Files
deb-python-taskflow/taskflow/engines/worker_based/server.py
Joshua Harlow f836433063 Remove delayed decorator and replace with nicer method
Instead of having a delayed decorator that is in the module
have one that is attached onto the instance and that can log
how long it took for the target method to finally be ran.

Change-Id: Ie6e51b0a2a60a063554dfba7fcc321ecd6661949
2015-02-13 21:46:13 -08:00

289 lines
12 KiB
Python

# -*- coding: utf-8 -*-
# Copyright (C) 2014 Yahoo! Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import functools
from oslo_utils import reflection
import six
from taskflow.engines.worker_based import protocol as pr
from taskflow.engines.worker_based import proxy
from taskflow import logging
from taskflow.types import failure as ft
from taskflow.types import notifier as nt
from taskflow.types import timing as tt
from taskflow.utils import kombu_utils as ku
from taskflow.utils import misc
LOG = logging.getLogger(__name__)
class Server(object):
"""Server implementation that waits for incoming tasks requests."""
def __init__(self, topic, exchange, executor, endpoints,
url=None, transport=None, transport_options=None,
retry_options=None):
type_handlers = {
pr.NOTIFY: [
self._delayed_process(self._process_notify),
functools.partial(pr.Notify.validate, response=False),
],
pr.REQUEST: [
self._delayed_process(self._process_request),
pr.Request.validate,
],
}
self._executor = executor
self._proxy = proxy.Proxy(topic, exchange,
type_handlers=type_handlers,
url=url, transport=transport,
transport_options=transport_options,
retry_options=retry_options)
self._topic = topic
self._endpoints = dict([(endpoint.name, endpoint)
for endpoint in endpoints])
def _delayed_process(self, func):
"""Runs the function using the instances executor (eventually).
This adds a *nice* benefit on showing how long it took for the
function to finally be executed from when the message was received
to when it was finally ran (which can be a nice thing to know
to determine bottle-necks...).
"""
func_name = reflection.get_callable_name(func)
def _on_run(watch, content, message):
LOG.blather("It took %s seconds to get around to running"
" function/method '%s' with"
" message '%s'", watch.elapsed(), func_name,
ku.DelayedPretty(message))
return func(content, message)
def _on_receive(content, message):
LOG.debug("Submitting message '%s' for execution in the"
" future to '%s'", ku.DelayedPretty(message), func_name)
watch = tt.StopWatch()
watch.start()
try:
self._executor.submit(_on_run, watch, content, message)
except RuntimeError:
LOG.error("Unable to continue processing message '%s',"
" submission to instance executor (with later"
" execution by '%s') was unsuccessful",
ku.DelayedPretty(message), func_name,
exc_info=True)
return _on_receive
@property
def connection_details(self):
return self._proxy.connection_details
@staticmethod
def _parse_request(task_cls, task_name, action, arguments, result=None,
failures=None, **kwargs):
"""Parse request before it can be further processed.
All `failure.Failure` objects that have been converted to dict on the
remote side will now converted back to `failure.Failure` objects.
"""
# These arguments will eventually be given to the task executor
# so they need to be in a format it will accept (and using keyword
# argument names that it accepts)...
arguments = {
'arguments': arguments,
}
if result is not None:
data_type, data = result
if data_type == 'failure':
arguments['result'] = ft.Failure.from_dict(data)
else:
arguments['result'] = data
if failures is not None:
arguments['failures'] = {}
for key, data in six.iteritems(failures):
arguments['failures'][key] = ft.Failure.from_dict(data)
return (task_cls, task_name, action, arguments)
@staticmethod
def _parse_message(message):
"""Extracts required attributes out of the messages properties.
This extracts the `reply_to` and the `correlation_id` properties. If
any of these required properties are missing a `ValueError` is raised.
"""
properties = []
for prop in ('reply_to', 'correlation_id'):
try:
properties.append(message.properties[prop])
except KeyError:
raise ValueError("The '%s' message property is missing" %
prop)
return properties
def _reply(self, capture, reply_to, task_uuid, state=pr.FAILURE, **kwargs):
"""Send a reply to the `reply_to` queue with the given information.
Can capture failures to publish and if capturing will log associated
critical errors on behalf of the caller, and then returns whether the
