(self._logdir, "")

    @property
    def trial_name(self):
        """Trial name for the corresponding trial of this Trainable.

        This is not set if not using Tune.

        .. code-block:: python

            name = self.trial_name
        """
        if self._trial_info:
            return self._trial_info.trial_name
        else:
            return "default"

    @property
    def trial_id(self):
        """Trial ID for the corresponding trial of this Trainable.

        This is not set if not using Tune.

        .. code-block:: python

            trial_id = self.trial_id
        """
        if self._trial_info:
            return self._trial_info.trial_id
        else:
            return "default"

    @property
    def iteration(self):
        """Current training iteration.

        This value is automatically incremented every time `train()` is called
        and is automatically inserted into the training result dict.

        """
        return self._iteration

    @property
    def training_iteration(self):
        """Current training iteration (same as `self.iteration`).

        This value is automatically incremented every time `train()` is called
        and is automatically inserted into the training result dict.

        """
        return self._iteration

    def get_config(self):
        """Returns configuration passed in by Tune."""
        return self.config

    def step(self):
        """Subclasses should override this to implement train().

        The return value will be automatically passed to the loggers. Users
        can also return `tune.result.DONE` or `tune.result.SHOULD_CHECKPOINT`
        as a key to manually trigger termination or checkpointing of this
        trial. Note that manual checkpointing only works when subclassing
        Trainables.

        .. versionadded:: 0.8.7

        Returns:
            A dict that describes training progress.

        """
        result = self._train()

        if self._is_overriden("_train") and log_once("_train"):
            logger.warning(
                "Trainable._train is deprecated and will be removed in "
                "a future version of Ray. Override Trainable.step instead.")
        return result

    def _train(self):
        """This method is deprecated. Override 'Trainable.step' instead.

        .. versionchanged:: 0.8.7
        """
        raise NotImplementedError

    def save_checkpoint(self, tmp_checkpoint_dir):
        """Subclasses should override this to implement ``save()``.

        Warning:
            Do not rely on absolute paths in the implementation of
            ``Trainable.save_checkpoint`` and ``Trainable.load_checkpoint``.

        Use ``validate_save_restore`` to catch ``Trainable.save_checkpoint``/
        ``Trainable.load_checkpoint`` errors before execution.

        >>> from ray.tune.utils import validate_save_restore
        >>> validate_save_restore(MyTrainableClass)
        >>> validate_save_restore(MyTrainableClass, use_object_store=True)

        .. versionadded:: 0.8.7

        Args:
            tmp_checkpoint_dir (str): The directory where the checkpoint
                file must be stored. In a Tune run, if the trial is paused,
                the provided path may be temporary and moved.

        Returns:
            A dict or string. If string, the return value is expected to be
            prefixed by `tmp_checkpoint_dir`. If dict, the return value will
            be automatically serialized by Tune and
            passed to ``Trainable.load_checkpoint()``.

        Examples:
            >>> print(trainable1.save_checkpoint("/tmp/checkpoint_1"))
            "/tmp/checkpoint_1/my_checkpoint_file"
            >>> print(trainable2.save_checkpoint("/tmp/checkpoint_2"))
            {"some": "data"}

            >>> trainable.save_checkpoint("/tmp/bad_example")
            "/tmp/NEW_CHECKPOINT_PATH/my_checkpoint_file" # This will error.
        """
        checkpoint = self._save(tmp_checkpoint_dir)

        if self._is_overriden("_save") and log_once("_save"):
            logger.warning(
                "Trainable._save is deprecated and will be removed in a "
                "future version of Ray. Override "
                "Trainable.save_checkpoint instead.")
        return checkpoint

    def _save(self, tmp_checkpoint_dir):
        """This method is deprecated. Override 'save_checkpoint' instead.

        .. versionchanged:: 0.8.7
        """
        raise NotImplementedError

    def load_checkpoint(self, checkpoint):
        """Subclasses should override this to implement restore().

        Warning:
            In this method, do not rely on absolute paths. The absolute
            path of the checkpoint_dir used in ``Trainable.save_checkpoint``
            may be changed.

        If ``Trainable.save_checkpoint`` returned a prefixed string, the
        prefix of the checkpoint string returned by
        ``Trainable.save_checkpoint`` may be changed.
        This is because trial pausing depends on temporary directories.

        The directory structure under the checkpoint_dir provided to
        ``Trainable.save_checkpoint`` is preserved.

        See the example below.

        .. code-block:: python

            class Example(Trainable):
                def save_checkpoint(self, checkpoint_path):
                    print(checkpoint_path)
                    return os.path.join(checkpoint_path, "my/check/point")

                def load_checkpoint(self, checkpoint):
                    print(checkpoint)

            >>> trainer = Example()
            >>> obj = trainer.save_to_object()  # This is used when PAUSED.
            <logdir>/tmpc8k_c_6hsave_to_object/checkpoint_0/my/check/point
            >>> trainer.restore_from_object(obj)  # Note the different prefix.
            <logdir>/tmpb87b5axfrestore_from_object/checkpoint_0/my/check/point

        .. versionadded:: 0.8.7

        Args:
            checkpoint (str|dict): If dict, the return value is as
                returned by `save_checkpoint`. If a string, then it is
                a checkpoint path that may have a different prefix than that
                returned by `save_checkpoint`. The directory structure
                underneath the `checkpoint_dir` `save_checkpoint` is preserved.
        """
        self._restore(checkpoint)
        if self._is_overriden("_restore") and log_once("_restore"):
            logger.warning(
                "Trainable._restore is deprecated and will be removed in a "
                "future version of Ray. Override Trainable.load_checkpoint "
                "instead.")

    def _restore(self, checkpoint):
        """This method is deprecated. Override 'load_checkpoint' instead.

        .. versionchanged:: 0.8.7
        """
        raise NotImplementedError

    def setup(self, config):
        """Subclasses should override this for custom initialization.

        .. versionadded:: 0.8.7

        Args:
            config (dict): Hyperparameters and other configs given.
                Copy of `self.config`.
        """
        self._setup(config)
        if self._is_overriden("_setup") and log_once("_setup"):
            logger.warning(
                "Trainable._setup is deprecated and will be removed in "
                "a future version of Ray. Override Trainable.setup instead.")

    def _setup(self, config):
        """This method is deprecated. Override 'setup' instead.

        .. versionchanged:: 0.8.7
        """
        pass

    def log_result(self, result):
        """Subclasses can optionally override this to customize logging.

        The logging here is done on the worker process rather than
        the driver. You may want to turn off driver logging via the
        ``loggers`` parameter in ``tune.run`` when overriding this function.

        .. versionadded:: 0.8.7

        Args:
            result (dict): Training result returned by step().
        """
        self._log_result(result)
        if self._is_overriden("_log_result") and log_once("_log_result"):
            logger.warning(
                "Trainable._log_result is deprecated and will be removed in "
                "a future version of Ray. Override "
                "Trainable.log_result instead.")

    def _log_result(self, result):
        """This method is deprecated. Override 'log_result' instead.

        .. versionchanged:: 0.8.7
        """
        self._result_logger.on_result(result)

    def cleanup(self):
        """Subclasses should override this for any cleanup on stop.

        If any Ray actors are launched in the Trainable (i.e., with a RLlib
        trainer), be sure to kill the Ray actor process here.

        You can kill a Ray actor by calling `actor.__ray_terminate__.remote()`
        on the actor.

        .. versionadded:: 0.8.7
        """
        self._stop()
        if self._is_overriden("_stop") and log_once("trainable.cleanup"):
            logger.warning(
                "Trainable._stop is deprecated and will be removed in "
                "a future version of Ray. Override Trainable.cleanup instead.")

    def _stop(self):
        """This method is deprecated. Override 'cleanup' instead.

        .. versionchanged:: 0.8.7
        """
        pass

    def _export_model(self, export_formats, export_dir):
        """Subclasses should override this to export model.

        Args:
            export_formats (list): List of formats that should be exported.
            export_dir (str): Directory to place exported models.

        Return:
            A dict that maps ExportFormats to successfully exported models.
        """
        return {}

    def _is_overriden(self, key):
        return getattr(self, key).__code__ != getattr(Trainable, key).__code__
Пример #4
0
class Trial(object):
    """A trial object holds the state for one model training run.

    Trials are themselves managed by the TrialRunner class, which implements
    the event loop for submitting trial runs to a Ray cluster.

    Trials start in the PENDING state, and transition to RUNNING once started.
    On error it transitions to ERROR, otherwise TERMINATED on success.
    """

    PENDING = "PENDING"
    RUNNING = "RUNNING"
    PAUSED = "PAUSED"
    TERMINATED = "TERMINATED"
    ERROR = "ERROR"

    def __init__(self,
                 trainable_name,
                 config=None,
                 trial_id=None,
                 local_dir=DEFAULT_RESULTS_DIR,
                 experiment_tag="",
                 resources=None,
                 stopping_criterion=None,
                 checkpoint_freq=0,
                 checkpoint_at_end=False,
                 export_formats=None,
                 restore_path=None,
                 upload_dir=None,
                 trial_name_creator=None,
                 loggers=None,
                 sync_function=None,
                 max_failures=0):
        """Initialize a new trial.

        The args here take the same meaning as the command line flags defined
        in ray.tune.config_parser.
        """

        Trial._registration_check(trainable_name)
        # Trial config
        self.trainable_name = trainable_name
        self.config = config or {}
        self.local_dir = os.path.expanduser(local_dir)
        self.experiment_tag = experiment_tag
        self.resources = (
            resources
            or self._get_trainable_cls().default_resource_request(self.config))
        self.stopping_criterion = stopping_criterion or {}
        self.upload_dir = upload_dir
        self.loggers = loggers
        self.sync_function = sync_function
        validate_sync_function(sync_function)
        self.verbose = True
        self.max_failures = max_failures

        # Local trial state that is updated during the run
        self.last_result = {}
        self.last_update_time = -float("inf")
        self.checkpoint_freq = checkpoint_freq
        self.checkpoint_at_end = checkpoint_at_end
        self._checkpoint = Checkpoint(
            storage=Checkpoint.DISK, value=restore_path)
        self.export_formats = export_formats
        self.status = Trial.PENDING
        self.logdir = None
        self.runner = None
        self.result_logger = None
        self.last_debug = 0
        self.trial_id = Trial.generate_id() if trial_id is None else trial_id
        self.error_file = None
        self.num_failures = 0

        self.custom_trial_name = None

        # AutoML fields
        self.results = None
        self.best_result = None
        self.param_config = None
        self.extra_arg = None

        self._nonjson_fields = [
            "_checkpoint",
            "config",
            "loggers",
            "sync_function",
            "last_result",
            "results",
            "best_result",
            "param_config",
            "extra_arg",
        ]
        if trial_name_creator:
            self.custom_trial_name = trial_name_creator(self)

    @classmethod
    def _registration_check(cls, trainable_name):
        if not has_trainable(trainable_name):
            # Make sure rllib agents are registered
            from ray import rllib  # noqa: F401
            if not has_trainable(trainable_name):
                raise TuneError("Unknown trainable: " + trainable_name)

    @classmethod
    def generate_id(cls):
        return binary_to_hex(_random_string())[:8]

    def init_logger(self):
        """Init logger."""

        if not self.result_logger:
            if not os.path.exists(self.local_dir):
                os.makedirs(self.local_dir)
            if not self.logdir:
                self.logdir = tempfile.mkdtemp(
                    prefix="{}_{}".format(
                        str(self)[:MAX_LEN_IDENTIFIER], date_str()),
                    dir=self.local_dir)
            elif not os.path.exists(self.logdir):
                os.makedirs(self.logdir)

            self.result_logger = UnifiedLogger(
                self.config,
                self.logdir,
                upload_uri=self.upload_dir,
                loggers=self.loggers,
                sync_function=self.sync_function)

    def update_resources(self, cpu, gpu, **kwargs):
        """EXPERIMENTAL: Updates the resource requirements.

        Should only be called when the trial is not running.

        Raises:
            ValueError if trial status is running.
        """
        if self.status is Trial.RUNNING:
            raise ValueError("Cannot update resources while Trial is running.")
        self.resources = Resources(cpu, gpu, **kwargs)

    def sync_logger_to_new_location(self, worker_ip):
        """Updates the logger location.

        Also pushes logdir to worker_ip, allowing for cross-node recovery.
        """
        if self.result_logger:
            self.result_logger.sync_results_to_new_location(worker_ip)

    def close_logger(self):
        """Close logger."""

        if self.result_logger:
            self.result_logger.close()
            self.result_logger = None

    def write_error_log(self, error_msg):
        if error_msg and self.logdir:
            self.num_failures += 1  # may be moved to outer scope?
            error_file = os.path.join(self.logdir,
                                      "error_{}.txt".format(date_str()))
            with open(error_file, "w") as f:
                f.write(error_msg)
            self.error_file = error_file

    def should_stop(self, result):
        """Whether the given result meets this trial's stopping criteria."""

        if result.get(DONE):
            return True

        for criteria, stop_value in self.stopping_criterion.items():
            if criteria not in result:
                raise TuneError(
                    "Stopping criteria {} not provided in result {}.".format(
                        criteria, result))
            if result[criteria] >= stop_value:
                return True

        return False

    def should_checkpoint(self):
        """Whether this trial is due for checkpointing."""
        result = self.last_result or {}

        if result.get(DONE) and self.checkpoint_at_end:
            return True

        if self.checkpoint_freq:
            return result.get(TRAINING_ITERATION,
                              0) % self.checkpoint_freq == 0
        else:
            return False

    def progress_string(self):
        """Returns a progress message for printing out to the console."""

        if not self.last_result:
            return self._status_string()

        def location_string(hostname, pid):
            if hostname == os.uname()[1]:
                return 'pid={}'.format(pid)
            else:
                return '{} pid={}'.format(hostname, pid)

        pieces = [
            '{}'.format(self._status_string()), '[{}]'.format(
                self.resources.summary_string()), '[{}]'.format(
                    location_string(
                        self.last_result.get(HOSTNAME),
                        self.last_result.get(PID))), '{} s'.format(
                            int(self.last_result.get(TIME_TOTAL_S)))
        ]

        if self.last_result.get(TRAINING_ITERATION) is not None:
            pieces.append('{} iter'.format(
                self.last_result[TRAINING_ITERATION]))

        if self.last_result.get(TIMESTEPS_TOTAL) is not None:
            pieces.append('{} ts'.format(self.last_result[TIMESTEPS_TOTAL]))

        if self.last_result.get(EPISODE_REWARD_MEAN) is not None:
            pieces.append('{} rew'.format(
                format(self.last_result[EPISODE_REWARD_MEAN], '.3g')))

        if self.last_result.get(MEAN_LOSS) is not None:
            pieces.append('{} loss'.format(
                format(self.last_result[MEAN_LOSS], '.3g')))

        if self.last_result.get(MEAN_ACCURACY) is not None:
            pieces.append('{} acc'.format(
                format(self.last_result[MEAN_ACCURACY], '.3g')))

        return ', '.join(pieces)

    def _status_string(self):
        return "{}{}".format(
            self.status, ", {} failures: {}".format(self.num_failures,
                                                    self.error_file)
            if self.error_file else "")

    def has_checkpoint(self):
        return self._checkpoint.value is not None

    def clear_checkpoint(self):
        self._checkpoint.value = None

    def should_recover(self):
        """Returns whether the trial qualifies for restoring.

