14431bc076
Add a new logging BLATHER level to easily allow its usage for messages that are below the normal DEBUG level such as compilation information and scope lookup info which can be very verbose in logs if always enabled. Change-Id: I828211403bd02bfd6777b10cdcfe58fb0637a52c
238 lines
9.3 KiB
Python
238 lines
9.3 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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import six
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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.utils import misc
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LOG = logging.getLogger(__name__)
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def delayed(executor):
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"""Wraps & runs the function using a futures compatible executor."""
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def decorator(f):
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@six.wraps(f)
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def wrapper(*args, **kwargs):
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return executor.submit(f, *args, **kwargs)
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return wrapper
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return decorator
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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, **kwargs):
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handlers = {
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pr.NOTIFY: [
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delayed(executor)(self._process_notify),
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functools.partial(pr.Notify.validate, response=False),
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],
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pr.REQUEST: [
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delayed(executor)(self._process_request),
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pr.Request.validate,
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],
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}
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self._proxy = proxy.Proxy(topic, exchange, handlers,
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on_wait=None, **kwargs)
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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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@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_request(task_cls, task_name, action, arguments, result=None,
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failures=None, **kwargs):
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"""Parse request before it can be further processed.
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All `failure.Failure` objects that have been converted to dict on the
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remote side will now converted back to `failure.Failure` objects.
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"""
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action_args = dict(arguments=arguments, task_name=task_name)
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if result is not None:
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data_type, data = result
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if data_type == 'failure':
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action_args['result'] = ft.Failure.from_dict(data)
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else:
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action_args['result'] = data
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if failures is not None:
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action_args['failures'] = {}
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for key, data in six.iteritems(failures):
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action_args['failures'][key] = ft.Failure.from_dict(data)
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return task_cls, action, action_args
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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_update_progress(self, reply_to, task_uuid, task, event_data,
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progress):
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"""Send task update progress 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.PROGRESS,
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event_data=event_data, progress=progress)
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def _process_notify(self, notify, message):
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"""Process notify message and reply back."""
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LOG.debug("Started processing notify message %r", message.delivery_tag)
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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 %r", message.delivery_tag,
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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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LOG.debug("Started processing request message %r",
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message.delivery_tag)
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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 %r",
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message.delivery_tag, exc_info=True)
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return
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else:
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# prepare task progress callback
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progress_callback = functools.partial(self._on_update_progress,
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reply_to, task_uuid)
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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 request to get task name, action and action arguments
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try:
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task_cls, action, action_args = self._parse_request(**request)
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action_args.update(task_uuid=task_uuid,
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progress_callback=progress_callback)
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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 %r",
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message.delivery_tag, exc_info=True)
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reply_callback(result=failure.to_dict())
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return
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# get task endpoint
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try:
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endpoint = self._endpoints[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 %r",
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task_cls, message.delivery_tag, exc_info=True)
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reply_callback(result=failure.to_dict())
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return
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else:
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try:
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handler = getattr(endpoint, 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 %r", action, endpoint,
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message.delivery_tag, exc_info=True)
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reply_callback(result=failure.to_dict())
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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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# perform task action
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try:
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result = handler(**action_args)
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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 %r failed", endpoint, action,
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message.delivery_tag, exc_info=True)
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reply_callback(result=failure.to_dict())
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else:
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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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