8e8fd65225
First try to get them, but if they aren't able to be serialized, just return the failure without them. This only affects the WBE that serializes failures as part of the JSON response that is sent over the wire from the worker process to the WBE engine. Change-Id: I86e3255b612bc15097aabe63a684cf8b8808e61b
262 lines
11 KiB
Python
262 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 reflection
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from oslo_utils import timeutils
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from taskflow.engines.worker_based import dispatcher
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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 logging
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from taskflow.types import failure as ft
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from taskflow.types import notifier as nt
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from taskflow.utils import kombu_utils as ku
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from taskflow.utils import misc
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LOG = logging.getLogger(__name__)
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class Server(object):
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"""Server implementation that waits for incoming tasks requests."""
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def __init__(self, topic, exchange, executor, endpoints,
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url=None, transport=None, transport_options=None,
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retry_options=None):
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type_handlers = {
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pr.NOTIFY: dispatcher.Handler(
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self._delayed_process(self._process_notify),
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validator=functools.partial(pr.Notify.validate,
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response=False)),
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pr.REQUEST: dispatcher.Handler(
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self._delayed_process(self._process_request),
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validator=pr.Request.validate),
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}
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self._executor = executor
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self._proxy = proxy.Proxy(topic, exchange,
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type_handlers=type_handlers,
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url=url, transport=transport,
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transport_options=transport_options,
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retry_options=retry_options)
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self._topic = topic
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self._endpoints = dict([(endpoint.name, endpoint)
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for endpoint in endpoints])
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def _delayed_process(self, func):
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"""Runs the function using the instances executor (eventually).
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This adds a *nice* benefit on showing how long it took for the
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function to finally be executed from when the message was received
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to when it was finally ran (which can be a nice thing to know
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to determine bottle-necks...).
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"""
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func_name = reflection.get_callable_name(func)
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def _on_run(watch, content, message):
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LOG.trace("It took %s seconds to get around to running"
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" function/method '%s' with"
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" message '%s'", watch.elapsed(), func_name,
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ku.DelayedPretty(message))
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return func(content, message)
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def _on_receive(content, message):
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LOG.debug("Submitting message '%s' for execution in the"
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" future to '%s'", ku.DelayedPretty(message), func_name)
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watch = timeutils.StopWatch()
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watch.start()
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try:
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self._executor.submit(_on_run, watch, content, message)
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except RuntimeError:
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LOG.error("Unable to continue processing message '%s',"
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" submission to instance executor (with later"
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" execution by '%s') was unsuccessful",
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ku.DelayedPretty(message), func_name,
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exc_info=True)
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return _on_receive
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@property
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def connection_details(self):
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return self._proxy.connection_details
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@staticmethod
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def _parse_message(message):
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"""Extracts required attributes out of the messages properties.
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This extracts the `reply_to` and the `correlation_id` properties. If
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any of these required properties are missing a `ValueError` is raised.
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"""
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properties = []
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for prop in ('reply_to', 'correlation_id'):
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try:
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properties.append(message.properties[prop])
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except KeyError:
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raise ValueError("The '%s' message property is missing" %
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prop)
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return properties
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def _reply(self, capture, reply_to, task_uuid, state=pr.FAILURE, **kwargs):
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"""Send a reply to the `reply_to` queue with the given information.
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Can capture failures to publish and if capturing will log associated
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critical errors on behalf of the caller, and then returns whether the
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publish worked out or did not.
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"""
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response = pr.Response(state, **kwargs)
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published = False
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try:
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self._proxy.publish(response, reply_to, correlation_id=task_uuid)
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published = True
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except Exception:
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if not capture:
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raise
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LOG.critical("Failed to send reply to '%s' for task '%s' with"
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" response %s", reply_to, task_uuid, response,
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exc_info=True)
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return published
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def _on_event(self, reply_to, task_uuid, event_type, details):
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"""Send out a task event notification."""
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# NOTE(harlowja): the executor that will trigger this using the
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# task notification/listener mechanism will handle logging if this
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# fails, so thats why capture is 'False' is used here.
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self._reply(False, reply_to, task_uuid, pr.EVENT,
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event_type=event_type, details=details)
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def _process_notify(self, notify, message):
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"""Process notify message and reply back."""