        This is if a checkpoint frequency is set and has not failed more than
        max_failures. This may return true even when there may not yet
        be a checkpoint.
        """
        return (self.checkpoint_freq > 0
                and (self.num_failures < self.max_failures
                     or self.max_failures < 0))

    def update_last_result(self, result, terminate=False):
        if terminate:
            result.update(done=True)
        if self.verbose and (terminate or time.time() - self.last_debug >
                             DEBUG_PRINT_INTERVAL):
            print("Result for {}:".format(self))
            print("  {}".format(pretty_print(result).replace("\n", "\n  ")))
            self.last_debug = time.time()
        self.last_result = result
        self.last_update_time = time.time()
        self.result_logger.on_result(self.last_result)

    def _get_trainable_cls(self):
        return ray.tune.registry._global_registry.get(
            ray.tune.registry.TRAINABLE_CLASS, self.trainable_name)

    def set_verbose(self, verbose):
        self.verbose = verbose

    def is_finished(self):
        return self.status in [Trial.TERMINATED, Trial.ERROR]

    def __repr__(self):
        return str(self)

    def __str__(self):
        """Combines ``env`` with ``trainable_name`` and ``experiment_tag``.

        Can be overriden with a custom string creator.
        """
        if self.custom_trial_name:
            return self.custom_trial_name

        if "env" in self.config:
            env = self.config["env"]
            if isinstance(env, type):
                env = env.__name__
            identifier = "{}_{}".format(self.trainable_name, env)
        else:
            identifier = self.trainable_name
        if self.experiment_tag:
            identifier += "_" + self.experiment_tag
        return identifier.replace("/", "_")

    def __getstate__(self):
        """Memento generator for Trial.

        Sets RUNNING trials to PENDING, and flushes the result logger.
        Note this can only occur if the trial holds a DISK checkpoint.
        """
        assert self._checkpoint.storage == Checkpoint.DISK, (
            "Checkpoint must not be in-memory.")
        state = self.__dict__.copy()
        state["resources"] = resources_to_json(self.resources)

        for key in self._nonjson_fields:
            state[key] = binary_to_hex(cloudpickle.dumps(state.get(key)))

        state["runner"] = None
        state["result_logger"] = None
        if self.result_logger:
            self.result_logger.flush()
            state["__logger_started__"] = True
        else:
            state["__logger_started__"] = False
        return copy.deepcopy(state)

    def __setstate__(self, state):
        logger_started = state.pop("__logger_started__")
        state["resources"] = json_to_resources(state["resources"])
        if state["status"] == Trial.RUNNING:
            state["status"] = Trial.PENDING
        for key in self._nonjson_fields:
            state[key] = cloudpickle.loads(hex_to_binary(state[key]))

        self.__dict__.update(state)
        Trial._registration_check(self.trainable_name)
        if logger_started:
            self.init_logger()
Пример #5
0
class Trial:
    """A trial object holds the state for one model training run.

    Trials are themselves managed by the TrialRunner class, which implements
    the event loop for submitting trial runs to a Ray cluster.

    Trials start in the PENDING state, and transition to RUNNING once started.
    On error it transitions to ERROR, otherwise TERMINATED on success.
    """

    PENDING = "PENDING"
    RUNNING = "RUNNING"
    PAUSED = "PAUSED"
    TERMINATED = "TERMINATED"
    ERROR = "ERROR"

    def __init__(self,
                 trainable_name,
                 config=None,
                 trial_id=None,
                 local_dir=DEFAULT_RESULTS_DIR,
                 evaluated_params=None,
                 experiment_tag="",
                 resources=None,
                 stopping_criterion=None,
                 remote_checkpoint_dir=None,
                 checkpoint_freq=0,
                 checkpoint_at_end=False,
                 sync_on_checkpoint=True,
                 keep_checkpoints_num=None,
                 checkpoint_score_attr=TRAINING_ITERATION,
                 export_formats=None,
                 restore_path=None,
                 trial_name_creator=None,
                 loggers=None,
                 sync_to_driver_fn=None,
                 max_failures=0):
        """Initialize a new trial.

        The args here take the same meaning as the command line flags defined
        in ray.tune.config_parser.
        """
        validate_trainable(trainable_name)
        # Trial config
        self.trainable_name = trainable_name
        self.trial_id = Trial.generate_id() if trial_id is None else trial_id
        self.config = config or {}
        self.local_dir = local_dir  # This remains unexpanded for syncing.

        #: Parameters that Tune varies across searches.
        self.evaluated_params = evaluated_params or {}
        self.experiment_tag = experiment_tag
        trainable_cls = self.get_trainable_cls()
        if trainable_cls and hasattr(trainable_cls,
                                     "default_resource_request"):
            default_resources = trainable_cls.default_resource_request(
                self.config)
            if default_resources:
                if resources:
                    raise ValueError(
                        "Resources for {} have been automatically set to {} "
                        "by its `default_resource_request()` method. Please "
                        "clear the `resources_per_trial` option.".format(
                            trainable_cls, default_resources))
                resources = default_resources
        self.location = Location()
        self.resources = resources or Resources(cpu=1, gpu=0)
        self.stopping_criterion = stopping_criterion or {}
        self.loggers = loggers
        self.sync_to_driver_fn = sync_to_driver_fn
        self.verbose = True
        self.max_failures = max_failures

        # Local trial state that is updated during the run
        self.last_result = {}
        self.last_update_time = -float("inf")

        # stores in memory max/min/last result for each metric by trial
        self.metric_analysis = {}

        self.export_formats = export_formats
        self.status = Trial.PENDING
        self.start_time = None
        self.logdir = None
        self.runner = None
        self.result_logger = None
        self.last_debug = 0
        self.error_file = None
        self.error_msg = None
        self.custom_trial_name = None

        # Checkpointing fields
        if remote_checkpoint_dir:
            self.remote_checkpoint_dir_prefix = remote_checkpoint_dir
        else:
            self.remote_checkpoint_dir_prefix = None
        self.checkpoint_freq = checkpoint_freq
        self.checkpoint_at_end = checkpoint_at_end
        self.sync_on_checkpoint = sync_on_checkpoint
        newest_checkpoint = Checkpoint(Checkpoint.PERSISTENT, restore_path)
        self.checkpoint_manager = CheckpointManager(
            keep_checkpoints_num, checkpoint_score_attr,
            checkpoint_deleter(str(self), self.runner))
        self.checkpoint_manager.newest_checkpoint = newest_checkpoint

        # Restoration fields
        self.restoring_from = None
        self.num_failures = 0
        self.num_consecutive_start_attempts = 0

        # AutoML fields
        self.results = None
        self.best_result = None
        self.param_config = None
        self.extra_arg = None

        self._nonjson_fields = [
            "loggers",
            "sync_to_driver_fn",
            "results",
            "best_result",
            "param_config",
            "extra_arg",
        ]
        if trial_name_creator:
            self.custom_trial_name = trial_name_creator(self)

    @property
    def node_ip(self):
        return self.location.hostname

    @property
    def checkpoint(self):
        return self.checkpoint_manager.newest_checkpoint

    @classmethod
    def generate_id(cls):
        return str(uuid.uuid1().hex)[:8]

    @property
    def remote_checkpoint_dir(self):
        assert self.logdir, "Trial {}: logdir not initialized.".format(self)
        if not self.remote_checkpoint_dir_prefix:
            return None
        logdir_name = os.path.basename(self.logdir)
        return os.path.join(self.remote_checkpoint_dir_prefix, logdir_name)

    @classmethod
    def create_logdir(cls, identifier, local_dir):
        local_dir = os.path.expanduser(local_dir)
        os.makedirs(local_dir, exist_ok=True)
        return tempfile.mkdtemp(prefix="{}_{}".format(
            identifier[:MAX_LEN_IDENTIFIER], date_str()),
                                dir=local_dir)

    def init_logger(self):
        """Init logger."""
        if not self.result_logger:
            if not self.logdir:
                self.logdir = Trial.create_logdir(str(self), self.local_dir)
            else:
                os.makedirs(self.logdir, exist_ok=True)

            self.result_logger = UnifiedLogger(
                self.config,
                self.logdir,
                trial=self,
                loggers=self.loggers,
                sync_function=self.sync_to_driver_fn)

    def update_resources(self, cpu, gpu, **kwargs):
        """EXPERIMENTAL: Updates the resource requirements.

        Should only be called when the trial is not running.

        Raises:
            ValueError if trial status is running.
        """
        if self.status is Trial.RUNNING:
            raise ValueError("Cannot update resources while Trial is running.")
        self.resources = Resources(cpu, gpu, **kwargs)

    def set_runner(self, runner):
        self.runner = runner
        self.checkpoint_manager.delete = checkpoint_deleter(str(self), runner)

    def set_location(self, location):
        """Sets the location of the trial."""
        self.location = location

    def set_status(self, status):
        """Sets the status of the trial."""
        self.status = status
        if status == Trial.RUNNING:
            if self.start_time is None:
                self.start_time = time.time()

    def close_logger(self):
        """Closes logger."""
        if self.result_logger:
            self.result_logger.close()
            self.result_logger = None

    def write_error_log(self, error_msg):
        if error_msg and self.logdir:
            self.num_failures += 1
            self.error_file = os.path.join(self.logdir, "error.txt")
            with open(self.error_file, "a+") as f:
                f.write("Failure # {} (occurred at {})\n".format(
                    self.num_failures, date_str()))
                f.write(error_msg + "\n")
            self.error_msg = error_msg

    def should_stop(self, result):
        """Whether the given result meets this trial's stopping criteria."""
        if result.get(DONE):
            return True

        if callable(self.stopping_criterion):
            return self.stopping_criterion(self.trial_id, result)

        for criteria, stop_value in self.stopping_criterion.items():
            if criteria not in result:
                raise TuneError(
                    "Stopping criteria {} not provided in result {}.".format(
                        criteria, result))
            elif isinstance(criteria, dict):
                raise ValueError(
                    "Stopping criteria is now flattened by default. "
                    "Use forward slashes to nest values `key1/key2/key3`.")
            elif result[criteria] >= stop_value:
                return True
        return False

    def should_checkpoint(self):
        """Whether this trial is due for checkpointing."""
        result = self.last_result or {}
        if result.get(DONE) and self.checkpoint_at_end:
            return True
        return (self.checkpoint_freq and
                result.get(TRAINING_ITERATION, 0) % self.checkpoint_freq == 0)

    def has_checkpoint(self):
        return self.checkpoint.value is not None

    def clear_checkpoint(self):
        self.checkpoint.value = None
        self.restoring_from = None

    def on_checkpoint(self, checkpoint):
        """Hook for handling checkpoints taken by the Trainable.

        Args:
            checkpoint (Checkpoint): Checkpoint taken.
        """
        if checkpoint.storage == Checkpoint.MEMORY:
            # TODO(ujvl): Handle this separately to avoid restoration failure.
            self.checkpoint_manager.on_checkpoint(checkpoint)
            return
        if self.sync_on_checkpoint:
            try:
                # Wait for any other syncs to finish. We need to sync again
                # after this to handle checkpoints taken mid-sync.
                self.result_logger.wait()
            except TuneError as e:
                # Errors occurring during this wait are not fatal for this
                # checkpoint, so it should just be logged.
                logger.error(
                    "Trial %s: An error occurred during the "
                    "checkpoint pre-sync wait.", str(e))
            # Force sync down and wait before tracking the new checkpoint.
            try:
                if self.result_logger.sync_down():
                    self.result_logger.wait()
                else:
                    logger.error(
                        "Trial %s: Checkpoint sync skipped. "
                        "This should not happen.", self)
            except TuneError as e:
                if issubclass(self.get_trainable_cls(), DurableTrainable):
                    # Even though rsync failed the trainable can restore
                    # from remote durable storage.
                    logger.error("Trial %s: Sync error - %s", self, str(e))
                else:
                    # If the trainable didn't have remote storage to upload
                    # to then this checkpoint may have been lost, so we
                    # shouldn't track it with the checkpoint_manager.
                    raise e
            if not issubclass(self.get_trainable_cls(), DurableTrainable):
                if not os.path.exists(checkpoint.value):
                    raise TuneError("Trial {}: Checkpoint path {} not "
                                    "found after successful sync down.".format(
                                        self, checkpoint.value))
        self.checkpoint_manager.on_checkpoint(checkpoint)

    def on_restore(self):
        """Handles restoration completion."""
        assert self.is_restoring
        self.last_result = self.restoring_from.result
        self.restoring_from = None

    def should_recover(self):
        """Returns whether the trial qualifies for retrying.

