def asyncgen_manager(): if hasattr(sys, 'get_asyncgen_hooks'): old_asyncgen_hooks = sys.get_asyncgen_hooks() def _init_async_gen(agen): if not is_safe_generator(agen) and not finalize.is_finalized(agen): # Inspect the code of the generator to see if it might be safe raise RuntimeError("Async generator with async finalization must be wrapped by\n" "async with curio.meta.finalize(agen) as agen:\n" " async for n in agen:\n" " ...\n" "See PEP 533 for further discussion.") sys.set_asyncgen_hooks(_init_async_gen) try: yield finally: if hasattr(sys, 'get_asyncgen_hooks'): sys.set_asyncgen_hooks(*old_asyncgen_hooks)
def test_asyncgen_hooks(self): old = sys.get_asyncgen_hooks() self.assertIsNone(old.firstiter) self.assertIsNone(old.finalizer) firstiter = lambda *a: None sys.set_asyncgen_hooks(firstiter=firstiter) hooks = sys.get_asyncgen_hooks() self.assertIs(hooks.firstiter, firstiter) self.assertIs(hooks[0], firstiter) self.assertIs(hooks.finalizer, None) self.assertIs(hooks[1], None) finalizer = lambda *a: None sys.set_asyncgen_hooks(finalizer=finalizer) hooks = sys.get_asyncgen_hooks() self.assertIs(hooks.firstiter, firstiter) self.assertIs(hooks[0], firstiter) self.assertIs(hooks.finalizer, finalizer) self.assertIs(hooks[1], finalizer) sys.set_asyncgen_hooks(*old) cur = sys.get_asyncgen_hooks() self.assertIsNone(cur.firstiter) self.assertIsNone(cur.finalizer)
def end(self, session): super().end(session) self._update_hook_list() # Non-coroutine hooks are done now. Anything they wanted to do, they did in end() self._remove_non_coroutine_hooks() # However, coroutine hooks cannot proceed independently, we must loop them manually # so that they can make progress in parallel. # Therefore, if some hooks' coroutines haven't finished and would like to await more runs, # we let them do this by looping manually. self._finish_hooks(session) # The coroutines have finished, but there may be some asynchronous generators (asyncgens) # somewhere that haven't been cleaned up yet. # Moreover, additional asyncgens may be created when we finish these ones, so we must loop # here. while self._alive_asyncgens: for asyncgen in self._alive_asyncgens: self._finalize_asyncgen(asyncgen) self._update_hook_list() self._finish_hooks(session) # Now all asyncgens are finished. # We are ending the loop, hence we are no longer in charge of finalizing new asyncgens. if self._original_sys_asyncgen_hooks: sys.set_asyncgen_hooks(*self._original_sys_asyncgen_hooks) logging.debug('Ending hook 6.')
def run_forever_35_36(self): # from Python 3.5/3.6 asyncio.base_events self._check_closed() old_thread_id = self._thread_id old_running_loop = events._get_running_loop() self._set_coroutine_wrapper(self._debug) self._thread_id = threading.get_ident() if self._asyncgens is not None: old_agen_hooks = sys.get_asyncgen_hooks() sys.set_asyncgen_hooks(firstiter=self._asyncgen_firstiter_hook, finalizer=self._asyncgen_finalizer_hook) try: events._set_running_loop(self) while True: self._run_once() if self._stopping: break finally: self._stopping = False self._thread_id = old_thread_id events._set_running_loop(old_running_loop) self._set_coroutine_wrapper(False) if self._asyncgens is not None: sys.set_asyncgen_hooks(*old_agen_hooks)
def test_asyncgen_hooks(self): old = sys.get_asyncgen_hooks() self.assertIsNone(old.firstiter) self.assertIsNone(old.finalizer) firstiter = lambda *a: None sys.set_asyncgen_hooks(firstiter=firstiter) hooks = sys.get_asyncgen_hooks() self.assertIs(hooks.firstiter, firstiter) self.assertIs(hooks[0], firstiter) self.assertIs(hooks.finalizer, None) self.assertIs(hooks[1], None) finalizer = lambda *a: None sys.set_asyncgen_hooks(finalizer=finalizer) hooks = sys.get_asyncgen_hooks() self.assertIs(hooks.firstiter, firstiter) self.assertIs(hooks[0], firstiter) self.assertIs(hooks.finalizer, finalizer) self.assertIs(hooks[1], finalizer) sys.set_asyncgen_hooks(*old) cur = sys.get_asyncgen_hooks() self.assertIsNone(cur.firstiter) self.assertIsNone(cur.finalizer)
def stop_slave_loop(self): asyncio.events._set_running_loop(None) self._set_coroutine_origin_tracking(False) sys.set_asyncgen_hooks(*self._old_agen_hooks)
