45ef595fde
Instead of using the expiring cache type as a means to store worker information just avoid using that type since we don't support expiry in the first place on worker information and use a worker container and a worker object that we can later extend as needed. Also add on clear methods to the cache type that will be used when the WBE executor stop occurs. This ensures we clear out the worker information and any unfinished requests. Change-Id: I6a520376eff1e8a6edcef0a59f2d8b9c0eb15752
250 lines
11 KiB
Python
250 lines
11 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright (C) 2014 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import functools
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from oslo_utils import timeutils
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from taskflow.engines.action_engine import executor
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from taskflow.engines.worker_based import protocol as pr
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from taskflow.engines.worker_based import proxy
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from taskflow.engines.worker_based import types as wt
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from taskflow import exceptions as exc
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from taskflow import logging
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from taskflow import task as task_atom
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from taskflow.types import timing as tt
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from taskflow.utils import misc
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from taskflow.utils import threading_utils as tu
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LOG = logging.getLogger(__name__)
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class WorkerTaskExecutor(executor.TaskExecutor):
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"""Executes tasks on remote workers."""
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def __init__(self, uuid, exchange, topics,
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transition_timeout=pr.REQUEST_TIMEOUT,
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url=None, transport=None, transport_options=None,
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retry_options=None):
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self._uuid = uuid
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self._topics = topics
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self._requests_cache = wt.RequestsCache()
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self._workers = wt.TopicWorkers()
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self._transition_timeout = transition_timeout
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type_handlers = {
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pr.NOTIFY: [
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self._process_notify,
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functools.partial(pr.Notify.validate, response=True),
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],
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pr.RESPONSE: [
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self._process_response,
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pr.Response.validate,
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],
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}
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self._proxy = proxy.Proxy(uuid, exchange, type_handlers,
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on_wait=self._on_wait, url=url,
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transport=transport,
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transport_options=transport_options,
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retry_options=retry_options)
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self._proxy_thread = None
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self._periodic = wt.PeriodicWorker(tt.Timeout(pr.NOTIFY_PERIOD),
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[self._notify_topics])
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self._periodic_thread = None
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def _process_notify(self, notify, message):
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"""Process notify message from remote side."""
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LOG.debug("Started processing notify message '%s'",
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message.delivery_tag)
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topic = notify['topic']
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tasks = notify['tasks']
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# Add worker info to the cache
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worker = self._workers.add(topic, tasks)
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LOG.debug("Received notification about worker '%s' (%s"
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" total workers are currently known)", worker,
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len(self._workers))
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# Publish waiting requests
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for request in self._requests_cache.get_waiting_requests(worker):
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if request.transition_and_log_error(pr.PENDING, logger=LOG):
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self._publish_request(request, worker)
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def _process_response(self, response, message):
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"""Process response from remote side."""
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LOG.debug("Started processing response message '%s'",
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message.delivery_tag)
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try:
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task_uuid = message.properties['correlation_id']
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except KeyError:
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LOG.warning("The 'correlation_id' message property is missing")
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else:
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request = self._requests_cache.get(task_uuid)
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if request is not None:
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response = pr.Response.from_dict(response)
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LOG.debug("Response with state '%s' received for '%s'",
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response.state, request)
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if response.state == pr.RUNNING:
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request.transition_and_log_error(pr.RUNNING, logger=LOG)
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elif response.state == pr.EVENT:
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# Proxy the event + details to the task/request notifier...
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event_type = response.data['event_type']
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details = response.data['details']
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request.notifier.notify(event_type, details)
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elif response.state in (pr.FAILURE, pr.SUCCESS):
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moved = request.transition_and_log_error(response.state,
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logger=LOG)
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if moved:
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# NOTE(imelnikov): request should not be in the
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# cache when another thread can see its result and
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# schedule another request with the same uuid; so
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# we remove it, then set the result...
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del self._requests_cache[request.uuid]
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request.set_result(**response.data)
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else:
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LOG.warning("Unexpected response status '%s'",
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response.state)
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else:
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LOG.debug("Request with id='%s' not found", task_uuid)
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@staticmethod
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def _handle_expired_request(request):
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"""Handle expired request.
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When request has expired it is removed from the requests cache and
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the `RequestTimeout` exception is set as a request result.
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"""
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if request.transition_and_log_error(pr.FAILURE, logger=LOG):
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# Raise an exception (and then catch it) so we get a nice
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# traceback that the request will get instead of it getting
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# just an exception with no traceback...