        This is if the trial has not failed more than max_failures. Note this
        may return true even when there is no checkpoint, either because
        `self.checkpoint_freq` is `0` or because the trial failed before
        a checkpoint has been made.
        """
        return self.num_failures < self.max_failures or self.max_failures < 0

    def update_last_result(self, result, terminate=False):
        result.update(trial_id=self.trial_id, done=terminate)
        if self.experiment_tag:
            result.update(experiment_tag=self.experiment_tag)
        if self.verbose and (terminate or time.time() - self.last_debug >
                             DEBUG_PRINT_INTERVAL):
            print("Result for {}:".format(self))
            print("  {}".format(pretty_print(result).replace("\n", "\n  ")))
            self.last_debug = time.time()
        self.set_location(Location(result.get("node_ip"), result.get("pid")))
        self.last_result = result
        self.last_update_time = time.time()
        self.result_logger.on_result(self.last_result)
        for metric, value in flatten_dict(result).items():
            if isinstance(value, Number):
                if metric not in self.metric_analysis:
                    self.metric_analysis[metric] = {
                        "max": value,
                        "min": value,
                        "last": value
                    }
                else:
                    self.metric_analysis[metric]["max"] = max(
                        value, self.metric_analysis[metric]["max"])
                    self.metric_analysis[metric]["min"] = min(
                        value, self.metric_analysis[metric]["min"])
                    self.metric_analysis[metric]["last"] = value

    def get_trainable_cls(self):
        return get_trainable_cls(self.trainable_name)

    def set_verbose(self, verbose):
        self.verbose = verbose

    def is_finished(self):
        return self.status in [Trial.ERROR, Trial.TERMINATED]

    @property
    def is_restoring(self):
        return self.restoring_from is not None

    def __repr__(self):
        return str(self)

    def __str__(self):
        """Combines ``env`` with ``trainable_name`` and ``trial_id``.

        Can be overridden with a custom string creator.
        """
        if self.custom_trial_name:
            return self.custom_trial_name

        if "env" in self.config:
            env = self.config["env"]
            if isinstance(env, type):
                env = env.__name__
            identifier = "{}_{}".format(self.trainable_name, env)
        else:
            identifier = self.trainable_name
        identifier += "_" + self.trial_id
        return identifier.replace("/", "_")

    def __getstate__(self):
        """Memento generator for Trial.

        Sets RUNNING trials to PENDING, and flushes the result logger.
        Note this can only occur if the trial holds a PERSISTENT checkpoint.
        """
        assert self.checkpoint.storage == Checkpoint.PERSISTENT, (
            "Checkpoint must not be in-memory.")
        state = self.__dict__.copy()
        state["resources"] = resources_to_json(self.resources)

        for key in self._nonjson_fields:
            state[key] = binary_to_hex(cloudpickle.dumps(state.get(key)))

        state["runner"] = None
        state["result_logger"] = None
        if self.result_logger:
            self.result_logger.flush(sync_down=False)
            state["__logger_started__"] = True
        else:
            state["__logger_started__"] = False
        return copy.deepcopy(state)

    def __setstate__(self, state):
        logger_started = state.pop("__logger_started__")
        state["resources"] = json_to_resources(state["resources"])

        if state["status"] == Trial.RUNNING:
            state["status"] = Trial.PENDING
        for key in self._nonjson_fields:
            state[key] = cloudpickle.loads(hex_to_binary(state[key]))

        self.__dict__.update(state)
        validate_trainable(self.trainable_name)
        if logger_started:
            self.init_logger()
Пример #6
0
class Trainable:
    """Abstract class for trainable models, functions, etc.

    A call to ``train()`` on a trainable will execute one logical iteration of
    training. As a rule of thumb, the execution time of one train call should
    be large enough to avoid overheads (i.e. more than a few seconds), but
    short enough to report progress periodically (i.e. at most a few minutes).

    Calling ``save()`` should save the training state of a trainable to disk,
    and ``restore(path)`` should restore a trainable to the given state.

    Generally you only need to implement ``setup``, ``step``,
    ``save_checkpoint``, and ``load_checkpoint`` when subclassing Trainable.

    Other implementation methods that may be helpful to override are
    ``log_result``, ``reset_config``, ``cleanup``, and ``_export_model``.

    When using Tune, Tune will convert this class into a Ray actor, which
    runs on a separate process. Tune will also change the current working
    directory of this process to ``self.logdir``. This is designed so that
    different trials that run on the same physical node won't accidently
    write to the same location and overstep each other.

    If you want to know the orginal working directory path on the driver node,
    you can do so through env variable "TUNE_ORIG_WORKING_DIR".
    It is advised that you access this path for read only purposes and you
    need to make sure that the path exists on the remote nodes.

    This class supports checkpointing to and restoring from remote storage.


    """

    _sync_function_tpl = None

    def __init__(
        self,
        config: Dict[str, Any] = None,
        logger_creator: Callable[[Dict[str, Any]], Logger] = None,
        remote_checkpoint_dir: Optional[str] = None,
        sync_function_tpl: Optional[str] = None,
    ):
        """Initialize an Trainable.

        Sets up logging and points ``self.logdir`` to a directory in which
        training outputs should be placed.

        Subclasses should prefer defining ``setup()`` instead of overriding
        ``__init__()`` directly.

        Args:
            config (dict): Trainable-specific configuration data. By default
                will be saved as ``self.config``.
            logger_creator (func): Function that creates a ray.tune.Logger
                object. If unspecified, a default logger is created.
            remote_checkpoint_dir (str): Upload directory (S3 or GS path).
                This is **per trial** directory,
                which is different from **per checkpoint** directory.
            sync_function_tpl (str): Sync function template to use. Defaults
              to `cls._sync_function` (which defaults to `None`).
        """

        self._experiment_id = uuid.uuid4().hex
        self.config = config or {}
        trial_info = self.config.pop(TRIAL_INFO, None)

        if self.is_actor():
            disable_ipython()

        self._result_logger = self._logdir = None
        self._create_logger(self.config, logger_creator)

        self._stdout_context = self._stdout_fp = self._stdout_stream = None
        self._stderr_context = self._stderr_fp = self._stderr_stream = None
        self._stderr_logging_handler = None

        stdout_file = self.config.pop(STDOUT_FILE, None)
        stderr_file = self.config.pop(STDERR_FILE, None)
        self._open_logfiles(stdout_file, stderr_file)

        self._iteration = 0
        self._time_total = 0.0
        self._timesteps_total = None
        self._episodes_total = None
        self._time_since_restore = 0.0
        self._timesteps_since_restore = 0
        self._iterations_since_restore = 0
        self._restored = False
        self._trial_info = trial_info
        self._stdout_file = stdout_file
        self._stderr_file = stderr_file

        start_time = time.time()
        self._local_ip = self.get_current_ip()
        self.setup(copy.deepcopy(self.config))
        setup_time = time.time() - start_time
        if setup_time > SETUP_TIME_THRESHOLD:
            logger.info("Trainable.setup took {:.3f} seconds. If your "
                        "trainable is slow to initialize, consider setting "
                        "reuse_actors=True to reduce actor creation "
                        "overheads.".format(setup_time))
        log_sys_usage = self.config.get("log_sys_usage", False)
        self._start_time = start_time
        self._warmup_time = None
        self._monitor = UtilMonitor(start=log_sys_usage)

        self.remote_checkpoint_dir = remote_checkpoint_dir
        self.sync_function_tpl = sync_function_tpl or self._sync_function_tpl
        self.storage_client = None

        if self.uses_cloud_checkpointing:
            self.storage_client = self._create_storage_client()

    @property
    def uses_cloud_checkpointing(self):
        return bool(self.remote_checkpoint_dir)

    def _create_storage_client(self):
        """Returns a storage client."""
        return get_sync_client(
            self.sync_function_tpl) or get_cloud_sync_client(
                self.remote_checkpoint_dir)

    def _storage_path(self, local_path):
        """Converts a `local_path` to be based off of
        `self.remote_checkpoint_dir`."""
        rel_local_path = os.path.relpath(local_path, self.logdir)
        return os.path.join(self.remote_checkpoint_dir, rel_local_path)

    @classmethod
    def default_resource_request(
            cls, config: Dict[str,
                              Any]) -> Union[Resources, PlacementGroupFactory]:
        """Provides a static resource requirement for the given configuration.

        This can be overridden by sub-classes to set the correct trial resource
        allocation, so the user does not need to.

        .. code-block:: python

            @classmethod
            def default_resource_request(cls, config):
                return PlacementGroupFactory([{"CPU": 1}, {"CPU": 1}]])


        Args:
            config[Dict[str, Any]]: The Trainable's config dict.

        Returns:
            Union[Resources, PlacementGroupFactory]: A Resources object or
                PlacementGroupFactory consumed by Tune for queueing.
        """
        return None

    @classmethod
    def resource_help(cls, config):
        """Returns a help string for configuring this trainable's resources.

        Args:
            config (dict): The Trainer's config dict.
        """
        return ""

    def get_current_ip(self):
        self._local_ip = ray.util.get_node_ip_address()
        return self._local_ip

    def get_auto_filled_metrics(
        self,
        now: Optional[datetime] = None,
        time_this_iter: Optional[float] = None,
        debug_metrics_only: bool = False,
    ) -> dict:
        """Return a dict with metrics auto-filled by the trainable.

        If ``debug_metrics_only`` is True, only metrics that don't
        require at least one iteration will be returned
        (``ray.tune.result.DEBUG_METRICS``).
        """
        if now is None:
            now = datetime.today()
        autofilled = {
            TRIAL_ID: self.trial_id,
            "experiment_id": self._experiment_id,
            "date": now.strftime("%Y-%m-%d_%H-%M-%S"),
            "timestamp": int(time.mktime(now.timetuple())),
            TIME_THIS_ITER_S: time_this_iter,
            TIME_TOTAL_S: self._time_total,
            PID: os.getpid(),
            HOSTNAME: platform.node(),
            NODE_IP: self._local_ip,
            "config": self.config,
            "time_since_restore": self._time_since_restore,
            "timesteps_since_restore": self._timesteps_since_restore,
            "iterations_since_restore": self._iterations_since_restore,
            "warmup_time": self._warmup_time,
        }
        if debug_metrics_only:
            autofilled = {
                k: v
                for k, v in autofilled.items() if k in DEBUG_METRICS
            }
        return autofilled

    def is_actor(self):
        try:
            actor_id = ray.worker.global_worker.actor_id
            return actor_id != actor_id.nil()
        except Exception:
            # If global_worker is not instantiated, we're not in an actor
            return False

    def train_buffered(self,
                       buffer_time_s: float,
                       max_buffer_length: int = 1000):
        """Runs multiple iterations of training.

        Calls ``train()`` internally. Collects and combines multiple results.
        This function will run ``self.train()`` repeatedly until one of
        the following conditions is met: 1) the maximum buffer length is
        reached, 2) the maximum buffer time is reached, or 3) a checkpoint
        was created. Even if the maximum time is reached, it will always
        block until at least one result is received.

        Args:
            buffer_time_s (float): Maximum time to buffer. The next result
                received after this amount of time has passed will return
                the whole buffer.
            max_buffer_length (int): Maximum number of results to buffer.

        """
        results = []

        now = time.time()
        send_buffer_at = now + buffer_time_s
        while now < send_buffer_at or not results:  # At least one result
            result = self.train()
            results.append(result)
            if result.get(DONE, False):
                # If the trial is done, return
                break
            elif result.get(SHOULD_CHECKPOINT, False):
                # If a checkpoint was created, return
                break
            elif result.get(RESULT_DUPLICATE):
                # If the function API trainable completed, return
                break
            elif len(results) >= max_buffer_length:
                # If the buffer is full, return
                break
            now = time.time()

        return results

    def train(self):
        """Runs one logical iteration of training.

        Calls ``step()`` internally. Subclasses should override ``step()``
        instead to return results.
        This method automatically fills the following fields in the result:

            `done` (bool): training is terminated. Filled only if not provided.

            `time_this_iter_s` (float): Time in seconds this iteration
            took to run. This may be overridden in order to override the
            system-computed time difference.

            `time_total_s` (float): Accumulated time in seconds for this
            entire experiment.

            `experiment_id` (str): Unique string identifier
            for this experiment. This id is preserved
            across checkpoint / restore calls.

            `training_iteration` (int): The index of this
            training iteration, e.g. call to train(). This is incremented
            after `step()` is called.

            `pid` (str): The pid of the training process.

            `date` (str): A formatted date of when the result was processed.

            `timestamp` (str): A UNIX timestamp of when the result
            was processed.

            `hostname` (str): Hostname of the machine hosting the training
            process.

            `node_ip` (str): Node ip of the machine hosting the training
            process.

        Returns:
            A dict that describes training progress.
        """
        if self._warmup_time is None:
            self._warmup_time = time.time() - self._start_time
        start = time.time()
        result = self.step()
        assert isinstance(result, dict), "step() needs to return a dict."

        # We do not modify internal state nor update this result if duplicate.
        if RESULT_DUPLICATE in result:
            return result

        result = result.copy()

        self._iteration += 1
        self._iterations_since_restore += 1

        if result.get(TIME_THIS_ITER_S) is not None:
            time_this_iter = result[TIME_THIS_ITER_S]
        else:
            time_this_iter = time.time() - start
        self._time_total += time_this_iter
        self._time_since_restore += time_this_iter

        result.setdefault(DONE, False)

        # self._timesteps_total should only be tracked if increments provided
        if result.get(TIMESTEPS_THIS_ITER) is not None:
            if self._timesteps_total is None:
                self._timesteps_total = 0
            self._timesteps_total += result[TIMESTEPS_THIS_ITER]
            self._timesteps_since_restore += result[TIMESTEPS_THIS_ITER]

        # self._episodes_total should only be tracked if increments provided
        if result.get(EPISODES_THIS_ITER) is not None:
            if self._episodes_total is None:
                self._episodes_total = 0
            self._episodes_total += result[EPISODES_THIS_ITER]

        # self._timesteps_total should not override user-provided total
        result.setdefault(TIMESTEPS_TOTAL, self._timesteps_total)
        result.setdefault(EPISODES_TOTAL, self._episodes_total)
        result.setdefault(TRAINING_ITERATION, self._iteration)

        # Provides auto-filled neg_mean_loss for avoiding regressions
        if result.get("mean_loss"):
            result.setdefault("neg_mean_loss", -result["mean_loss"])

        now = datetime.today()
        result.update(self.get_auto_filled_metrics(now, time_this_iter))

        monitor_data = self._monitor.get_data()
        if monitor_data:
            result.update(monitor_data)

        self.log_result(result)

        if self._stdout_context:
            self._stdout_stream.flush()
        if self._stderr_context:
            self._stderr_stream.flush()

        return result

    def get_state(self):
        return {
            "experiment_id": self._experiment_id,
            "iteration": self._iteration,
            "timesteps_total": self._timesteps_total,
            "time_total": self._time_total,
            "episodes_total": self._episodes_total,
            "ray_version": ray.__version__,
        }

    def save(self, checkpoint_dir=None) -> str:
        """Saves the current model state to a checkpoint.