def run_forever(self, app_context): print("run_forever") """Set up the asyncio event loop, integrate it with the Winforms event loop, and start the application. This largely duplicates the setup behavior of the default Proactor run_forever implementation. :param app_context: The WinForms.ApplicationContext instance controlling the lifecycle of the app. """ # Python 3.8 added an implementation of run_forever() in # ProactorEventLoop. The only part that actually matters is the # refactoring that moved the initial call to stage _loop_self_reading; # it now needs to be created as part of run_forever; otherwise the # event loop locks up, because there won't be anything for the # select call to process. if sys.version_info >= (3, 8): self.call_soon(self._loop_self_reading) # Remember the application context. self.app_context = app_context # Register a custom user window message. self.msg_id = user32.RegisterWindowMessageA("Python asyncio tick") # Add a message filter to listen for the asyncio tick message # FIXME: Actually install the message filter. # msg_filter = AsyncIOTickMessageFilter(self, self.msg_id) # WinForms.Application.AddMessageFilter(msg_filter) # Setup the Proactor. # The code between the following markers should be exactly the same as # the official CPython implementation, up to the start of the # `while True:` part of run_forever() (see BaseEventLoop.run_forever() # in Lib/ascynio/base_events.py) # === START BaseEventLoop.run_forever() setup === self._check_closed() if self.is_running(): raise RuntimeError('This event loop is already running') if events._get_running_loop() is not None: raise RuntimeError( 'Cannot run the event loop while another loop is running') self._set_coroutine_origin_tracking(self._debug) self._thread_id = threading.get_ident() try: self._old_agen_hooks = sys.get_asyncgen_hooks() sys.set_asyncgen_hooks(firstiter=self._asyncgen_firstiter_hook, finalizer=self._asyncgen_finalizer_hook) except AttributeError: # Python < 3.6 didn't have sys.get_asyncgen_hooks(); # No action required for those versions. pass events._set_running_loop(self) # === END BaseEventLoop.run_forever() setup === # Rather than going into a `while True:` loop, we're going to use the # Winforms event loop to queue a tick() message that will cause a # single iteration of the asyncio event loop to be executed. Each time # we do this, we queue *another* tick() message in 5ms time. In this # way, we'll get a continuous stream of tick() calls, without blocking # the Winforms event loop. # Queue the first asyncio tick. self.enqueue_tick() # Start the Winforms event loop. WinForms.Application.Run(self.app_context)
# sys.settrace(test) print("xxxxxxxxxxxxxxxx", sys.gettrace()) print(sys.getwindowsversion()) def firstiter(): print('from firstiter.') def finalizer(): print('from finalizer.') sys.set_asyncgen_hooks(firstiter, finalizer) print(sys.get_asyncgen_hooks()) print(sys.get_coroutine_origin_tracking_depth()) print(sys.hash_info) print(sys.hexversion) print(sys.implementation) print(sys.int_info) print(sys.__interactivehook__) s1 = sys.intern('hello!哈哈') s2 = 'hello!哈哈'
def _run_coro(self): ''' Run the kernel ''' assert self._selector is not None, 'Kernel has been shut down' njobs = 0 # Motto: "What happens in the kernel stays in the kernel" # ---- Kernel State current = None # Currently running task selector = self._selector # Event selector ready = self._ready # Ready queue tasks = self._tasks # Task table sleeping = self._sleeping # Sleeping task queue wake_queue = self._wake_queue # External wake queue warn_if_task_blocks_for = self._warn_if_task_blocks_for # ---- Bound methods selector_register = selector.register selector_unregister = selector.unregister selector_modify = selector.modify selector_select = selector.select selector_getkey = selector.get_key ready_popleft = ready.popleft ready_append = ready.append time_monotonic = time.monotonic _wake = self._wake # ---- In-kernel task used for processing signals and futures # Initialize the loopback socket and launch the kernel task if needed def _init_loopback_task(): self._init_loopback() task = Task(_kernel_task(), taskid=0, daemon=True) _reschedule_task(task) self._kernel_task_id = task.id self._tasks[task.id] = task # Internal task that monitors the loopback socket--allowing the kernel to # awake for non-I/O events. Also processes incoming signals. This only # launches if needed to wait for external events (futures, signals, etc.) async def _kernel_task(): wake_queue_popleft = wake_queue.popleft wait_sock = self._wait_sock while