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try:
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reply_to = message.properties['reply_to']
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except KeyError:
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LOG.warn("The 'reply_to' message property is missing"
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" in received notify message '%s'",
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ku.DelayedPretty(message), exc_info=True)
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else:
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response = pr.Notify(topic=self._topic,
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tasks=self._endpoints.keys())
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try:
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self._proxy.publish(response, routing_key=reply_to)
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except Exception:
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LOG.critical("Failed to send reply to '%s' with notify"
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" response '%s'", reply_to, response,
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exc_info=True)
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def _process_request(self, request, message):
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"""Process request message and reply back."""
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try:
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# NOTE(skudriashev): parse broker message first to get
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# the `reply_to` and the `task_uuid` parameters to have
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# possibility to reply back (if we can't parse, we can't respond
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# in the first place...).
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reply_to, task_uuid = self._parse_message(message)
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except ValueError:
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LOG.warn("Failed to parse request attributes from message '%s'",
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ku.DelayedPretty(message), exc_info=True)
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return
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else:
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# prepare reply callback
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reply_callback = functools.partial(self._reply, True, reply_to,
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task_uuid)
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# Parse the request to get the activity/work to perform.
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try:
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work = pr.Request.from_dict(request, task_uuid=task_uuid)
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except ValueError:
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with misc.capture_failure() as failure:
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LOG.warn("Failed to parse request contents from message '%s'",
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ku.DelayedPretty(message), exc_info=True)
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reply_callback(result=pr.failure_to_dict(failure))
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return
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# Now fetch the task endpoint (and action handler on it).
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try:
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endpoint = self._endpoints[work.task_cls]
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except KeyError:
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with misc.capture_failure() as failure:
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LOG.warn("The '%s' task endpoint does not exist, unable"
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" to continue processing request message '%s'",
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work.task_cls, ku.DelayedPretty(message),
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exc_info=True)
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reply_callback(result=pr.failure_to_dict(failure))
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return
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else:
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try:
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handler = getattr(endpoint, work.action)
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except AttributeError:
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with misc.capture_failure() as failure:
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LOG.warn("The '%s' handler does not exist on task endpoint"
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" '%s', unable to continue processing request"
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" message '%s'", work.action, endpoint,
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ku.DelayedPretty(message), exc_info=True)
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reply_callback(result=pr.failure_to_dict(failure))
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return
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else:
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try:
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task = endpoint.generate(name=work.task_name)
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except Exception:
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with misc.capture_failure() as failure:
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LOG.warn("The '%s' task '%s' generation for request"
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" message '%s' failed", endpoint, work.action,
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ku.DelayedPretty(message), exc_info=True)
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reply_callback(result=pr.failure_to_dict(failure))
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return
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else:
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if not reply_callback(state=pr.RUNNING):
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return
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# Associate *any* events this task emits with a proxy that will
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# emit them back to the engine... for handling at the engine side
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# of things...
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if task.notifier.can_be_registered(nt.Notifier.ANY):
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task.notifier.register(nt.Notifier.ANY,
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functools.partial(self._on_event,
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reply_to, task_uuid))
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elif isinstance(task.notifier, nt.RestrictedNotifier):
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# Only proxy the allowable events then...
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for event_type in task.notifier.events_iter():
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task.notifier.register(event_type,
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functools.partial(self._on_event,
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reply_to, task_uuid))
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# Perform the task action.
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try:
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result = handler(task, **work.arguments)
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except Exception:
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with misc.capture_failure() as failure:
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LOG.warn("The '%s' endpoint '%s' execution for request"
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" message '%s' failed", endpoint, work.action,
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ku.DelayedPretty(message), exc_info=True)
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reply_callback(result=pr.failure_to_dict(failure))
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else:
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# And be done with it!
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if isinstance(result, ft.Failure):
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reply_callback(result=result.to_dict())
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else:
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reply_callback(state=pr.SUCCESS, result=result)
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def start(self):
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"""Start processing incoming requests."""
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self._proxy.start()
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def wait(self):
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"""Wait until server is started."""
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self._proxy.wait()
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def stop(self):
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"""Stop processing incoming requests."""
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self._proxy.stop()
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