        Subclasses should override ``save_checkpoint()`` instead to save state.
        This method dumps additional metadata alongside the saved path.

        If a remote checkpoint dir is given, this will also sync up to remote
        storage.

        Args:
            checkpoint_dir (str): Optional dir to place the checkpoint.

        Returns:
            str: path that points to xxx.pkl file.

        Note the return path should match up with what is expected of
        `restore()`.
        """
        checkpoint_dir = TrainableUtil.make_checkpoint_dir(
            checkpoint_dir or self.logdir, index=self.iteration)
        checkpoint = self.save_checkpoint(checkpoint_dir)
        trainable_state = self.get_state()
        checkpoint_path = TrainableUtil.process_checkpoint(
            checkpoint,
            parent_dir=checkpoint_dir,
            trainable_state=trainable_state)

        self._postprocess_checkpoint(checkpoint_dir)

        # Maybe sync to cloud
        self._maybe_save_to_cloud(checkpoint_dir)

        return checkpoint_path

    def _postprocess_checkpoint(self, checkpoint_path: str):
        """Run extra postprocessing before the checkpoint is saved to cloud."""
        pass

    def _maybe_save_to_cloud(self, checkpoint_dir):
        # Derived classes like the FunctionRunner might call this
        if self.uses_cloud_checkpointing:
            self.storage_client.sync_up(checkpoint_dir,
                                        self._storage_path(checkpoint_dir))
            self.storage_client.wait_or_retry()

    def save_to_object(self):
        """Saves the current model state to a Python object.

        It also saves to disk but does not return the checkpoint path.

        Returns:
            Object holding checkpoint data.
        """
        tmpdir = tempfile.mkdtemp("save_to_object", dir=self.logdir)
        checkpoint_path = self.save(tmpdir)
        # Save all files in subtree and delete the tmpdir.
        obj = TrainableUtil.checkpoint_to_object(checkpoint_path)
        shutil.rmtree(tmpdir)
        return obj

    def restore(self, checkpoint_path):
        """Restores training state from a given model checkpoint.

        These checkpoints are returned from calls to save().

        Subclasses should override ``load_checkpoint()`` instead to
        restore state.
        This method restores additional metadata saved with the checkpoint.

        `checkpoint_path` should match with the return from ``save()``.

        `checkpoint_path` can be
        `~/ray_results/exp/MyTrainable_abc/
        checkpoint_00000/checkpoint`. Or,
        `~/ray_results/exp/MyTrainable_abc/checkpoint_00000`.

        `self.logdir` should generally be corresponding to `checkpoint_path`,
        for example, `~/ray_results/exp/MyTrainable_abc`.

        `self.remote_checkpoint_dir` in this case, is something like,
        `REMOTE_CHECKPOINT_BUCKET/exp/MyTrainable_abc`
        """
        if self.uses_cloud_checkpointing:
            rel_checkpoint_dir = TrainableUtil.find_rel_checkpoint_dir(
                self.logdir, checkpoint_path)
            self.storage_client.sync_down(
                os.path.join(self.remote_checkpoint_dir, rel_checkpoint_dir),
                os.path.join(self.logdir, rel_checkpoint_dir),
            )
            self.storage_client.wait_or_retry()

        # Ensure TrialCheckpoints are converted
        if isinstance(checkpoint_path, TrialCheckpoint):
            checkpoint_path = checkpoint_path.local_path

        with open(checkpoint_path + ".tune_metadata", "rb") as f:
            metadata = pickle.load(f)
        self._experiment_id = metadata["experiment_id"]
        self._iteration = metadata["iteration"]
        self._timesteps_total = metadata["timesteps_total"]
        self._time_total = metadata["time_total"]
        self._episodes_total = metadata["episodes_total"]
        saved_as_dict = metadata["saved_as_dict"]
        if saved_as_dict:
            with open(checkpoint_path, "rb") as loaded_state:
                checkpoint_dict = pickle.load(loaded_state)
            checkpoint_dict.update(tune_checkpoint_path=checkpoint_path)
            self.load_checkpoint(checkpoint_dict)
        else:
            self.load_checkpoint(checkpoint_path)
        self._time_since_restore = 0.0
        self._timesteps_since_restore = 0
        self._iterations_since_restore = 0
        self._restored = True
        logger.info("Restored on %s from checkpoint: %s",
                    self.get_current_ip(), checkpoint_path)
        state = {
            "_iteration": self._iteration,
            "_timesteps_total": self._timesteps_total,
            "_time_total": self._time_total,
            "_episodes_total": self._episodes_total,
        }
        logger.info("Current state after restoring: %s", state)

    def restore_from_object(self, obj):
        """Restores training state from a checkpoint object.

        These checkpoints are returned from calls to save_to_object().
        """
        tmpdir = tempfile.mkdtemp("restore_from_object", dir=self.logdir)
        checkpoint_path = TrainableUtil.create_from_pickle(obj, tmpdir)
        self.restore(checkpoint_path)
        shutil.rmtree(tmpdir)

    def delete_checkpoint(self, checkpoint_path):
        """Deletes local copy of checkpoint.

        Args:
            checkpoint_path (str): Path to checkpoint.
        """
        # Ensure TrialCheckpoints are converted
        if isinstance(checkpoint_path, TrialCheckpoint):
            checkpoint_path = checkpoint_path.local_path

        try:
            checkpoint_dir = TrainableUtil.find_checkpoint_dir(checkpoint_path)
        except FileNotFoundError:
            # The checkpoint won't exist locally if the
            # trial was rescheduled to another worker.
            logger.debug(
                f"Local checkpoint not found during garbage collection: "
                f"{self.trial_id} - {checkpoint_path}")
            return
        else:
            if self.uses_cloud_checkpointing:
                self.storage_client.delete(self._storage_path(checkpoint_dir))
                self.storage_client.wait_or_retry()

        if os.path.exists(checkpoint_dir):
            shutil.rmtree(checkpoint_dir)

    def export_model(self, export_formats, export_dir=None):
        """Exports model based on export_formats.

        Subclasses should override _export_model() to actually
        export model to local directory.

        Args:
            export_formats (Union[list,str]): Format or list of (str) formats
                that should be exported.
            export_dir (str): Optional dir to place the exported model.
                Defaults to self.logdir.

        Returns:
            A dict that maps ExportFormats to successfully exported models.
        """
        if isinstance(export_formats, str):
            export_formats = [export_formats]
        export_dir = export_dir or self.logdir
        return self._export_model(export_formats, export_dir)

    def reset(self, new_config, logger_creator=None):
        """Resets trial for use with new config.

        Subclasses should override reset_config() to actually
        reset actor behavior for the new config."""
        self.config = new_config

        trial_info = new_config.pop(TRIAL_INFO, None)
        if trial_info:
            self._trial_info = trial_info

        self._result_logger.flush()
        self._result_logger.close()

        if logger_creator:
            logger.debug("Logger reset.")
            self._create_logger(new_config.copy(), logger_creator)
        else:
            logger.debug("Did not reset logger. Got: "
                         f"trainable.reset(logger_creator={logger_creator}).")

        stdout_file = new_config.pop(STDOUT_FILE, None)
        stderr_file = new_config.pop(STDERR_FILE, None)

        self._close_logfiles()
        self._open_logfiles(stdout_file, stderr_file)

        success = self.reset_config(new_config)
        if not success:
            return False

        # Reset attributes. Will be overwritten by `restore` if a checkpoint
        # is provided.
        self._iteration = 0
        self._time_total = 0.0
        self._timesteps_total = None
        self._episodes_total = None
        self._time_since_restore = 0.0
        self._timesteps_since_restore = 0
        self._iterations_since_restore = 0
        self._restored = False

        return True

    def reset_config(self, new_config):
        """Resets configuration without restarting the trial.

        This method is optional, but can be implemented to speed up algorithms
        such as PBT, and to allow performance optimizations such as running
        experiments with reuse_actors=True.

        Args:
            new_config (dict): Updated hyperparameter configuration
                for the trainable.

        Returns:
            True if reset was successful else False.
        """
        return False

    def _create_logger(
        self,
        config: Dict[str, Any],
        logger_creator: Callable[[Dict[str, Any]], Logger] = None,
    ):
        """Create logger from logger creator.

        Sets _logdir and _result_logger.

        `_logdir` is the **per trial** directory for the Trainable.
        """
        if logger_creator:
            self._result_logger = logger_creator(config)
            self._logdir = self._result_logger.logdir
        else:
            from ray.tune.logger import UnifiedLogger

            logdir_prefix = datetime.today().strftime("%Y-%m-%d_%H-%M-%S")
            ray._private.utils.try_to_create_directory(DEFAULT_RESULTS_DIR)
            self._logdir = tempfile.mkdtemp(prefix=logdir_prefix,
                                            dir=DEFAULT_RESULTS_DIR)
            self._result_logger = UnifiedLogger(config,
                                                self._logdir,
                                                loggers=None)

    def _open_logfiles(self, stdout_file, stderr_file):
        """Create loggers. Open stdout and stderr logfiles."""
        if stdout_file:
            stdout_path = os.path.expanduser(
                os.path.join(self._logdir, stdout_file))
            self._stdout_fp = open(stdout_path, "a+")
            self._stdout_stream = Tee(sys.stdout, self._stdout_fp)
            self._stdout_context = redirect_stdout(self._stdout_stream)
            self._stdout_context.__enter__()

        if stderr_file:
            stderr_path = os.path.expanduser(
                os.path.join(self._logdir, stderr_file))
            self._stderr_fp = open(stderr_path, "a+")
            self._stderr_stream = Tee(sys.stderr, self._stderr_fp)
            self._stderr_context = redirect_stderr(self._stderr_stream)
            self._stderr_context.__enter__()

            # Add logging handler to root ray logger
            formatter = logging.Formatter("[%(levelname)s %(asctime)s] "
                                          "%(filename)s: %(lineno)d  "
                                          "%(message)s")
            self._stderr_logging_handler = logging.StreamHandler(
                self._stderr_fp)
            self._stderr_logging_handler.setFormatter(formatter)
            ray.logger.addHandler(self._stderr_logging_handler)

    def _close_logfiles(self):
        """Close stdout and stderr logfiles."""
        if self._stderr_logging_handler:
            ray.logger.removeHandler(self._stderr_logging_handler)

        if self._stdout_context:
            self._stdout_stream.flush()
            self._stdout_context.__exit__(None, None, None)
            self._stdout_fp.close()
            self._stdout_context = None
        if self._stderr_context:
            self._stderr_stream.flush()
            self._stderr_context.__exit__(None, None, None)
            self._stderr_fp.close()
            self._stderr_context = None

    def stop(self):
        """Releases all resources used by this trainable.

        Calls ``Trainable.cleanup`` internally. Subclasses should override
        ``Trainable.cleanup`` for custom cleanup procedures.
        """
        self._result_logger.flush()
        self._result_logger.close()
        if self._monitor.is_alive():
            self._monitor.stop()
            self._monitor.join()
        self.cleanup()

        self._close_logfiles()

    @property
    def logdir(self):
        """Directory of the results and checkpoints for this Trainable.

        Tune will automatically sync this folder with the driver if execution
        is distributed.

        Note that the current working directory will also be changed to this.

        """
        return os.path.join(self._logdir, "")

    @property
    def trial_name(self):
        """Trial name for the corresponding trial of this Trainable.

        This is not set if not using Tune.

        .. code-block:: python

            name = self.trial_name
        """
        if self._trial_info:
            return self._trial_info.trial_name
        else:
            return "default"

    @property
    def trial_id(self):
        """Trial ID for the corresponding trial of this Trainable.

        This is not set if not using Tune.

        .. code-block:: python

            trial_id = self.trial_id
        """
        if self._trial_info:
            return self._trial_info.trial_id
        else:
            return "default"

    @property
    def trial_resources(self) -> Union[Resources, PlacementGroupFactory]:
        """Resources currently assigned to the trial of this Trainable.

        This is not set if not using Tune.

        .. code-block:: python

            trial_resources = self.trial_resources
        """
        if self._trial_info:
            return self._trial_info.trial_resources
        else:
            return "default"

    @property
    def iteration(self):
        """Current training iteration.

        This value is automatically incremented every time `train()` is called
        and is automatically inserted into the training result dict.

        """
        return self._iteration

    @property
    def training_iteration(self):
        """Current training iteration (same as `self.iteration`).

        This value is automatically incremented every time `train()` is called
        and is automatically inserted into the training result dict.

        """
        return self._iteration

    def get_config(self):
        """Returns configuration passed in by Tune."""
        return self.config

    def step(self):
        """Subclasses should override this to implement train().

        The return value will be automatically passed to the loggers. Users
        can also return `tune.result.DONE` or `tune.result.SHOULD_CHECKPOINT`
        as a key to manually trigger termination or checkpointing of this
        trial. Note that manual checkpointing only works when subclassing
        Trainables.

        .. versionadded:: 0.8.7

        Returns:
            A dict that describes training progress.

        """
        if self._implements_method("_train") and log_once("_train"):
            raise DeprecationWarning(
                "Trainable._train is deprecated and is now removed. Override "
                "Trainable.step instead.")
        raise NotImplementedError

    def save_checkpoint(self, tmp_checkpoint_dir):
        """Subclasses should override this to implement ``save()``.

        Warning:
            Do not rely on absolute paths in the implementation of
            ``Trainable.save_checkpoint`` and ``Trainable.load_checkpoint``.