True: await _read_wait(wait_sock) data = wait_sock.recv(1000) # Process any waking tasks. These are tasks that have been awakened # externally to the event loop (e.g., by separate threads, Futures, etc.) while wake_queue: task, future = wake_queue_popleft() # If the future associated with wakeup no longer matches # the future stored on the task, wakeup is abandoned. # It means that a timeout or cancellation event occurred # in the time interval between the call to self._wake() # and the subsequent processing of the waking task if future and task.future is not future: continue task.future = None task.state = 'READY' task.cancel_func = None ready_append(task) # Any non-null bytes received here are assumed to be received signals. # See if there are any pending signal sets and unblock if needed if not self._signal_sets: continue sigs = (n for n in data if n in self._signal_sets) for signo in sigs: for sigset in self._signal_sets[signo]: sigset.pending.append(signo) if sigset.waiting: _reschedule_task(sigset.waiting, value=signo) sigset.waiting = None # ---- Task Support Functions # Create a new task. Putting it on the ready queue def _new_task(coro, daemon=False): nonlocal njobs task = Task(coro, daemon) tasks[task.id] = task if not daemon: njobs += 1 _reschedule_task(task) return task # Reschedule a task, putting it back on the ready queue so that it can run. # value and exc specify a value or exception to send into the underlying # coroutine when it is rescheduled. def _reschedule_task(task, value=None, exc=None): ready_append(task) task.next_value = value task.next_exc = exc task.state = 'READY' task.cancel_func = None # Cleanup task. This is called after the underlying coroutine has # terminated. value and exc give the return value or exception of # the coroutine. This wakes any tasks waiting to join. def _cleanup_task(task, value=None, exc=None): nonlocal main_task, main_value, main_exc, njobs task.next_value = value task.next_exc = exc task.timeout = None if not task.daemon: njobs -= 1 if task.joining: for wtask in task.joining.pop(len(task.joining)): _reschedule_task(wtask) task.joining = None task.terminated = True del tasks[task.id] # If the task just cleaned up was the main task, we set # its return values. This will cause the kernel loop to yield if task == main_task: main_value = value main_exc = exc main_task = None # Set a timeout or sleep event on the current task def _set_timeout(clock, sleep_type='timeout'): item = (clock, current.id, sleep_type) heapq.heappush(sleeping, item) setattr(current, sleep_type, clock) # ---- I/O Support functions def _register_event(fileobj, event, task): try: key = selector_getkey(fileobj) mask, (rtask, wtask) = key.events, key.data if event == EVENT_READ and rtask: raise CurioError( "Multiple tasks can't wait to read on the same file descriptor %r" % fileobj) if event == EVENT_WRITE and wtask: raise CurioError( "Multiple tasks can't wait to write on the same file descriptor %r" % fileobj) selector_modify(fileobj, mask | event, (task, wtask) if event == EVENT_READ else (rtask, task)) except KeyError: selector_register(fileobj, event, (task, None) if event == EVENT_READ else (None, task)) def _unregister_event(fileobj, event): key = selector_getkey(fileobj) mask, (rtask, wtask) = key.events, key.data mask &= ~event if not mask: selector_unregister(fileobj) else: selector_modify(fileobj, mask, (None, wtask) if event == EVENT_READ else (rtask, None)) # ---- Traps # # These implement the low-level functionality that is # triggered by coroutines. They are never invoked directly # and there is no public API outside the kernel. Instead, # coroutines use a statement such as # # yield (_blocking_trap_io, sock, EVENT_READ, 'READ_WAIT') # # to invoke a specific trap. # # There are two calling conventions we use for implementing these: # # 1) Blocking trap handlers return the new values for # # (task.state, task.cancel_func) # # They don't have any way to pass values/exceptions back to the # invoker. # # 2) Nonblocking trap handlers act like regular function calls -- whatever # they return or raise will be passed back to the invoker. # Wait for I/O @blocking def _trap_io(fileobj, event, state): # See comment about deferred unregister in run(). If the requested # I/O operation is *different* than the last I/O operation that was # performed by the