e9262893f3
Add and use this object to make it so that the worker executor notifier can run and also be interrupted when its owning thread is finished (thus allowing it to be finished before the timeout is reached). Change-Id: Ice9f3b74b894dd7a76ab94ba4561b9405eba0206
208 lines
8.4 KiB
Python
208 lines
8.4 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 logging
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import threading
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from kombu import exceptions as kombu_exc
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from taskflow.engines.action_engine import executor
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from taskflow.engines.worker_based import cache
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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 import exceptions as exc
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from taskflow.utils import async_utils
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from taskflow.utils import misc
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LOG = logging.getLogger(__name__)
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class WorkerTaskExecutor(executor.TaskExecutorBase):
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"""Executes tasks on remote workers."""
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def __init__(self, uuid, exchange, topics, **kwargs):
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self._uuid = uuid
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self._topics = topics
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self._requests_cache = cache.RequestsCache()
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self._workers_cache = cache.WorkersCache()
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self._proxy = proxy.Proxy(uuid, exchange, self._on_message,
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self._on_wait, **kwargs)
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self._proxy_thread = None
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self._notify_thread = None
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self._notify_timeout = misc.Timeout(pr.NOTIFY_PERIOD)
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def _make_thread(self, target):
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thread = threading.Thread(target=target)
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# NOTE(skudriashev): When the main thread is terminated unexpectedly
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# and thread is still alive - it will prevent main thread from exiting
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# unless the daemon property is set to True.
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thread.daemon = True
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return thread
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def _on_message(self, data, message):
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"""This method is called on incoming message."""
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LOG.debug("Got message: %s", data)
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try:
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# acknowledge message before processing
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message.ack()
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except kombu_exc.MessageStateError:
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LOG.exception("Failed to acknowledge AMQP message.")
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else:
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LOG.debug("AMQP message acknowledged.")
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try:
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msg_type = message.properties['type']
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except KeyError:
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LOG.warning("The 'type' message property is missing.")
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else:
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if msg_type == pr.NOTIFY:
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self._process_notify(data)
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elif msg_type == pr.RESPONSE:
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self._process_response(data, message)
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else:
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LOG.warning("Unexpected message type: %s", msg_type)
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def _process_notify(self, notify):
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"""Process notify message from remote side."""
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LOG.debug("Start processing notify message.")
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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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self._workers_cache.set(topic, tasks)
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# publish waiting requests
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for request in self._requests_cache.get_waiting_requests(tasks):
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request.set_pending()
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self._publish_request(request, topic)
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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("Start processing response message.")
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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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LOG.debug("Task uuid: '%s'", task_uuid)
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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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if response.state == pr.RUNNING:
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request.set_running()
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elif response.state == pr.PROGRESS:
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request.on_progress(**response.data)
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elif response.state in (pr.FAILURE, pr.SUCCESS):
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request.set_result(**response.data)
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self._requests_cache.delete(request.uuid)
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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 `Timeout` exception is set as a request result.
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"""
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LOG.debug("Request '%r' has expired.", request)
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LOG.debug("The '%r' request has expired.", request)
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request.set_result(misc.Failure.from_exception(
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exc.Timeout("The '%r' request has expired" % request)))
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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, timeout=pr.REQUEST_TIMEOUT, **kwargs):
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"""Submit task request to workers."""
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request = pr.Request(task, task_uuid, action, arguments,
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progress_callback, timeout, **kwargs)
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# Get task's topic and publish request if topic was found.
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topic = self._workers_cache.get_topic_by_task(request.task_cls)
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if topic 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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request.set_pending()
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self._requests_cache.set(request.uuid, request)
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self._publish_request(request, topic)
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else:
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self._requests_cache.set(request.uuid, request)
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return request.result
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def _publish_request(self, request, topic):
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"""Publish request to a given topic."""
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try:
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self._proxy.publish(msg=request,
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routing_key=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.exception("Failed to submit the '%s' request." %
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request)
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self._requests_cache.delete(request.uuid)
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request.set_result(failure)
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def _notify_topics(self):
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"""Cyclically publish notify message to each topic."""
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LOG.debug("Notify thread started.")
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while not self._notify_timeout.is_stopped():
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self._proxy.publish(pr.Notify(), self._topics, reply_to=self._uuid)
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self._notify_timeout.wait()
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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)
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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, result=result,
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failures=failures)
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def wait_for_any(self, fs, timeout=None):
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"""Wait for futures returned by this executor to complete."""
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return async_utils.wait_for_any(fs, timeout)
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def start(self):
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"""Start proxy thread."""
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if self._proxy_thread is None:
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self._proxy_thread = self._make_thread(self._proxy.start)
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self._proxy_thread.start()
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self._proxy.wait()
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self._notify_thread = self._make_thread(self._notify_topics)
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self._notify_thread.start()
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def stop(self):
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"""Stop proxy, so its thread would be gracefully terminated."""
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if self._proxy_thread is not None:
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if self._proxy_thread.is_alive():
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self._notify_timeout.interrupt()
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self._notify_thread.join()
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self._proxy.stop()
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self._proxy_thread.join()
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self._notify_thread = None
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self._proxy_thread = None
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