        Use ``validate_save_restore`` to catch ``Trainable.save_checkpoint``/
        ``Trainable.load_checkpoint`` errors before execution.

        >>> from ray.tune.utils import validate_save_restore
        >>> validate_save_restore(MyTrainableClass)
        >>> validate_save_restore(MyTrainableClass, use_object_store=True)

        .. versionadded:: 0.8.7

        Args:
            tmp_checkpoint_dir (str): The directory where the checkpoint
                file must be stored. In a Tune run, if the trial is paused,
                the provided path may be temporary and moved.

        Returns:
            A dict or string. If string, the return value is expected to be
            prefixed by `tmp_checkpoint_dir`. If dict, the return value will
            be automatically serialized by Tune and
            passed to ``Trainable.load_checkpoint()``.

        Examples:
            >>> print(trainable1.save_checkpoint("/tmp/checkpoint_1"))
            "/tmp/checkpoint_1/my_checkpoint_file"
            >>> print(trainable2.save_checkpoint("/tmp/checkpoint_2"))
            {"some": "data"}

            >>> trainable.save_checkpoint("/tmp/bad_example")
            "/tmp/NEW_CHECKPOINT_PATH/my_checkpoint_file" # This will error.
        """
        if self._implements_method("_save") and log_once("_save"):
            raise DeprecationWarning(
                "Trainable._save is deprecated and is now removed. Override "
                "Trainable.save_checkpoint instead.")
        raise NotImplementedError

    def load_checkpoint(self, checkpoint):
        """Subclasses should override this to implement restore().

        Warning:
            In this method, do not rely on absolute paths. The absolute
            path of the checkpoint_dir used in ``Trainable.save_checkpoint``
            may be changed.

        If ``Trainable.save_checkpoint`` returned a prefixed string, the
        prefix of the checkpoint string returned by
        ``Trainable.save_checkpoint`` may be changed.
        This is because trial pausing depends on temporary directories.

        The directory structure under the checkpoint_dir provided to
        ``Trainable.save_checkpoint`` is preserved.

        See the example below.

        .. code-block:: python

            class Example(Trainable):
                def save_checkpoint(self, checkpoint_path):
                    print(checkpoint_path)
                    return os.path.join(checkpoint_path, "my/check/point")

                def load_checkpoint(self, checkpoint):
                    print(checkpoint)

            >>> trainer = Example()
            >>> obj = trainer.save_to_object()  # This is used when PAUSED.
            <logdir>/tmpc8k_c_6hsave_to_object/checkpoint_0/my/check/point
            >>> trainer.restore_from_object(obj)  # Note the different prefix.
            <logdir>/tmpb87b5axfrestore_from_object/checkpoint_0/my/check/point

        .. versionadded:: 0.8.7

        Args:
            checkpoint (str|dict): If dict, the return value is as
                returned by `save_checkpoint`. If a string, then it is
                a checkpoint path that may have a different prefix than that
                returned by `save_checkpoint`. The directory structure
                underneath the `checkpoint_dir` `save_checkpoint` is preserved.
        """
        if self._implements_method("_restore") and log_once("_restore"):
            raise DeprecationWarning(
                "Trainable._restore is deprecated and is now removed. "
                "Override Trainable.load_checkpoint instead.")
        raise NotImplementedError

    def setup(self, config):
        """Subclasses should override this for custom initialization.

        .. versionadded:: 0.8.7

        Args:
            config (dict): Hyperparameters and other configs given.
                Copy of `self.config`.

        """
        if self._implements_method("_setup") and log_once("_setup"):
            raise DeprecationWarning(
                "Trainable._setup is deprecated and is now removed. Override "
                "Trainable.setup instead.")
        pass

    def log_result(self, result):
        """Subclasses can optionally override this to customize logging.

        The logging here is done on the worker process rather than
        the driver. You may want to turn off driver logging via the
        ``loggers`` parameter in ``tune.run`` when overriding this function.

        .. versionadded:: 0.8.7

        Args:
            result (dict): Training result returned by step().
        """
        if self._implements_method("_log_result") and log_once("_log_result"):
            raise DeprecationWarning(
                "Trainable._log_result is deprecated and is now removed. "
                "Override Trainable.log_result instead.")
        self._result_logger.on_result(result)

    def cleanup(self):
        """Subclasses should override this for any cleanup on stop.

        If any Ray actors are launched in the Trainable (i.e., with a RLlib
        trainer), be sure to kill the Ray actor process here.

        You can kill a Ray actor by calling `actor.__ray_terminate__.remote()`
        on the actor.

        .. versionadded:: 0.8.7
        """
        if self._implements_method("_stop") and log_once("_stop"):
            raise DeprecationWarning(
                "Trainable._stop is deprecated and is now removed. Override "
                "Trainable.cleanup instead.")
        pass

    def _export_model(self, export_formats, export_dir):
        """Subclasses should override this to export model.

        Args:
            export_formats (list): List of formats that should be exported.
            export_dir (str): Directory to place exported models.

        Return:
            A dict that maps ExportFormats to successfully exported models.
        """
        return {}

    def _implements_method(self, key):
        return hasattr(self, key) and callable(getattr(self, key))
Пример #7
0
class Trial(object):
    """A trial object holds the state for one model training run.

    Trials are themselves managed by the TrialRunner class, which implements
    the event loop for submitting trial runs to a Ray cluster.

    Trials start in the PENDING state, and transition to RUNNING once started.
    On error it transitions to ERROR, otherwise TERMINATED on success.
    """

    PENDING = "PENDING"
    RUNNING = "RUNNING"
    PAUSED = "PAUSED"
    TERMINATED = "TERMINATED"
    ERROR = "ERROR"

    def __init__(self,
                 trainable_name,
                 config=None,
                 trial_id=None,
                 local_dir=DEFAULT_RESULTS_DIR,
                 evaluated_params=None,
                 experiment_tag="",
                 resources=None,
                 stopping_criterion=None,
                 checkpoint_freq=0,
                 checkpoint_at_end=False,
                 keep_checkpoints_num=None,
                 checkpoint_score_attr="",
                 export_formats=None,
                 restore_path=None,
                 trial_name_creator=None,
                 loggers=None,
                 sync_to_driver_fn=None,
                 max_failures=0):
        """Initialize a new trial.

        The args here take the same meaning as the command line flags defined
        in ray.tune.config_parser.
        """

        validate_trainable(trainable_name)
        # Trial config
        self.trainable_name = trainable_name
        self.trial_id = Trial.generate_id() if trial_id is None else trial_id
        self.config = config or {}
        self.local_dir = local_dir  # This remains unexpanded for syncing.

        #: Parameters that Tune varies across searches.
        self.evaluated_params = evaluated_params or {}
        self.experiment_tag = experiment_tag
        trainable_cls = self.get_trainable_cls()
        if trainable_cls and hasattr(trainable_cls,
                                     "default_resource_request"):
            default_resources = trainable_cls.default_resource_request(
                self.config)
            if default_resources:
                if resources:
                    raise ValueError(
                        "Resources for {} have been automatically set to {} "
                        "by its `default_resource_request()` method. Please "
                        "clear the `resources_per_trial` option.".format(
                            trainable_cls, default_resources))
                resources = default_resources
        self.resources = resources or Resources(cpu=1, gpu=0)
        self.stopping_criterion = stopping_criterion or {}
        self.loggers = loggers
        self.sync_to_driver_fn = sync_to_driver_fn
        self.verbose = True
        self.max_failures = max_failures

        # Local trial state that is updated during the run
        self.last_result = {}
        self.last_update_time = -float("inf")
        self.checkpoint_freq = checkpoint_freq
        self.checkpoint_at_end = checkpoint_at_end

        self.history = []
        self.keep_checkpoints_num = keep_checkpoints_num
        self._cmp_greater = not checkpoint_score_attr.startswith("min-")
        self.best_checkpoint_attr_value = -float("inf") \
            if self._cmp_greater else float("inf")
        # Strip off "min-" from checkpoint attribute
        self.checkpoint_score_attr = checkpoint_score_attr \
            if self._cmp_greater else checkpoint_score_attr[4:]

        self._checkpoint = Checkpoint(storage=Checkpoint.DISK,
                                      value=restore_path)
        self.export_formats = export_formats
        self.status = Trial.PENDING
        self.logdir = None
        self.runner = None
        self.result_logger = None
        self.last_debug = 0
        self.error_file = None
        self.error_msg = None
        self.num_failures = 0
        self.custom_trial_name = None

        # AutoML fields
        self.results = None
        self.best_result = None
        self.param_config = None
        self.extra_arg = None

        self._nonjson_fields = [
            "_checkpoint",
            "loggers",
            "sync_to_driver_fn",
            "results",
            "best_result",
            "param_config",
            "extra_arg",
        ]
        if trial_name_creator:
            self.custom_trial_name = trial_name_creator(self)

    @classmethod
    def generate_id(cls):
        return str(uuid.uuid1().hex)[:8]

    @classmethod
    def create_logdir(cls, identifier, local_dir):
        local_dir = os.path.expanduser(local_dir)
        if not os.path.exists(local_dir):
            os.makedirs(local_dir)
        return tempfile.mkdtemp(prefix="{}_{}".format(
            identifier[:MAX_LEN_IDENTIFIER], date_str()),
                                dir=local_dir)

    def init_logger(self):
        """Init logger."""

        if not self.result_logger:
            if not self.logdir:
                self.logdir = Trial.create_logdir(str(self), self.local_dir)
            elif not os.path.exists(self.logdir):
                os.makedirs(self.logdir)

            self.result_logger = UnifiedLogger(
                self.config,
                self.logdir,
                trial=self,
                loggers=self.loggers,
                sync_function=self.sync_to_driver_fn)

    def update_resources(self, cpu, gpu, **kwargs):
        """EXPERIMENTAL: Updates the resource requirements.

        Should only be called when the trial is not running.

        Raises:
            ValueError if trial status is running.
        """
        if self.status is Trial.RUNNING:
            raise ValueError("Cannot update resources while Trial is running.")
        self.resources = Resources(cpu, gpu, **kwargs)

    def sync_logger_to_new_location(self, worker_ip):
        """Updates the logger location.

        Also pushes logdir to worker_ip, allowing for cross-node recovery.
        """
        if self.result_logger:
            self.result_logger.sync_results_to_new_location(worker_ip)

    def close_logger(self):
        """Close logger."""

        if self.result_logger:
            self.result_logger.close()
            self.result_logger = None

    def write_error_log(self, error_msg):
        if error_msg and self.logdir:
            self.num_failures += 1  # may be moved to outer scope?
            error_file = os.path.join(self.logdir,
                                      "error_{}.txt".format(date_str()))
            with open(error_file, "w") as f:
                f.write(error_msg)
            self.error_file = error_file
            self.error_msg = error_msg

    def should_stop(self, result):
        """Whether the given result meets this trial's stopping criteria."""

        if result.get(DONE):
            return True

        if callable(self.stopping_criterion):
            return self.stopping_criterion(self.trial_id, result)

        for criteria, stop_value in self.stopping_criterion.items():
            if criteria not in result:
                raise TuneError(
                    "Stopping criteria {} not provided in result {}.".format(
                        criteria, result))
            elif isinstance(criteria, dict):
                raise ValueError(
                    "Stopping criteria is now flattened by default. "
                    "Use forward slashes to nest values `key1/key2/key3`.")
            elif result[criteria] >= stop_value:
                return True
        return False

    def should_checkpoint(self):
        """Whether this trial is due for checkpointing."""
        result = self.last_result or {}

        if result.get(DONE) and self.checkpoint_at_end:
            return True

        if self.checkpoint_freq:
            return result.get(TRAINING_ITERATION,
                              0) % self.checkpoint_freq == 0
        else:
            return False

    def has_checkpoint(self):
        return self._checkpoint.value is not None

    def clear_checkpoint(self):
        self._checkpoint.value = None

    def should_recover(self):
        """Returns whether the trial qualifies for retrying.

        This is if the trial has not failed more than max_failures. Note this
        may return true even when there is no checkpoint, either because
        `self.checkpoint_freq` is `0` or because the trial failed before
        a checkpoint has been made.
        """
        return self.num_failures < self.max_failures or self.max_failures < 0

    def update_last_result(self, result, terminate=False):
        result.update(trial_id=self.trial_id, done=terminate)
        if self.experiment_tag:
            result.update(experiment_tag=self.experiment_tag)
        if self.verbose and (terminate or time.time() - self.last_debug >
                             DEBUG_PRINT_INTERVAL):
            print("Result for {}:".format(self))
            print("  {}".format(pretty_print(result).replace("\n", "\n  ")))
            self.last_debug = time.time()
        self.last_result = result
        self.last_update_time = time.time()
        self.result_logger.on_result(self.last_result)

    def compare_checkpoints(self, attr_mean):
        """Compares two checkpoints based on the attribute attr_mean param.
        Greater than is used by default. If  command-line parameter
        checkpoint_score_attr starts with "min-" less than is used.

        Arguments:
            attr_mean: mean of attribute value for the current checkpoint

        Returns:
            True: when attr_mean is greater than previous checkpoint attr_mean
                  and greater than function is selected
                  when attr_mean is less than previous checkpoint attr_mean and
                  less than function is selected
            False: when attr_mean is not in alignment with selected cmp fn
        """
        if self._cmp_greater and attr_mean > self.best_checkpoint_attr_value:
            return True
        elif (not self._cmp_greater
              and attr_mean < self.best_checkpoint_attr_value):
            return True
        return False

    def get_trainable_cls(self):
        return get_trainable_cls(self.trainable_name)

    def set_verbose(self, verbose):
        self.verbose = verbose

    def is_finished(self):
        return self.status in [Trial.TERMINATED, Trial.ERROR]

    @property
    def node_ip(self):
        return self.last_result.get("node_ip")

    def __repr__(self):
        return str(self)

    def __str__(self):
        """Combines ``env`` with ``trainable_name`` and ``trial_id``.

        Can be overriden with a custom string creator.
        """
        if self.custom_trial_name:
            return self.custom_trial_name

        if "env" in self.config:
            env = self.config["env"]
            if isinstance(env, type):
                env = env.__name__
            identifier = "{}_{}".format(self.trainable_name, env)
        else:
            identifier = self.trainable_name
        identifier += "_" + self.trial_id
        return identifier.replace("/", "_")

    def __getstate__(self):
        """Memento generator for Trial.