task, we need to unregister the last I/O resource used # and register a new one with the selector. if current._last_io != (fileobj, event): if current._last_io: _unregister_event(*current._last_io) try: _register_event(fileobj, event, current) except CurioError as e: _reschedule_task(current, exc=e) return (current.state, None) # This step indicates that we have managed any deferred I/O management # for the task. Otherwise the run() method will perform an unregistration step. current._last_io = None return (state, lambda: _unregister_event(fileobj, event)) # Wait on a Future @blocking def _trap_future_wait(future, event): if self._kernel_task_id is None: _init_loopback_task() current.future = future # Discussion: Each task records the future that it is # currently waiting on. The completion callback below only # attempts to wake the task if its stored Future is exactly # the same one that was stored above. Due to support for # cancellation and timeouts, it's possible that a task might # abandon its attempt to wait for a Future and go on to # perform other operations, including waiting for different # Future in the future (got it?). However, a running thread # or process still might go on to eventually complete the # earlier work. In that case, it will trigger the callback, # find that the task's current Future is now different, and # discard the result. future.add_done_callback( lambda fut, task=current: _wake(task, fut)) # An optional threading.Event object can be passed and set to # start a worker thread. This makes it possible to have a lock-free # Future implementation where worker threads only start after the # callback function has been set above. if event: event.set() return ('FUTURE_WAIT', lambda task=current: setattr(task, 'future', future.cancel() and None)) # Add a new task to the kernel @nonblocking def _trap_spawn(coro, daemon): task = _new_task( coro, daemon | current.daemon) # Inherits daemonic status from parent task.parentid = current.id _copy_tasklocal(current, task) return task # Reschedule one or more tasks from a kernel sync @nonblocking def _trap_ksync_reschedule_tasks(ksync, n): tasks = ksync.pop(n) for task in tasks: _reschedule_task(task) # Trap that returns a function for rescheduling tasks from synchronous code @nonblocking def _trap_ksync_reschedule_function(ksync): def _reschedule(n): tasks = ksync.pop(n) for task in tasks: _reschedule_task(task) return _reschedule # Join with a task @blocking def _trap_join_task(task): if task.terminated: return _trap_sleep(0, False) else: if task.joining is None: task.joining = KSyncQueue() return _trap_wait_ksync(task.joining, 'TASK_JOIN') # Cancel a task @nonblocking def _trap_cancel_task(task, exc=TaskCancelled, val=None): if task.cancelled: return task.cancelled = True # Cancelling a task also cancels any currently pending timeout. # If a task is being cancelled, the delivery of a timeout is # somewhat immaterial--the task is already being cancelled. task.timeout = None # Set the cancellation exception task.cancel_pending = exc(exc.__name__ if val is None else val) # If the task doesn't allow the delivery of a cancellation exception right now # we're done. It's up to the task to check for it later if not task.allow_cancel: return # If the task doesn't have a cancellation function set, it means the task # is on the ready-queue. It's not safe to deliver a cancellation exception # to it right now. Instead, we simply return. It will get cancelled # the next time it performs a blocking operation if not task.cancel_func: return # Cancel and reschedule the task task.cancel_func() _reschedule_task(task, exc=task.cancel_pending) task.cancel_pending = None # Wait on a queue @blocking def _trap_wait_ksync(ksync, state): return (state, ksync.add(current)) # Sleep for a specified period. Returns value of monotonic clock. # absolute flag indicates whether or not an absolute or relative clock # interval has been provided @blocking def _trap_sleep(clock, absolute): # We used to have a special case where sleep periods <= 0 would # simply reschedule the task to the end of the ready queue without # actually putting it on the sleep queue first. But this meant # that if a task looped while calling sleep(0), it would allow # other *ready* tasks to run, but block ever checking for I/O or # timeouts, so sleeping tasks would never wake