publish worked out or did not.
"""
response = pr.Response(state, **kwargs)
published = False
try:
self._proxy.publish(response, reply_to, correlation_id=task_uuid)
published = True
except Exception:
if not capture:
raise
LOG.critical("Failed to send reply to '%s' for task '%s' with"
" response %s", reply_to, task_uuid, response,
exc_info=True)
return published
def _on_event(self, reply_to, task_uuid, event_type, details):
"""Send out a task event notification."""
# NOTE(harlowja): the executor that will trigger this using the
# task notification/listener mechanism will handle logging if this
# fails, so thats why capture is 'False' is used here.
self._reply(False, reply_to, task_uuid, pr.EVENT,
event_type=event_type, details=details)
def _process_notify(self, notify, message):
"""Process notify message and reply back."""
try:
reply_to = message.properties['reply_to']
except KeyError:
LOG.warn("The 'reply_to' message property is missing"
" in received notify message '%s'",
ku.DelayedPretty(message), exc_info=True)
else:
response = pr.Notify(topic=self._topic,
tasks=self._endpoints.keys())
try:
self._proxy.publish(response, routing_key=reply_to)
except Exception:
LOG.critical("Failed to send reply to '%s' with notify"
" response '%s'", reply_to, response,
exc_info=True)
def _process_request(self, request, message):
"""Process request message and reply back."""
try:
# NOTE(skudriashev): parse broker message first to get
# the `reply_to` and the `task_uuid` parameters to have
# possibility to reply back (if we can't parse, we can't respond
# in the first place...).
reply_to, task_uuid = self._parse_message(message)
except ValueError:
LOG.warn("Failed to parse request attributes from message '%s'",
ku.DelayedPretty(message), exc_info=True)
return
else:
# prepare reply callback
reply_callback = functools.partial(self._reply, True, reply_to,
task_uuid)
# parse request to get task name, action and action arguments
try:
bundle = self._parse_request(**request)
task_cls, task_name, action, arguments = bundle
arguments['task_uuid'] = task_uuid
except ValueError:
with misc.capture_failure() as failure:
LOG.warn("Failed to parse request contents from message '%s'",
ku.DelayedPretty(message), exc_info=True)
reply_callback(result=failure.to_dict())
return
# get task endpoint
try:
endpoint = self._endpoints[task_cls]
except KeyError:
with misc.capture_failure() as failure:
LOG.warn("The '%s' task endpoint does not exist, unable"
" to continue processing request message '%s'",
task_cls, ku.DelayedPretty(message), exc_info=True)
reply_callback(result=failure.to_dict())
return
else:
try:
handler = getattr(endpoint, action)
except AttributeError:
with misc.capture_failure() as failure:
LOG.warn("The '%s' handler does not exist on task endpoint"
" '%s', unable to continue processing request"
" message '%s'", action, endpoint,
ku.DelayedPretty(message), exc_info=True)
reply_callback(result=failure.to_dict())
return
else:
try:
task = endpoint.generate(name=task_name)
except Exception:
with misc.capture_failure() as failure:
LOG.warn("The '%s' task '%s' generation for request"
" message '%s' failed", endpoint, action,
ku.DelayedPretty(message), exc_info=True)
reply_callback(result=failure.to_dict())
return
else:
if not reply_callback(state=pr.RUNNING):
return
# associate *any* events this task emits with a proxy that will
# emit them back to the engine... for handling at the engine side
# of things...
if task.notifier.can_be_registered(nt.Notifier.ANY):
task.notifier.register(nt.Notifier.ANY,
functools.partial(self._on_event,
reply_to, task_uuid))
elif isinstance(task.notifier, nt.RestrictedNotifier):
# only proxy the allowable events then...
for event_type in task.notifier.events_iter():
task.notifier.register(event_type,
functools.partial(self._on_event,
reply_to, task_uuid))
# perform the task action
try:
result = handler(task, **arguments)
except Exception:
with misc.capture_failure() as failure:
LOG.warn("The '%s' endpoint '%s' execution for request"
" message '%s' failed", endpoint, action,
ku.DelayedPretty(message), exc_info=True)
reply_callback(result=failure.to_dict())
else:
if isinstance(result, ft.Failure):
reply_callback(result=result.to_dict())
else:
reply_callback(state=pr.SUCCESS, result=result)
def start(self):
"""Start processing incoming requests."""
self._proxy.start()
def wait(self):
"""Wait until server is started."""
self._proxy.wait()
def stop(self):
"""Stop processing incoming requests."""
self._proxy.stop()