        Sets RUNNING trials to PENDING, and flushes the result logger.
        Note this can only occur if the trial holds a DISK checkpoint.
        """
        assert self._checkpoint.storage == Checkpoint.DISK, (
            "Checkpoint must not be in-memory.")
        state = self.__dict__.copy()
        state["resources"] = resources_to_json(self.resources)

        for key in self._nonjson_fields:
            state[key] = binary_to_hex(cloudpickle.dumps(state.get(key)))

        state["runner"] = None
        state["result_logger"] = None
        if self.result_logger:
            self.result_logger.flush()
            state["__logger_started__"] = True
        else:
            state["__logger_started__"] = False
        return copy.deepcopy(state)

    def __setstate__(self, state):
        logger_started = state.pop("__logger_started__")
        state["resources"] = json_to_resources(state["resources"])
        if state["status"] == Trial.RUNNING:
            state["status"] = Trial.PENDING
        for key in self._nonjson_fields:
            state[key] = cloudpickle.loads(hex_to_binary(state[key]))

        self.__dict__.update(state)
        validate_trainable(self.trainable_name)
        if logger_started:
            self.init_logger()
Пример #8
0
class Trial(object):
    """A trial object holds the state for one model training run.

    Trials are themselves managed by the TrialRunner class, which implements
    the event loop for submitting trial runs to a Ray cluster.

    Trials start in the PENDING state, and transition to RUNNING once started.
    On error it transitions to ERROR, otherwise TERMINATED on success.
    """

    PENDING = "PENDING"
    RUNNING = "RUNNING"
    PAUSED = "PAUSED"
    TERMINATED = "TERMINATED"
    ERROR = "ERROR"

    def __init__(self,
                 trainable_name,
                 config=None,
                 trial_id=None,
                 local_dir=DEFAULT_RESULTS_DIR,
                 experiment_tag="",
                 resources=None,
                 stopping_criterion=None,
                 checkpoint_freq=0,
                 checkpoint_at_end=False,
                 keep_checkpoints_num=None,
                 checkpoint_score_attr="",
                 export_formats=None,
                 restore_path=None,
                 upload_dir=None,
                 trial_name_creator=None,
                 loggers=None,
                 sync_function=None,
                 max_failures=0):
        """Initialize a new trial.

        The args here take the same meaning as the command line flags defined
        in ray.tune.config_parser.
        """

        Trial._registration_check(trainable_name)
        # Trial config
        self.trainable_name = trainable_name
        self.config = config or {}
        self.local_dir = os.path.expanduser(local_dir)
        self.experiment_tag = experiment_tag
        self.resources = (
            resources
            or self._get_trainable_cls().default_resource_request(self.config))
        self.stopping_criterion = stopping_criterion or {}
        self.upload_dir = upload_dir
        self.loggers = loggers
        self.sync_function = sync_function
        validate_sync_function(sync_function)
        self.verbose = True
        self.max_failures = max_failures

        # Local trial state that is updated during the run
        self.last_result = {}
        self.last_update_time = -float("inf")
        self.checkpoint_freq = checkpoint_freq
        self.checkpoint_at_end = checkpoint_at_end

        self.history = []
        self.keep_checkpoints_num = keep_checkpoints_num
        self._cmp_greater = not checkpoint_score_attr.startswith("min-")
        self.best_checkpoint_attr_value = -float("inf") \
            if self._cmp_greater else float("inf")
        # Strip off "min-" from checkpoint attribute
        self.checkpoint_score_attr = checkpoint_score_attr \
            if self._cmp_greater else checkpoint_score_attr[4:]

        self._checkpoint = Checkpoint(storage=Checkpoint.DISK,
                                      value=restore_path)
        self.export_formats = export_formats
        self.status = Trial.PENDING
        self.logdir = None
        self.runner = None
        self.result_logger = None
        self.last_debug = 0
        self.trial_id = Trial.generate_id() if trial_id is None else trial_id
        self.error_file = None
        self.num_failures = 0
        self.custom_trial_name = None

        # AutoML fields
        self.results = None
        self.best_result = None
        self.param_config = None
        self.extra_arg = None

        self._nonjson_fields = [
            "_checkpoint",
            "loggers",
            "sync_function",
            "results",
            "best_result",
            "param_config",
            "extra_arg",
        ]
        if trial_name_creator:
            self.custom_trial_name = trial_name_creator(self)

    @classmethod
    def _registration_check(cls, trainable_name):
        if not has_trainable(trainable_name):
            # Make sure rllib agents are registered
            from ray import rllib  # noqa: F401
            if not has_trainable(trainable_name):
                raise TuneError("Unknown trainable: " + trainable_name)

    @classmethod
    def generate_id(cls):
        return binary_to_hex(_random_string())[:8]

    def init_logger(self):
        """Init logger."""

        if not self.result_logger:
            if not os.path.exists(self.local_dir):
                os.makedirs(self.local_dir)
            if not self.logdir:
                self.logdir = tempfile.mkdtemp(prefix="{}_{}".format(
                    str(self)[:MAX_LEN_IDENTIFIER], date_str()),
                                               dir=self.local_dir)
            elif not os.path.exists(self.logdir):
                os.makedirs(self.logdir)

            self.result_logger = UnifiedLogger(
                self.config,
                self.logdir,
                upload_uri=self.upload_dir,
                loggers=self.loggers,
                sync_function=self.sync_function)

    def update_resources(self, cpu, gpu, **kwargs):
        """EXPERIMENTAL: Updates the resource requirements.

        Should only be called when the trial is not running.

        Raises:
            ValueError if trial status is running.
        """
        if self.status is Trial.RUNNING:
            raise ValueError("Cannot update resources while Trial is running.")
        self.resources = Resources(cpu, gpu, **kwargs)

    def sync_logger_to_new_location(self, worker_ip):
        """Updates the logger location.

        Also pushes logdir to worker_ip, allowing for cross-node recovery.
        """
        if self.result_logger:
            self.result_logger.sync_results_to_new_location(worker_ip)

    def close_logger(self):
        """Close logger."""

        if self.result_logger:
            self.result_logger.close()
            self.result_logger = None

    def write_error_log(self, error_msg):
        if error_msg and self.logdir:
            self.num_failures += 1  # may be moved to outer scope?
            error_file = os.path.join(self.logdir,
                                      "error_{}.txt".format(date_str()))
            with open(error_file, "w") as f:
                f.write(error_msg)
            self.error_file = error_file

    def should_stop(self, result):
        """Whether the given result meets this trial's stopping criteria."""

        if result.get(DONE):
            return True

        for criteria, stop_value in self.stopping_criterion.items():
            if criteria not in result:
                raise TuneError(
                    "Stopping criteria {} not provided in result {}.".format(
                        criteria, result))
            if result[criteria] >= stop_value:
                return True

        return False

    def should_checkpoint(self):
        """Whether this trial is due for checkpointing."""
        result = self.last_result or {}

        if result.get(DONE) and self.checkpoint_at_end:
            return True

        if self.checkpoint_freq:
            return result.get(TRAINING_ITERATION,
                              0) % self.checkpoint_freq == 0
        else:
            return False

    def progress_string(self):
        """Returns a progress message for printing out to the console."""

        if not self.last_result:
            return self._status_string()

        def location_string(hostname, pid):
            if hostname == os.uname()[1]:
                return 'pid={}'.format(pid)
            else:
                return '{} pid={}'.format(hostname, pid)

        pieces = [
            '{}'.format(self._status_string()),
            '[{}]'.format(self.resources.summary_string()), '[{}]'.format(
                location_string(self.last_result.get(HOSTNAME),
                                self.last_result.get(PID))),
            '{} s'.format(int(self.last_result.get(TIME_TOTAL_S)))
        ]

        if self.last_result.get(TRAINING_ITERATION) is not None:
            pieces.append('{} iter'.format(
                self.last_result[TRAINING_ITERATION]))

        if self.last_result.get(TIMESTEPS_TOTAL) is not None:
            pieces.append('{} ts'.format(self.last_result[TIMESTEPS_TOTAL]))

        if self.last_result.get(EPISODE_REWARD_MEAN) is not None:
            pieces.append('{} rew'.format(
                format(self.last_result[EPISODE_REWARD_MEAN], '.3g')))

        if self.last_result.get(MEAN_LOSS) is not None:
            pieces.append('{} loss'.format(
                format(self.last_result[MEAN_LOSS], '.3g')))

        if self.last_result.get(MEAN_ACCURACY) is not None:
            pieces.append('{} acc'.format(
                format(self.last_result[MEAN_ACCURACY], '.3g')))

        return ', '.join(pieces)

    def _status_string(self):
        return "{}{}".format(
            self.status, ", {} failures: {}".format(
                self.num_failures, self.error_file) if self.error_file else "")

    def has_checkpoint(self):
        return self._checkpoint.value is not None

    def clear_checkpoint(self):
        self._checkpoint.value = None

    def should_recover(self):
        """Returns whether the trial qualifies for restoring.

        This is if a checkpoint frequency is set and has not failed more than
        max_failures. This may return true even when there may not yet
        be a checkpoint.
        """
        return (self.checkpoint_freq > 0
                and (self.num_failures < self.max_failures
                     or self.max_failures < 0))

    def update_last_result(self, result, terminate=False):
        if terminate:
            result.update(done=True)
        if self.verbose and (terminate or time.time() - self.last_debug >
                             DEBUG_PRINT_INTERVAL):
            print("Result for {}:".format(self))
            print("  {}".format(pretty_print(result).replace("\n", "\n  ")))
            self.last_debug = time.time()
        self.last_result = result
        self.last_update_time = time.time()
        self.result_logger.on_result(self.last_result)

    def compare_checkpoints(self, attr_mean):
        """Compares two checkpoints based on the attribute attr_mean param.
        Greater than is used by default. If  command-line parameter
        checkpoint_score_attr starts with "min-" less than is used.

        Arguments:
            attr_mean: mean of attribute value for the current checkpoint

        Returns:
            True: when attr_mean is greater than previous checkpoint attr_mean
                  and greater than function is selected
                  when attr_mean is less than previous checkpoint attr_mean and
                  less than function is selected
            False: when attr_mean is not in alignment with selected cmp fn
        """
        if self._cmp_greater and attr_mean > self.best_checkpoint_attr_value:
            return True
        elif (not self._cmp_greater
              and attr_mean < self.best_checkpoint_attr_value):
            return True
        return False

    def _get_trainable_cls(self):
        return ray.tune.registry._global_registry.get(
            ray.tune.registry.TRAINABLE_CLASS, self.trainable_name)

    def set_verbose(self, verbose):
        self.verbose = verbose

    def is_finished(self):
        return self.status in [Trial.TERMINATED, Trial.ERROR]

    def __repr__(self):
        return str(self)

    def __str__(self):
        """Combines ``env`` with ``trainable_name`` and ``experiment_tag``.

        Can be overriden with a custom string creator.
        """
        if self.custom_trial_name:
            return self.custom_trial_name

        if "env" in self.config:
            env = self.config["env"]
            if isinstance(env, type):
                env = env.__name__
            identifier = "{}_{}".format(self.trainable_name, env)
        else:
            identifier = self.trainable_name
        if self.experiment_tag:
            identifier += "_" + self.experiment_tag
        return identifier.replace("/", "_")

    def __getstate__(self):
        """Memento generator for Trial.

        Sets RUNNING trials to PENDING, and flushes the result logger.
        Note this can only occur if the trial holds a DISK checkpoint.
        """
        assert self._checkpoint.storage == Checkpoint.DISK, (
            "Checkpoint must not be in-memory.")
        state = self.__dict__.copy()
        state["resources"] = resources_to_json(self.resources)

        for key in self._nonjson_fields:
            state[key] = binary_to_hex(cloudpickle.dumps(state.get(key)))

        state["runner"] = None
        state["result_logger"] = None
        if self.result_logger:
            self.result_logger.flush()
            state["__logger_started__"] = True
        else:
            state["__logger_started__"] = False
        return copy.deepcopy(state)

    def __setstate__(self, state):
        logger_started = state.pop("__logger_started__")
        state["resources"] = json_to_resources(state["resources"])
        if state["status"] == Trial.RUNNING:
            state["status"] = Trial.PENDING
        for key in self._nonjson_fields:
            state[key] = cloudpickle.loads(hex_to_binary(state[key]))

        self.__dict__.update(state)
        Trial._registration_check(self.trainable_name)
        if logger_started:
            self.init_logger()
Пример #9
0
class TrackSession:
    """Manages results for a single session.

    Represents a single Trial in an experiment. This is automatically
    created when using ``tune.run``.

    Attributes:
        trial_name (str): Custom trial name.
        experiment_dir (str): Directory where results for all trials
            are stored. Each session is stored into a unique directory
            inside experiment_dir.
        upload_dir (str): Directory to sync results to.
        trial_config (dict): Parameters that will be logged to disk.
        _tune_reporter (StatusReporter): For rerouting when using Tune.
            Will not instantiate logging if not None.
    """
    def __init__(self,
                 trial_name=None,
                 experiment_dir=None,
                 upload_dir=None,
                 trial_config=None,
                 _tune_reporter=None):
        self._experiment_dir = None
        self._logdir = None
        self._upload_dir = None
        self.trial_config = None
        self._iteration = -1
        self.is_tune_session = bool(_tune_reporter)
        if self.is_tune_session:
            self._logger = _ReporterHook(_tune_reporter)
            self._logdir = _tune_reporter.logdir
            self._trial_name = _tune_reporter.trial_name
            self._trial_id = _tune_reporter.trial_id
        else:
            self._trial_id = Trial.generate_id()
            self._trial_name = trial_name or self._trial_id
            self._initialize_logging(experiment_dir, upload_dir, trial_config)

    def _initialize_logging(self,
                            experiment_dir=None,
                            upload_dir=None,
                            trial_config=None):
        if upload_dir:
            raise NotImplementedError("Upload Dir is not yet implemented.")