up. That's not what # we want; sleep(0) should mean "please give other stuff a chance # to run". So now we always go through the whole sleep machinery. if not absolute: clock += time_monotonic() _set_timeout(clock, 'sleep') return ('TIME_SLEEP', lambda task=current: setattr(task, 'sleep', None)) # Watch signals @nonblocking def _trap_sigwatch(sigset): # Initialize the signal handling part of the kernel if not done already # Note: This only works if running in the main thread if self._kernel_task_id is None: _init_loopback_task() if self._signal_sets is None: self._init_signals() self._signal_watch(sigset) # Unwatch signals @nonblocking def _trap_sigunwatch(sigset): self._signal_unwatch(sigset) # Wait for a signal @blocking def _trap_sigwait(sigset): sigset.waiting = current return ('SIGNAL_WAIT', lambda: setattr(sigset, 'waiting', None)) # Set a timeout to be delivered to the calling task @nonblocking def _trap_set_timeout(timeout): old_timeout = current.timeout if timeout is None: # If no timeout period is given, leave the current timeout in effect pass else: _set_timeout(timeout) if old_timeout and current.timeout > old_timeout: current.timeout = old_timeout return old_timeout # Clear a previously set timeout @nonblocking def _trap_unset_timeout(previous): # Here's an evil corner case. Suppose the previous timeout in effect # has already expired? If so, then we need to arrange for a timeout # to be generated. However, this has to happen on the *next* blocking # call, not on this trap. That's because the "unset" timeout feature # is usually done in the finalization stage of the previous timeout # handling. If we were to raise a TaskTimeout here, it would get mixed # up with the prior timeout handling and all manner of head-explosion # will occur. now = time_monotonic() if previous and previous >= 0 and previous < now: # Perhaps create a TaskTimeout pending exception here. _set_timeout(previous) else: current.timeout = previous # But there's one other evil corner case. It's possible that # a timeout could be reset while a TaskTimeout exception # is pending. If that happens, it means that the task has # left the timeout block. We should probably take away the # pending exception. if isinstance(current.cancel_pending, TaskTimeout): current.cancel_pending = None # Return the running kernel @nonblocking def _trap_get_kernel(): return self # Return the currently running task @nonblocking def _trap_get_current(): return current # Return the current value of the kernel clock @nonblocking def _trap_clock(): return time_monotonic() # Create the traps tables traps = [None] * len(Traps) for trap in Traps: traps[trap] = locals()[trap.name] # Initialize the loopback task (if not already initialized) if self._kernel_task_id is None: _init_loopback_task() # If there are tasks on the ready queue already, must cancel # any prior pending I/O before re-entering the kernel loop for task in self._ready: if task._last_io: _unregister_event(*task._last_io) task._last_io = None # Return values for the send() method main_value = None main_exc = None main_task = None # Some support for async-generators def _init_async_gen(agen): from . import meta if agen.ag_code not in _safe_async_generators: _safe_async_generators[agen.ag_code] = meta._is_safe_generator( agen.ag_code) if not _safe_async_generators[ agen.ag_code] and not agen in finalize._finalized: # Inspect the code of the generator to see if it might be safe raise RuntimeError( "Async generator with async finalization must be wrapped by\n" "async with finalize(agen) as agen:\n" " async for n in agen:\n" " ...\n" "See PEP 533 for further discussion.") if hasattr(sys, 'set_asyncgen_hooks'): sys.set_asyncgen_hooks(_init_async_gen) # ------------------------------------------------------------ # Main Kernel Loop # ------------------------------------------------------------ while True: # If no main task is known, we yield in order to receive it if njobs == 0: coro, poll_timeout = yield (main_value, main_exc) main_value = main_exc = None main_task = _new_task(coro) if coro else None # If a task was created and a timeout was given, we impose a deadline on the task if main_task and poll_timeout: current = main_task _set_timeout(poll_timeout + time_monotonic()) del coro # Wait for an I/O event (or timeout) if ready: timeout = 0 elif sleeping: timeout = sleeping[0][0] - time_monotonic() if poll_timeout is not None and timeout > poll_timeout: timeout = poll_timeout else: if njobs == 0: timeout = poll_timeout else: timeout = None try: events = selector_select(timeout) except OSError as e: # If there is nothing to select, windows throws an # OSError, so just set events to an empty list. log.error('Exception %r from selector_select ignored ' % e, exc_info=True) events = [] # Reschedule tasks with completed I/O for key, mask in events: rtask, wtask = key.data intfd = isinstance(key.fileobj, int) if mask & EVENT_READ: # Discussion: If the associated fileobj is # *not* a bare integer file descriptor, we # keep a record of the last I/O event in # _last_io and leave the task registered on # the event loop. If it performs the same I/O # operation again, it will get a speed boost # from not having to re-register its # event. However, it's not safe to use this # optimization with bare integer fds. These # fds often get reused and there is a # possibility that a fd will get closed and # reopened on a different resource without it # being detected by the kernel. For that case, # its critical that we not leave the fd on the # event loop. rtask._last_io = None if intfd else (key.fileobj, EVENT_READ) _reschedule_task(rtask) mask &= ~EVENT_READ rtask = None if mask & EVENT_WRITE: wtask._last_io = None if intfd else (key.fileobj, EVENT_WRITE) _reschedule_task(wtask) mask &= ~EVENT_WRITE wtask = None # Unregister the task if fileobj is not an integer fd (see # note above). if intfd: if mask: selector_modify(key.fileobj, mask, (rtask, wtask)) else: selector_unregister(key.fileobj) # Process sleeping tasks (if any) if sleeping: current_time = time_monotonic() while sleeping and sleeping[0][0] <= current_time: tm, taskid, sleep_type = heapq.heappop(sleeping) # When a task wakes, verify that the timeout value matches that stored # on the task. If it differs, it means that the task completed its # operation, was cancelled, or is no longer concerned with this # sleep operation. In that case, we do nothing if taskid in tasks: task = tasks[taskid] if sleep_type == 'sleep': if tm == task.sleep: task.sleep = None _reschedule_task(task, value=current_time) else: if tm == task.timeout: task.timeout = None # If cancellation is allowed and the task is blocked, reschedule it if task.allow_cancel and task.cancel_func: task.cancel_func() _reschedule_task( task, exc=TaskTimeout(current_time)) else: # Task is on the ready queue or can't be cancelled right now, # mark it as pending cancellation task.cancel_pending = TaskTimeout( current_time) # -------- # Run ready tasks # -------- # We only run the tasks that were already in the queue when we # started the loop. Any new tasks that are rescheduled onto the # ready queue while we're going will have to wait until the next # iteration of the outer loop, after we've checked for I/O and # sleepers. This avoids various potential pathologies that could # otherwise occur where tasks repeatedly reschedule themselves so # the queue never empties and we end up never checking for I/O. for _ in range(len(ready)): current = ready_popleft() try: if warn_if_task_blocks_for: task_start = time_monotonic() current.state = 'RUNNING' current.cycles += 1 with _enable_tasklocal_for(current): if current.next_exc is None: trap = current._send(current.next_value) current.next_value = None else: trap = current._throw(current.next_exc) current.next_exc = None # If the trap is nonblocking, then handle it # immediately without # rescheduling. Nonblocking trap handlers have # a different API than blocking trap handlers # -- they just return or raise whatever the # trap should return or raise. trapfunc = traps[trap[0]] while not trapfunc.blocking: try: next_value = trapfunc(*trap[1:]) except Exception as next_exc: trap = current._throw(next_exc) else: trap = current._send(next_value) trapfunc = traps[trap[0]] # Execute a blocking trap assert trapfunc.blocking # If there is a cancellation pending and delivery is allowed, # reschedule the task with the pending exception if current.allow_cancel and current.cancel_pending: _reschedule_task(current, exc=current.cancel_pending) current.cancel_pending = None else: current.state, current.cancel_func = trapfunc( *trap[1:]) except StopIteration as e: if current.cancel_pending: _cleanup_task(current, exc=current.cancel_pending) current.state = 'CANCELLED' else: _cleanup_task(current, value=e.value) current.state = 'TERMINATED' except (CancelledError, TaskExit) as e: current.exc_info = sys.exc_info() current.state = 'CANCELLED' _cleanup_task(current, exc=e) except Exception as e: current.exc_info = sys.exc_info() current.state = 'CRASHED' exc = TaskError('Task Crashed') exc.