14ecaa4550
Since asserts can be silenced using -0 and/or compiled out we want to be more strict here and raise value errors when the expected callable objects/functions are not actually callable. Change-Id: Ib14e2e7329dbfcce50660f144ad4780d99f36854
121 lines
5.2 KiB
Python
121 lines
5.2 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 logging
|
|
|
|
from kombu import exceptions as kombu_exc
|
|
import six
|
|
|
|
from taskflow import exceptions as excp
|
|
|
|
LOG = logging.getLogger(__name__)
|
|
|
|
|
|
class TypeDispatcher(object):
|
|
"""Receives messages and dispatches to type specific handlers."""
|
|
|
|
def __init__(self, type_handlers):
|
|
self._handlers = dict(type_handlers)
|
|
self._requeue_filters = []
|
|
|
|
def add_requeue_filter(self, callback):
|
|
"""Add a callback that can *request* message requeuing.
|
|
|
|
The callback will be activated before the message has been acked and
|
|
it can be used to instruct the dispatcher to requeue the message
|
|
instead of processing it. The callback, when called, will be provided
|
|
two positional parameters; the first being the message data and the
|
|
second being the message object. Using these provided parameters the
|
|
filter should return a truthy object if the message should be requeued
|
|
and a falsey object if it should not.
|
|
"""
|
|
if not six.callable(callback):
|
|
raise ValueError("Requeue filter callback must be callable")
|
|
self._requeue_filters.append(callback)
|
|
|
|
def _collect_requeue_votes(self, data, message):
|
|
# Returns how many of the filters asked for the message to be requeued.
|
|
requeue_votes = 0
|
|
for i, cb in enumerate(self._requeue_filters):
|
|
try:
|
|
if cb(data, message):
|
|
requeue_votes += 1
|
|
except Exception:
|
|
LOG.exception("Failed calling requeue filter %s '%s' to"
|
|
" determine if message %r should be requeued.",
|
|
i + 1, cb, message.delivery_tag)
|
|
return requeue_votes
|
|
|
|
def _requeue_log_error(self, message, errors):
|
|
# TODO(harlowja): Remove when http://github.com/celery/kombu/pull/372
|
|
# is merged and a version is released with this change...
|
|
try:
|
|
message.requeue()
|
|
except errors as exc:
|
|
# This was taken from how kombu is formatting its messages
|
|
# when its reject_log_error or ack_log_error functions are
|
|
# used so that we have a similar error format for requeuing.
|
|
LOG.critical("Couldn't requeue %r, reason:%r",
|
|
message.delivery_tag, exc, exc_info=True)
|
|
else:
|
|
LOG.debug("AMQP message %r requeued.", message.delivery_tag)
|
|
|
|
def _process_message(self, data, message, message_type):
|
|
handler = self._handlers.get(message_type)
|
|
if handler is None:
|
|
message.reject_log_error(logger=LOG,
|
|
errors=(kombu_exc.MessageStateError,))
|
|
LOG.warning("Unexpected message type: '%s' in message"
|
|
" %r", message_type, message.delivery_tag)
|
|
else:
|
|
if isinstance(handler, (tuple, list)):
|
|
handler, validator = handler
|
|
try:
|
|
validator(data)
|
|
except excp.InvalidFormat as e:
|
|
message.reject_log_error(
|
|
logger=LOG, errors=(kombu_exc.MessageStateError,))
|
|
LOG.warn("Message: %r, '%s' was rejected due to it being"
|
|
" in an invalid format: %s",
|
|
message.delivery_tag, message_type, e)
|
|
return
|
|
message.ack_log_error(logger=LOG,
|
|
errors=(kombu_exc.MessageStateError,))
|
|
if message.acknowledged:
|
|
LOG.debug("AMQP message %r acknowledged.",
|
|
message.delivery_tag)
|
|
handler(data, message)
|
|
else:
|
|
message.reject_log_error(logger=LOG,
|
|
errors=(kombu_exc.MessageStateError,))
|
|
|
|
def on_message(self, data, message):
|
|
"""This method is called on incoming messages."""
|
|
LOG.debug("Got message: %r", message.delivery_tag)
|
|
if self._collect_requeue_votes(data, message):
|
|
self._requeue_log_error(message,
|
|
errors=(kombu_exc.MessageStateError,))
|
|
else:
|
|
try:
|
|
message_type = message.properties['type']
|
|
except KeyError:
|
|
message.reject_log_error(
|
|
logger=LOG, errors=(kombu_exc.MessageStateError,))
|
|
LOG.warning("The 'type' message property is missing"
|
|
" in message %r", message.delivery_tag)
|
|
else:
|
|
self._process_message(data, message, message_type)
|