        # TODO(rliaw): In other parts of the code, this is `local_dir`.
        if experiment_dir is None:
            experiment_dir = os.path.join(DEFAULT_RESULTS_DIR, "default")

        self._experiment_dir = os.path.expanduser(experiment_dir)

        # TODO(rliaw): Refactor `logdir` to `trial_dir`.
        self._logdir = Trial.create_logdir(self.trial_name,
                                           self._experiment_dir)
        self._upload_dir = upload_dir
        self.trial_config = trial_config or {}

        # misc metadata to save as well
        self.trial_config["trial_id"] = self.trial_id
        self._logger = UnifiedLogger(self.trial_config, self._logdir)

    def log(self, **metrics):
        """Logs all named arguments specified in `metrics`.

        This will log trial metrics locally, and they will be synchronized
        with the driver periodically through ray.

        Arguments:
            metrics: named arguments with corresponding values to log.
        """
        self._iteration += 1
        # TODO: Implement a batching mechanism for multiple calls to `log`
        #     within the same iteration.
        metrics_dict = metrics.copy()
        metrics_dict.update({"trial_id": self.trial_id})

        # TODO: Move Trainable autopopulation to a util function
        metrics_dict.setdefault(TRAINING_ITERATION, self._iteration)
        self._logger.on_result(metrics_dict)

    def close(self):
        """Closes loggers.

        No need to call this when using ``tune.run``.
        """
        self.trial_config["trial_completed"] = True
        self.trial_config["end_time"] = datetime.now().isoformat()
        # TODO(rliaw): Have Tune support updated configs
        self._logger.update_config(self.trial_config)
        self._logger.flush()
        self._logger.close()

    @property
    def logdir(self):
        """Trial logdir (subdir of given experiment directory)"""
        return self._logdir

    @property
    def trial_name(self):
        """Trial name for the corresponding trial of this Trainable"""
        return self._trial_name

    @property
    def trial_id(self):
        """Trial id for the corresponding trial of this Trainable"""
        return self._trial_id
Пример #10
0
class Trial(object):
    """A trial object holds the state for one model training run.

    Trials are themselves managed by the TrialRunner class, which implements
    the event loop for submitting trial runs to a Ray cluster.

    Trials start in the PENDING state, and transition to RUNNING once started.
    On error it transitions to ERROR, otherwise TERMINATED on success.
    """

    PENDING = "PENDING"
    RUNNING = "RUNNING"
    PAUSED = "PAUSED"
    TERMINATED = "TERMINATED"
    ERROR = "ERROR"

    def __init__(self,
                 trainable_name,
                 config=None,
                 trial_id=None,
                 local_dir=DEFAULT_RESULTS_DIR,
                 experiment_tag="",
                 resources=None,
                 stopping_criterion=None,
                 checkpoint_freq=0,
                 checkpoint_at_end=False,
                 restore_path=None,
                 upload_dir=None,
                 trial_name_creator=None,
                 custom_loggers=None,
                 sync_function=None,
                 max_failures=0):
        """Initialize a new trial.

        The args here take the same meaning as the command line flags defined
        in ray.tune.config_parser.
        """

        Trial._registration_check(trainable_name)
        # Trial config
        self.trainable_name = trainable_name
        self.config = config or {}
        self.local_dir = os.path.expanduser(local_dir)
        self.experiment_tag = experiment_tag
        self.resources = (
            resources
            or self._get_trainable_cls().default_resource_request(self.config))
        self.stopping_criterion = stopping_criterion or {}
        self.upload_dir = upload_dir
        self.custom_loggers = custom_loggers
        self.sync_function = sync_function
        validate_sync_function(sync_function)
        self.verbose = True
        self.max_failures = max_failures

        # Local trial state that is updated during the run
        self.last_result = None
        self.last_update_time = -float("inf")
        self.checkpoint_freq = checkpoint_freq
        self.checkpoint_at_end = checkpoint_at_end
        self._checkpoint = Checkpoint(storage=Checkpoint.DISK,
                                      value=restore_path)
        self.status = Trial.PENDING
        self.location = None
        self.logdir = None
        self.result_logger = None
        self.last_debug = 0
        self.trial_id = Trial.generate_id() if trial_id is None else trial_id
        self.error_file = None
        self.num_failures = 0

        self.trial_name = None
        if trial_name_creator:
            self.trial_name = trial_name_creator(self)

    @classmethod
    def _registration_check(cls, trainable_name):
        if not has_trainable(trainable_name):
            # Make sure rllib agents are registered
            from ray import rllib  # noqa: F401
            if not has_trainable(trainable_name):
                raise TuneError("Unknown trainable: " + trainable_name)

    @classmethod
    def generate_id(cls):
        return binary_to_hex(random_string())[:8]

    def init_logger(self):
        """Init logger."""

        if not self.result_logger:
            if not os.path.exists(self.local_dir):
                os.makedirs(self.local_dir)
            if not self.logdir:
                self.logdir = tempfile.mkdtemp(prefix="{}_{}".format(
                    str(self)[:MAX_LEN_IDENTIFIER], date_str()),
                                               dir=self.local_dir)
            elif not os.path.exists(self.logdir):
                os.makedirs(self.logdir)

            self.result_logger = UnifiedLogger(
                self.config,
                self.logdir,
                upload_uri=self.upload_dir,
                custom_loggers=self.custom_loggers,
                sync_function=self.sync_function)

    def close_logger(self):
        """Close logger."""

        if self.result_logger:
            self.result_logger.close()
            self.result_logger = None

    def write_error_log(self, error_msg):
        if error_msg and self.logdir:
            self.num_failures += 1  # may be moved to outer scope?
            error_file = os.path.join(self.logdir,
                                      "error_{}.txt".format(date_str()))
            with open(error_file, "w") as f:
                f.write(error_msg)
            self.error_file = error_file

    def should_stop(self, result):
        """Whether the given result meets this trial's stopping criteria."""

        if result.get(DONE):
            return True

        for criteria, stop_value in self.stopping_criterion.items():
            if criteria not in result:
                raise TuneError(
                    "Stopping criteria {} not provided in result {}.".format(
                        criteria, result))
            if result[criteria] >= stop_value:
                return True

        return False

    def should_checkpoint(self):
        """Whether this trial is due for checkpointing."""
        result = self.last_result or {}

        if result.get(DONE) and self.checkpoint_at_end:
            return True

        if self.checkpoint_freq:
            return result.get(TRAINING_ITERATION,
                              0) % self.checkpoint_freq == 0
        else:
            return False

    def progress_string(self):
        """Returns a progress message for printing out to the console."""

        if self.last_result is None:
            return self._status_string()

        def location_string(hostname, pid):
            if hostname == os.uname()[1]:
                return 'pid={}'.format(pid)
            else:
                return '{} pid={}'.format(hostname, pid)

        pieces = [
            '{} [{}]'.format(
                self._status_string(),
                location_string(self.last_result.get(HOSTNAME),
                                self.last_result.get(PID))),
            '{} s'.format(int(self.last_result.get(TIME_TOTAL_S)))
        ]

        if self.last_result.get(TRAINING_ITERATION) is not None:
            pieces.append('{} iter'.format(
                self.last_result[TRAINING_ITERATION]))

        if self.last_result.get(TIMESTEPS_TOTAL) is not None:
            pieces.append('{} ts'.format(self.last_result[TIMESTEPS_TOTAL]))

        if self.last_result.get("episode_reward_mean") is not None:
            pieces.append('{} rew'.format(
                format(self.last_result["episode_reward_mean"], '.3g')))

        if self.last_result.get("mean_loss") is not None:
            pieces.append('{} loss'.format(
                format(self.last_result["mean_loss"], '.3g')))

        if self.last_result.get("mean_accuracy") is not None:
            pieces.append('{} acc'.format(
                format(self.last_result["mean_accuracy"], '.3g')))

        return ', '.join(pieces)

    def _status_string(self):
        return "{}{}".format(
            self.status, ", {} failures: {}".format(
                self.num_failures, self.error_file) if self.error_file else "")

    def has_checkpoint(self):
        return self._checkpoint.value is not None

    def should_recover(self):
        """Returns whether the trial qualifies for restoring.

        This is if a checkpoint frequency is set and has not failed more than
        max_failures. This may return true even when there may not yet
        be a checkpoint.
        """
        return (self.checkpoint_freq > 0
                and self.num_failures < self.max_failures)

    def update_last_result(self, result, terminate=False):
        if terminate:
            result.update(done=True)
        if self.verbose and (terminate or time.time() - self.last_debug >
                             DEBUG_PRINT_INTERVAL):
            logger.info("Result for {}:".format(self))
            logger.info("  {}".format(
                pretty_print(result).replace("\n", "\n  ")))
            self.last_debug = time.time()
        self.last_result = result
        self.last_update_time = time.time()
        self.result_logger.on_result(self.last_result)

    def _get_trainable_cls(self):
        return ray.tune.registry._global_registry.get(
            ray.tune.registry.TRAINABLE_CLASS, self.trainable_name)

    def set_verbose(self, verbose):
        self.verbose = verbose

    def is_finished(self):
        return self.status in [Trial.TERMINATED, Trial.ERROR]

    def __repr__(self):
        return str(self)

    def __str__(self):
        """Combines ``env`` with ``trainable_name`` and ``experiment_tag``.

        Can be overriden with a custom string creator.
        """
        if self.trial_name:
            return self.trial_name

        if "env" in self.config:
            env = self.config["env"]
            if isinstance(env, type):
                env = env.__name__
            identifier = "{}_{}".format(self.trainable_name, env)
        else:
            identifier = self.trainable_name
        if self.experiment_tag:
            identifier += "_" + self.experiment_tag
        return identifier.replace("/", "_")

    def __getstate__(self):
        """Memento generator for Trial.

        Sets RUNNING trials to PENDING, and flushes the result logger.
        Note this can only occur if the trial holds a DISK checkpoint.
        """
        assert self._checkpoint.storage == Checkpoint.DISK, (
            "Checkpoint must not be in-memory.")
        state = self.__dict__.copy()
        state["resources"] = resources_to_json(self.resources)

        pickle_data = {
            "_checkpoint": self._checkpoint,
            "config": self.config,
            "custom_loggers": self.custom_loggers,
            "sync_function": self.sync_function
        }

        for key, value in pickle_data.items():
            state[key] = binary_to_hex(cloudpickle.dumps(value))

        state["runner"] = None
        state["result_logger"] = None
        if self.status == Trial.RUNNING:
            state["status"] = Trial.PENDING
        if self.result_logger:
            self.result_logger.flush()
            state["__logger_started__"] = True
        else:
            state["__logger_started__"] = False
        return copy.deepcopy(state)

    def __setstate__(self, state):
        logger_started = state.pop("__logger_started__")
        state["resources"] = json_to_resources(state["resources"])
        for key in [
                "_checkpoint", "config", "custom_loggers", "sync_function"
        ]:
            state[key] = cloudpickle.loads(hex_to_binary(state[key]))

        self.__dict__.update(state)
        Trial._registration_check(self.trainable_name)
        if logger_started:
            self.init_logger()
Пример #11
0
class Trainable(object):
    """Abstract class for trainable models, functions, etc.

    A call to ``train()`` on a trainable will execute one logical iteration of
    training. As a rule of thumb, the execution time of one train call should
    be large enough to avoid overheads (i.e. more than a few seconds), but
    short enough to report progress periodically (i.e. at most a few minutes).

    Calling ``save()`` should save the training state of a trainable to disk,
    and ``restore(path)`` should restore a trainable to the given state.

    Generally you only need to implement ``_setup``, ``_train``,
    ``_save``, and ``_restore`` when subclassing Trainable.

    Other implementation methods that may be helpful to override are
    ``_log_result``, ``reset_config``, ``_stop``, and ``_export_model``.

    When using Tune, Tune will convert this class into a Ray actor, which
    runs on a separate process. Tune will also change the current working
    directory of this process to `self.logdir`.

    """
    def __init__(self, config=None, logger_creator=None):
        """Initialize an Trainable.

        Sets up logging and points ``self.logdir`` to a directory in which
        training outputs should be placed.

        Subclasses should prefer defining ``_setup()`` instead of overriding
        ``__init__()`` directly.

        Args:
            config (dict): Trainable-specific configuration data. By default
                will be saved as ``self.config``.
            logger_creator (func): Function that creates a ray.tune.Logger
                object. If unspecified, a default logger is created.
        """

        self._experiment_id = uuid.uuid4().hex
        self.config = config or {}

        if logger_creator:
            self._result_logger = logger_creator(self.config)
            self._logdir = self._result_logger.logdir
        else:
            logdir_prefix = datetime.today().strftime("%Y-%m-%d_%H-%M-%S")
            if not os.path.exists(DEFAULT_RESULTS_DIR):
                os.makedirs(DEFAULT_RESULTS_DIR)
            self._logdir = tempfile.mkdtemp(prefix=logdir_prefix,
                                            dir=DEFAULT_RESULTS_DIR)
            self._result_logger = UnifiedLogger(self.config,
                                                self._logdir,
                                                loggers=None)

        self._iteration = 0
        self._time_total = 0.0
        self._timesteps_total = None
        self._episodes_total = None
        self._time_since_restore = 0.0
        self._timesteps_since_restore = 0
        self._iterations_since_restore = 0
        self._restored = False

        start_time = time.time()
        self._setup(copy.deepcopy(self.config))
        setup_time = time.time() - start_time
        if setup_time > SETUP_TIME_THRESHOLD:
            logger.info("_setup took {:.3f} seconds. If your trainable is "
                        "slow to initialize, consider setting "
                        "reuse_actors=True to reduce actor creation "
                        "overheads.".format(setup_time))
        self._local_ip = ray.services.get_node_ip_address()
        log_sys_usage = self.config.get("log_sys_usage", False)
        self._monitor = UtilMonitor(start=log_sys_usage)

    @classmethod
    def default_resource_request(cls, config):
        """Returns the resource requirement for the given configuration.

        This can be overriden by sub-classes to set the correct trial resource
        allocation, so the user does not need to.