__cause__ = e _cleanup_task(current, exc=exc) if self._log_errors: log.error('Curio: Task Crash: %s' % current, exc_info=True) except: # (SystemExit, KeyboardInterrupt): _cleanup_task(current) current.state = 'TERMINATED' raise finally: if warn_if_task_blocks_for: duration = time_monotonic() - task_start if duration > warn_if_task_blocks_for: msg = ("Event loop blocked for {:0.1f} ms " "inside '{}' (task {})".format( 1000 * duration, current.coro.__qualname__, current.id)) warnings.warn(BlockingTaskWarning(msg)) # Unregister previous I/O request. Discussion follows: # # When a task performs I/O, it registers itself with the underlying # I/O selector. When the task is reawakened, it unregisters itself # and prepares to run. However, in many network applications, the # task will perform a small amount of work and then go to sleep on # exactly the same I/O resource that it was waiting on before. For # example, a client handling task in a server will often spend most # of its time waiting for incoming data on a single socket. # # Instead of always unregistering the task from the selector, we # can defer the unregistration process until after the task goes # back to sleep again. If it happens to be sleeping on the same # resource as before, there's no need to unregister it--it will # still be registered from the last I/O operation. # # The code here performs the unregister step for a task that # ran, but is now sleeping for a *different* reason than repeating the # prior I/O operation. There is coordination with code in _trap_io(). if current._last_io: _unregister_event(*current._last_io) current._last_io = None
def run(self, coro=None, *, shutdown=False, timeout=None): if coro and self._crashed: raise RuntimeError( "Can't submit further tasks to a crashed kernel.") if getattr(self._local, 'running', False): raise RuntimeError('Only one Curio kernel per thread is allowed') self._local.running = True if hasattr(sys, 'get_asyncgen_hooks'): asyncgen_hooks = sys.get_asyncgen_hooks() try: if not self._runner: self._runner = self._run_coro() self._runner.send(None) # Submit the given coroutine (if any) try: if coro or not shutdown: ret_val, ret_exc = self._runner.send((coro, timeout)) else: ret_val = ret_exc = None except BaseException as e: # If the underlying runner coroutine died for some reason, # then something bad happened. Maybe a KeyboardInterrupt # an internal programming program. We'll remove it and # mark the kernel as crashed. It's still possible that someone # will attempt a kernel shutdown later. self._runner = None self._crashed = True raise # If shutdown has been requested, run the shutdown process if shutdown: # For "reasons" related to task scheduling, the task # of shutting down all remaining tasks is best managed # by a launching a task dedicated to carrying out the task (sic) async def _shutdown_tasks(tocancel): for task in tocancel: try: await task.cancel() except Exception as e: log.error( 'Exception %r ignored in curio shutdown' % e, exc_info=True) while self._tasks: tocancel = [ task for task in self._tasks.values() if task.id != self._kernel_task_id ] tocancel.sort(key=lambda t: t.id) if self._kernel_task_id: tocancel.append(self._tasks[self._kernel_task_id]) for task in tocancel: task.daemon = True self._runner.send((_shutdown_tasks(tocancel), None)) self._kernel_task_id = None self._runner.close() del self._runner self._shutdown_resources() if ret_exc: raise ret_exc else: return ret_val finally: self._local.running = False if hasattr(sys, 'set_asyncgen_hooks'): sys.set_asyncgen_hooks(*asyncgen_hooks)