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try:
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request_age = timeutils.delta_seconds(request.created_on,
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timeutils.utcnow())
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raise exc.RequestTimeout(
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"Request '%s' has expired after waiting for %0.2f"
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" seconds for it to transition out of (%s) states"
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% (request, request_age, ", ".join(pr.WAITING_STATES)))
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except exc.RequestTimeout:
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with misc.capture_failure() as failure:
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LOG.debug(failure.exception_str)
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request.set_result(failure)
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def _on_wait(self):
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"""This function is called cyclically between draining events."""
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self._requests_cache.cleanup(self._handle_expired_request)
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def _submit_task(self, task, task_uuid, action, arguments,
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progress_callback=None, **kwargs):
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"""Submit task request to a worker."""
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request = pr.Request(task, task_uuid, action, arguments,
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self._transition_timeout, **kwargs)
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# Register the callback, so that we can proxy the progress correctly.
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if (progress_callback is not None and
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request.notifier.can_be_registered(
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task_atom.EVENT_UPDATE_PROGRESS)):
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request.notifier.register(task_atom.EVENT_UPDATE_PROGRESS,
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progress_callback)
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cleaner = functools.partial(request.notifier.deregister,
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task_atom.EVENT_UPDATE_PROGRESS,
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progress_callback)
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request.result.add_done_callback(lambda fut: cleaner())
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# Get task's worker and publish request if worker was found.
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worker = self._workers.get_worker_for_task(task)
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if worker is not None:
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# NOTE(skudriashev): Make sure request is set to the PENDING state
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# before putting it into the requests cache to prevent the notify
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# processing thread get list of waiting requests and publish it
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# before it is published here, so it wouldn't be published twice.
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if request.transition_and_log_error(pr.PENDING, logger=LOG):
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self._requests_cache[request.uuid] = request
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self._publish_request(request, worker)
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else:
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LOG.debug("Delaying submission of '%s', no currently known"
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" worker/s available to process it", request)
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self._requests_cache[request.uuid] = request
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return request.result
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def _publish_request(self, request, worker):
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"""Publish request to a given topic."""
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LOG.debug("Submitting execution of '%s' to worker '%s' (expecting"
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" response identified by reply_to=%s and"
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" correlation_id=%s)", request, worker, self._uuid,
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request.uuid)
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try:
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self._proxy.publish(request, worker.topic,
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reply_to=self._uuid,
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correlation_id=request.uuid)
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except Exception:
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with misc.capture_failure() as failure:
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LOG.critical("Failed to submit '%s' (transitioning it to"
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" %s)", request, pr.FAILURE, exc_info=True)
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if request.transition_and_log_error(pr.FAILURE, logger=LOG):
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del self._requests_cache[request.uuid]
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request.set_result(failure)
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def _notify_topics(self):
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"""Cyclically called to publish notify message to each topic."""
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self._proxy.publish(pr.Notify(), self._topics, reply_to=self._uuid)
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def execute_task(self, task, task_uuid, arguments,
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progress_callback=None):
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return self._submit_task(task, task_uuid, pr.EXECUTE, arguments,
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progress_callback=progress_callback)
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def revert_task(self, task, task_uuid, arguments, result, failures,
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progress_callback=None):
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return self._submit_task(task, task_uuid, pr.REVERT, arguments,
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progress_callback=progress_callback,
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result=result, failures=failures)
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def wait_for_workers(self, workers=1, timeout=None):
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"""Waits for geq workers to notify they are ready to do work.
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NOTE(harlowja): if a timeout is provided this function will wait
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until that timeout expires, if the amount of workers does not reach
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the desired amount of workers before the timeout expires then this will
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return how many workers are still needed, otherwise it will
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return zero.
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"""
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return self._workers.wait_for_workers(workers=workers, timeout=timeout)
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def start(self):
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"""Starts proxy thread and associated topic notification thread."""
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if not tu.is_alive(self._proxy_thread):
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self._proxy_thread = tu.daemon_thread(self._proxy.start)
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self._proxy_thread.start()
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self._proxy.wait()
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if not tu.is_alive(self._periodic_thread):
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self._periodic.reset()
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self._periodic_thread = tu.daemon_thread(self._periodic.start)
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self._periodic_thread.start()
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def stop(self):
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"""Stops proxy thread and associated topic notification thread."""
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if self._periodic_thread is not None:
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self._periodic.stop()
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self._periodic_thread.join()
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self._periodic_thread = None
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if self._proxy_thread is not None:
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self._proxy.stop()
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self._proxy_thread.join()
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self._proxy_thread = None
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self._requests_cache.clear(self._handle_expired_request)
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self._workers.clear()
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