        Example:
            >>> def default_resource_request(cls, config):
            >>>     return Resources(
            >>>         cpu=0,
            >>>         gpu=0,
            >>>         extra_cpu=config["workers"],
            >>>         extra_gpu=int(config["use_gpu"]) * config["workers"])
        """

        return None

    @classmethod
    def resource_help(cls, config):
        """Returns a help string for configuring this trainable's resources."""

        return ""

    def current_ip(self):
        logger.warning("Getting current IP.")
        self._local_ip = ray.services.get_node_ip_address()
        return self._local_ip

    def train(self):
        """Runs one logical iteration of training.

        Subclasses should override ``_train()`` instead to return results.
        This class automatically fills the following fields in the result:

            `done` (bool): training is terminated. Filled only if not provided.

            `time_this_iter_s` (float): Time in seconds this iteration
            took to run. This may be overriden in order to override the
            system-computed time difference.

            `time_total_s` (float): Accumulated time in seconds for this
            entire experiment.

            `experiment_id` (str): Unique string identifier
            for this experiment. This id is preserved
            across checkpoint / restore calls.

            `training_iteration` (int): The index of this
            training iteration, e.g. call to train(). This is incremented
            after `_train()` is called.

            `pid` (str): The pid of the training process.

            `date` (str): A formatted date of when the result was processed.

            `timestamp` (str): A UNIX timestamp of when the result
            was processed.

            `hostname` (str): Hostname of the machine hosting the training
            process.

            `node_ip` (str): Node ip of the machine hosting the training
            process.

        Returns:
            A dict that describes training progress.
        """
        start = time.time()
        result = self._train()
        assert isinstance(result, dict), "_train() needs to return a dict."

        # We do not modify internal state nor update this result if duplicate.
        if RESULT_DUPLICATE in result:
            return result

        result = result.copy()

        self._iteration += 1
        self._iterations_since_restore += 1

        if result.get(TIME_THIS_ITER_S) is not None:
            time_this_iter = result[TIME_THIS_ITER_S]
        else:
            time_this_iter = time.time() - start
        self._time_total += time_this_iter
        self._time_since_restore += time_this_iter

        result.setdefault(DONE, False)

        # self._timesteps_total should only be tracked if increments provided
        if result.get(TIMESTEPS_THIS_ITER) is not None:
            if self._timesteps_total is None:
                self._timesteps_total = 0
            self._timesteps_total += result[TIMESTEPS_THIS_ITER]
            self._timesteps_since_restore += result[TIMESTEPS_THIS_ITER]

        # self._episodes_total should only be tracked if increments provided
        if result.get(EPISODES_THIS_ITER) is not None:
            if self._episodes_total is None:
                self._episodes_total = 0
            self._episodes_total += result[EPISODES_THIS_ITER]

        # self._timesteps_total should not override user-provided total
        result.setdefault(TIMESTEPS_TOTAL, self._timesteps_total)
        result.setdefault(EPISODES_TOTAL, self._episodes_total)
        result.setdefault(TRAINING_ITERATION, self._iteration)

        # Provides auto-filled neg_mean_loss for avoiding regressions
        if result.get("mean_loss"):
            result.setdefault("neg_mean_loss", -result["mean_loss"])

        now = datetime.today()
        result.update(experiment_id=self._experiment_id,
                      date=now.strftime("%Y-%m-%d_%H-%M-%S"),
                      timestamp=int(time.mktime(now.timetuple())),
                      time_this_iter_s=time_this_iter,
                      time_total_s=self._time_total,
                      pid=os.getpid(),
                      hostname=os.uname()[1],
                      node_ip=self._local_ip,
                      config=self.config,
                      time_since_restore=self._time_since_restore,
                      timesteps_since_restore=self._timesteps_since_restore,
                      iterations_since_restore=self._iterations_since_restore)

        monitor_data = self._monitor.get_data()
        if monitor_data:
            result.update(monitor_data)

        self._log_result(result)

        return result

    def save(self, checkpoint_dir=None):
        """Saves the current model state to a checkpoint.

        Subclasses should override ``_save()`` instead to save state.
        This method dumps additional metadata alongside the saved path.

        Args:
            checkpoint_dir (str): Optional dir to place the checkpoint.

        Returns:
            Checkpoint path or prefix that may be passed to restore().
        """
        checkpoint_dir = os.path.join(checkpoint_dir or self.logdir,
                                      "checkpoint_{}".format(self._iteration))

        if not os.path.exists(checkpoint_dir):
            os.makedirs(checkpoint_dir)
        checkpoint = self._save(checkpoint_dir)
        saved_as_dict = False
        if isinstance(checkpoint, string_types):
            if not checkpoint.startswith(checkpoint_dir):
                raise ValueError(
                    "The returned checkpoint path must be within the "
                    "given checkpoint dir {}: {}".format(
                        checkpoint_dir, checkpoint))
            checkpoint_path = checkpoint
        elif isinstance(checkpoint, dict):
            saved_as_dict = True
            checkpoint_path = os.path.join(checkpoint_dir, "checkpoint")
            with open(checkpoint_path, "wb") as f:
                pickle.dump(checkpoint, f)
        else:
            raise ValueError("Returned unexpected type {}. "
                             "Expected str or dict.".format(type(checkpoint)))

        with open(checkpoint_path + ".tune_metadata", "wb") as f:
            pickle.dump(
                {
                    "experiment_id": self._experiment_id,
                    "iteration": self._iteration,
                    "timesteps_total": self._timesteps_total,
                    "time_total": self._time_total,
                    "episodes_total": self._episodes_total,
                    "saved_as_dict": saved_as_dict,
                    "ray_version": ray.__version__,
                }, f)
        return checkpoint_path

    def save_to_object(self):
        """Saves the current model state to a Python object.

        It also saves to disk but does not return the checkpoint path.

        Returns:
            Object holding checkpoint data.
        """
        tmpdir = tempfile.mkdtemp("save_to_object", dir=self.logdir)
        checkpoint_path = self.save(tmpdir)
        # Save all files in subtree.
        data = {}
        for basedir, _, file_names in os.walk(tmpdir):
            for file_name in file_names:
                path = os.path.join(basedir, file_name)

                with open(path, "rb") as f:
                    data[os.path.relpath(path, tmpdir)] = f.read()

        out = io.BytesIO()
        data_dict = pickle.dumps({
            "checkpoint_name":
            os.path.relpath(checkpoint_path, tmpdir),
            "data":
            data,
        })
        if len(data_dict) > 10e6:  # getting pretty large
            logger.info("Checkpoint size is {} bytes".format(len(data_dict)))
        out.write(data_dict)
        shutil.rmtree(tmpdir)
        return out.getvalue()

    def restore(self, checkpoint_path):
        """Restores training state from a given model checkpoint.

        These checkpoints are returned from calls to save().

        Subclasses should override ``_restore()`` instead to restore state.
        This method restores additional metadata saved with the checkpoint.
        """
        with open(checkpoint_path + ".tune_metadata", "rb") as f:
            metadata = pickle.load(f)
        self._experiment_id = metadata["experiment_id"]
        self._iteration = metadata["iteration"]
        self._timesteps_total = metadata["timesteps_total"]
        self._time_total = metadata["time_total"]
        self._episodes_total = metadata["episodes_total"]
        saved_as_dict = metadata["saved_as_dict"]
        if saved_as_dict:
            with open(checkpoint_path, "rb") as loaded_state:
                checkpoint_dict = pickle.load(loaded_state)
            checkpoint_dict.update(tune_checkpoint_path=checkpoint_path)
            self._restore(checkpoint_dict)
        else:
            self._restore(checkpoint_path)
        self._time_since_restore = 0.0
        self._timesteps_since_restore = 0
        self._iterations_since_restore = 0
        self._restored = True
        logger.info("Restored from checkpoint: %s", checkpoint_path)
        state = {
            "_iteration": self._iteration,
            "_timesteps_total": self._timesteps_total,
            "_time_total": self._time_total,
            "_episodes_total": self._episodes_total,
        }
        logger.info("Current state after restoring: {}".format(state))

    def restore_from_object(self, obj):
        """Restores training state from a checkpoint object.

        These checkpoints are returned from calls to save_to_object().
        """
        info = pickle.loads(obj)
        data = info["data"]
        tmpdir = tempfile.mkdtemp("restore_from_object", dir=self.logdir)
        checkpoint_path = os.path.join(tmpdir, info["checkpoint_name"])

        for relpath_name, file_contents in data.items():
            path = os.path.join(tmpdir, relpath_name)

            # This may be a subdirectory, hence not just using tmpdir
            if not os.path.exists(os.path.dirname(path)):
                os.makedirs(os.path.dirname(path))
            with open(path, "wb") as f:
                f.write(file_contents)

        self.restore(checkpoint_path)
        shutil.rmtree(tmpdir)

    def export_model(self, export_formats, export_dir=None):
        """Exports model based on export_formats.

        Subclasses should override _export_model() to actually
        export model to local directory.

        Args:
            export_formats (list): List of formats that should be exported.
            export_dir (str): Optional dir to place the exported model.
                Defaults to self.logdir.

        Returns:
            A dict that maps ExportFormats to successfully exported models.
        """
        export_dir = export_dir or self.logdir
        return self._export_model(export_formats, export_dir)

    def reset_config(self, new_config):
        """Resets configuration without restarting the trial.

        This method is optional, but can be implemented to speed up algorithms
        such as PBT, and to allow performance optimizations such as running
        experiments with reuse_actors=True. Note that self.config need to
        be updated to reflect the latest parameter information in Ray logs.

        Args:
            new_config (dir): Updated hyperparameter configuration
                for the trainable.

        Returns:
            True if reset was successful else False.
        """
        return False

    def stop(self):
        """Releases all resources used by this trainable."""
        self._result_logger.flush()
        self._result_logger.close()
        self._stop()

    @property
    def logdir(self):
        """Directory of the results and checkpoints for this Trainable.

        Tune will automatically sync this folder with the driver if execution
        is distributed.

        Note that the current working directory will also be changed to this.

        """
        return self._logdir

    @property
    def iteration(self):
        """Current training iteration.

        This value is automatically incremented every time `train()` is called
        and is automatically inserted into the training result dict.

        """
        return self._iteration

    def get_config(self):
        """Returns configuration passed in by Tune."""
        return self.config

    def _train(self):
        """Subclasses should override this to implement train().

        The return value will be automatically passed to the loggers. Users
        can also return `tune.result.DONE` or `tune.result.SHOULD_CHECKPOINT`
        as a key to manually trigger termination or checkpointing of this
        trial. Note that manual checkpointing only works when subclassing
        Trainables.

        Returns:
            A dict that describes training progress.

        """

        raise NotImplementedError

    def _save(self, tmp_checkpoint_dir):
        """Subclasses should override this to implement ``save()``.

        Warning:
            Do not rely on absolute paths in the implementation of ``_save``
            and ``_restore``.

        Use ``validate_save_restore`` to catch ``_save``/``_restore`` errors
        before execution.

        >>> from ray.tune.util import validate_save_restore
        >>> validate_save_restore(MyTrainableClass)
        >>> validate_save_restore(MyTrainableClass, use_object_store=True)

        Args:
            tmp_checkpoint_dir (str): The directory where the checkpoint
                file must be stored. In a Tune run, if the trial is paused,
                the provided path may be temporary and moved.

        Returns:
            A dict or string. If string, the return value is expected to be
            prefixed by `tmp_checkpoint_dir`. If dict, the return value will
            be automatically serialized by Tune and passed to `_restore()`.

        Examples:
            >>> print(trainable1._save("/tmp/checkpoint_1"))
            "/tmp/checkpoint_1/my_checkpoint_file"
            >>> print(trainable2._save("/tmp/checkpoint_2"))
            {"some": "data"}

            >>> trainable._save("/tmp/bad_example")
            "/tmp/NEW_CHECKPOINT_PATH/my_checkpoint_file" # This will error.
        """

        raise NotImplementedError

    def _restore(self, checkpoint):
        """Subclasses should override this to implement restore().

        Warning:
            In this method, do not rely on absolute paths. The absolute
            path of the checkpoint_dir used in ``_save`` may be changed.

        If ``_save`` returned a prefixed string, the prefix of the checkpoint
        string returned by ``_save`` may be changed. This is because trial
        pausing depends on temporary directories.

        The directory structure under the checkpoint_dir provided to ``_save``
        is preserved.

        See the example below.

        .. code-block:: python

            class Example(Trainable):
                def _save(self, checkpoint_path):
                    print(checkpoint_path)
                    return os.path.join(checkpoint_path, "my/check/point")

                def _restore(self, checkpoint):
                    print(checkpoint)

            >>> trainer = Example()
            >>> obj = trainer.save_to_object()  # This is used when PAUSED.
            <logdir>/tmpc8k_c_6hsave_to_object/checkpoint_0/my/check/point
            >>> trainer.restore_from_object(obj)  # Note the different prefix.
            <logdir>/tmpb87b5axfrestore_from_object/checkpoint_0/my/check/point


        Args:
            checkpoint (str|dict): If dict, the return value is as
                returned by `_save`. If a string, then it is a checkpoint path
                that may have a different prefix than that returned by `_save`.
                The directory structure underneath the `checkpoint_dir`
                `_save` is preserved.
        """

        raise NotImplementedError

    def _setup(self, config):
        """Subclasses should override this for custom initialization.

        Args:
            config (dict): Hyperparameters and other configs given.
                Copy of `self.config`.
        """
        pass

    def _log_result(self, result):
        """Subclasses can optionally override this to customize logging.

        Args:
            result (dict): Training result returned by _train().
        """
        self._result_logger.on_result(result)

    def _stop(self):
        """Subclasses should override this for any cleanup on stop.

        If any Ray actors are launched in the Trainable (i.e., with a RLlib
        trainer), be sure to kill the Ray actor process here.

        You can kill a Ray actor by calling `actor.__ray_terminate__.remote()`
        on the actor.
        """
        pass

    def _export_model(self, export_formats, export_dir):
        """Subclasses should override this to export model.

        Args:
            export_formats (list): List of formats that should be exported.
            export_dir (str): Directory to place exported models.

        Return:
            A dict that maps ExportFormats to successfully exported models.
        """
        return {}