def install_hooks(self, runner): def firstiter(agen): if hasattr(_run.GLOBAL_RUN_CONTEXT, "task"): self.alive.add(agen) else: # An async generator first iterated outside of a Trio # task doesn't belong to Trio. Probably we're in guest # mode and the async generator belongs to our host. # The locals dictionary is the only good place to # remember this fact, at least until # https://bugs.python.org/issue40916 is implemented. agen.ag_frame.f_locals["@trio_foreign_asyncgen"] = True if self.prev_hooks.firstiter is not None: self.prev_hooks.firstiter(agen) def finalize_in_trio_context(agen, agen_name): try: runner.spawn_system_task( self._finalize_one, agen, agen_name, name=f"close asyncgen {agen_name} (abandoned)", ) except RuntimeError: # There is a one-tick window where the system nursery # is closed but the init task hasn't yet made # self.asyncgens a strong set to disable GC. We seem to # have hit it. self.trailing_needs_finalize.add(agen) def finalizer(agen): agen_name = name_asyncgen(agen) try: is_ours = not agen.ag_frame.f_locals.get( "@trio_foreign_asyncgen") except AttributeError: # pragma: no cover is_ours = True if is_ours: runner.entry_queue.run_sync_soon(finalize_in_trio_context, agen, agen_name) # Do this last, because it might raise an exception # depending on the user's warnings filter. (That # exception will be printed to the terminal and # ignored, since we're running in GC context.) warnings.warn( f"Async generator {agen_name!r} was garbage collected before it " f"had been exhausted. Surround its use in 'async with " f"aclosing(...):' to ensure that it gets cleaned up as soon as " f"you're done using it.", ResourceWarning, stacklevel=2, source=agen, ) else: # Not ours -> forward to the host loop's async generator finalizer if self.prev_hooks.finalizer is not None: self.prev_hooks.finalizer(agen) else: # Host has no finalizer. Reimplement the default # Python behavior with no hooks installed: throw in # GeneratorExit, step once, raise RuntimeError if # it doesn't exit. closer = agen.aclose() try: # If the next thing is a yield, this will raise RuntimeError # which we allow to propagate closer.send(None) except StopIteration: pass else: # If the next thing is an await, we get here. Give a nicer # error than the default "async generator ignored GeneratorExit" raise RuntimeError( f"Non-Trio async generator {agen_name!r} awaited something " f"during finalization; install a finalization hook to " f"support this, or wrap it in 'async with aclosing(...):'" ) self.prev_hooks = sys.get_asyncgen_hooks() sys.set_asyncgen_hooks(firstiter=firstiter, finalizer=finalizer)
def close(self): sys.set_asyncgen_hooks(*self.prev_hooks)
def _run_event_loop_once_cooperatively(self): """Compute the next moment at which the event loop should run delayed tasks, then ask Android to wake us up at that time. I/O waiting is handled separately (currently unimplemented). Since this is effectively the actual event loop, it also handles stopping the loop.""" # If we are supposed to stop, actually stop. if self._stopping: self._stopping = False self._thread_id = None asyncio.events._set_running_loop(None) self._set_coroutine_origin_tracking(False) sys.set_asyncgen_hooks(*self._old_agen_hooks) # Remove Android-specific object. self._handler = None # If we have actually already stopped, then do nothing. if self._thread_id is None: return # Based heavily on `BaseEventLoop._run_once()` from CPython. _MIN_SCHEDULED_TIMER_HANDLES = 100 _MIN_CANCELLED_TIMER_HANDLES_FRACTION = 0.5 MAXIMUM_SELECT_TIMEOUT = 24 * 3600 sched_count = len(self._scheduled) if (sched_count > _MIN_SCHEDULED_TIMER_HANDLES and self._timer_cancelled_count / sched_count > _MIN_CANCELLED_TIMER_HANDLES_FRACTION): # Remove delayed calls that were cancelled if their number # is too high new_scheduled = [] for handle in self._scheduled: if handle._cancelled: handle._scheduled = False else: new_scheduled.append(handle) heapq.heapify(new_scheduled) self._scheduled = new_scheduled self._timer_cancelled_count = 0 else: # Remove delayed calls that were cancelled from head of queue. while self._scheduled and self._scheduled[0]._cancelled: self._timer_cancelled_count -= 1 handle = heapq.heappop(self._scheduled) handle._scheduled = False timeout = None if self._ready or self._stopping: timeout = 0 elif self._scheduled: # Compute the desired timeout. when = self._scheduled[0]._when timeout = min(max(0, when - self.time()), MAXIMUM_SELECT_TIMEOUT) if timeout is None: # No delayed tasks, so we can return. The loop is running, ready for others to add tasks. return # TODO: When we implement FD-based wakeup, decide if the below causes excessive wakeups. self._android_call_later( self._runnables["_run_scheduled_callbacks_then_restart_loop"], timeout * 1000, )