def __exit__(self, exc_type, exc_value, traceback):
self._context_guard = False
# Exiting due to exception, return to allow exception to bubble
if exc_type or exc_value or traceback:
return
if not self.is_complete:
pending_action = (self._executable + self._pending_abandon +
self._pending_retry + self._pending_skip)
state_str = "{pending_str}{in_flight_str}{action_str}{retry_str}".format(
in_flight_str="\nSteps still in flight: {}".format(
self._in_flight) if self._in_flight else "",
pending_str="\nSteps pending processing: {}".format(
self._pending.keys()) if self._pending else "",
action_str="\nSteps pending action: {}".format(pending_action)
if pending_action else "",
retry_str="\nSteps waiting to retry: {}".format(
self._waiting_to_retry.keys())
if self._waiting_to_retry else "",
)
if self._interrupted:
raise DagsterExecutionInterruptedError(
f"Execution of pipeline was interrupted before completing the execution plan. {state_str}"
)
else:
raise DagsterInvariantViolationError(
f"Execution of pipeline finished without completing the execution plan. {state_str}"
)
# See verify_complete - steps for which we did not observe a failure/success event are in an unknown
# state so we raise to ensure pipeline failure.
if len(self._unknown_state) > 0:
if self._interrupted:
raise DagsterExecutionInterruptedError(
"Execution of pipeline exited with steps {step_list} in an unknown state after "
"being interrupted.".format(step_list=self._unknown_state))
else:
raise DagsterUnknownStepStateError(
"Execution of pipeline exited with steps {step_list} in an unknown state to this process.\n"
"This was likely caused by losing communication with the process performing step execution."
.format(step_list=self._unknown_state))
def execute(self, pipeline_context, execution_plan):
check.inst_param(pipeline_context, "pipeline_context",
SystemPipelineExecutionContext)
check.inst_param(execution_plan, "execution_plan", ExecutionPlan)
limit = self.max_concurrent
yield DagsterEvent.engine_event(
pipeline_context,
"Executing steps using multiprocess executor: parent process (pid: {pid})"
.format(pid=os.getpid()),
event_specific_data=EngineEventData.multiprocess(
os.getpid(),
step_keys_to_execute=execution_plan.step_keys_to_execute),
)
# It would be good to implement a reference tracking algorithm here so we could
# garbage collect results that are no longer needed by any steps
# https://github.com/dagster-io/dagster/issues/811
with time_execution_scope() as timer_result:
with execution_plan.start(
retry_mode=self.retries) as active_execution:
active_iters = {}
errors = {}
term_events = {}
stopping = False
while (not stopping
and not active_execution.is_complete) or active_iters:
if active_execution.check_for_interrupts():
yield DagsterEvent.engine_event(
pipeline_context,
"Multiprocess executor: received termination signal - "
"forwarding to active child processes",
EngineEventData.interrupted(
list(term_events.keys())),
)
stopping = True
active_execution.mark_interrupted()
for key, event in term_events.items():
event.set()
# start iterators
while len(active_iters) < limit and not stopping:
steps = active_execution.get_steps_to_execute(
limit=(limit - len(active_iters)))
if not steps:
break
for step in steps:
step_context = pipeline_context.for_step(step)
term_events[step.key] = multiprocessing.Event()
active_iters[
step.key] = self.execute_step_out_of_process(
step_context,
step,
errors,
term_events,
active_execution.get_known_state(),
)
# process active iterators
empty_iters = []
for key, step_iter in active_iters.items():
try:
event_or_none = next(step_iter)
if event_or_none is None:
continue
else:
yield event_or_none
active_execution.handle_event(event_or_none)
except ChildProcessCrashException as crash:
serializable_error = serializable_error_info_from_exc_info(
sys.exc_info())
yield DagsterEvent.engine_event(
pipeline_context,
("Multiprocess executor: child process for step {step_key} "
"unexpectedly exited with code {exit_code}"
).format(step_key=key,
exit_code=crash.exit_code),
EngineEventData.engine_error(
serializable_error),
step_handle=active_execution.get_step_by_key(
key).handle,
)
step_failure_event = DagsterEvent.step_failure_event(
step_context=pipeline_context.for_step(
active_execution.get_step_by_key(key)),
step_failure_data=StepFailureData(
error=serializable_error,
user_failure_data=None),
)
active_execution.handle_event(step_failure_event)
yield step_failure_event
empty_iters.append(key)
except StopIteration:
empty_iters.append(key)
# clear and mark complete finished iterators
for key in empty_iters:
del active_iters[key]
del term_events[key]
active_execution.verify_complete(pipeline_context, key)
# process skipped and abandoned steps
yield from active_execution.plan_events_iterator(
pipeline_context)
errs = {pid: err for pid, err in errors.items() if err}
# After termination starts, raise an interrupted exception once all subprocesses
# have finished cleaning up (and the only errors were from being interrupted)
if (stopping and (not active_iters) and all([
err_info.cls_name == "DagsterExecutionInterruptedError"
for err_info in errs.values()
])):
yield DagsterEvent.engine_event(
pipeline_context,
"Multiprocess executor: interrupted all active child processes",
event_specific_data=EngineEventData(),
)
raise DagsterExecutionInterruptedError()
elif errs:
raise DagsterSubprocessError(
"During multiprocess execution errors occurred in child processes:\n{error_list}"
.format(error_list="\n".join([
"In process {pid}: {err}".format(
pid=pid, err=err.to_string())
for pid, err in errs.items()
])),
subprocess_error_infos=list(errs.values()),
)
yield DagsterEvent.engine_event(
pipeline_context,
"Multiprocess executor: parent process exiting after {duration} (pid: {pid})"
.format(duration=format_duration(timer_result.millis),
pid=os.getpid()),
event_specific_data=EngineEventData.multiprocess(os.getpid()),
)