Source code for monasca_log_api.reference.common.log_publisher
# Copyright 2015 kornicameister@gmail.com
# Copyright 2016 FUJITSU LIMITED
#
# 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 falcon
import time
from monasca_common.kafka import producer
from monasca_common.rest import utils as rest_utils
from oslo_config import cfg
from oslo_log import log
from monasca_log_api.monitoring import client
from monasca_log_api.monitoring import metrics
from monasca_log_api.reference.common import model
LOG = log.getLogger(__name__)
CONF = cfg.CONF
_MAX_MESSAGE_SIZE = 1048576
_RETRY_AFTER = 60
_TIMESTAMP_KEY_SIZE = len(
bytearray(str(int(time.time() * 1000)).encode('utf-8')))
_TRUNCATED_PROPERTY_SIZE = len(
bytearray('"truncated": true'.encode('utf-8')))
_KAFKA_META_DATA_SIZE = 32
_TRUNCATION_SAFE_OFFSET = 1
log_publisher_opts = [
cfg.StrOpt('kafka_url',
required=True,
help='Url to kafka server'),
cfg.MultiStrOpt('topics',
default=['logs'],
help='Consumer topics'),
cfg.IntOpt('max_message_size',
default=_MAX_MESSAGE_SIZE,
required=True,
help=('Message max size that can be sent '
'to kafka, default to %d bytes' % _MAX_MESSAGE_SIZE))
]
log_publisher_group = cfg.OptGroup(name='log_publisher', title='log_publisher')
cfg.CONF.register_group(log_publisher_group)
cfg.CONF.register_opts(log_publisher_opts, log_publisher_group)
[docs]class InvalidMessageException(Exception):
pass
[docs]class LogPublisher(object):
"""Publishes log data to Kafka
LogPublisher is able to send single message to multiple configured topic.
It uses following configuration written in conf file ::
[log_publisher]
topics = 'logs'
kafka_url = 'localhost:8900'
Note:
Uses :py:class:`monasca_common.kafka.producer.KafkaProducer`
to ship logs to kafka. For more details
see `monasca_common`_ github repository.
.. _monasca_common: https://github.com/openstack/monasca-common
"""
def __init__(self):
self._topics = CONF.log_publisher.topics
self.max_message_size = CONF.log_publisher.max_message_size
self._kafka_publisher = producer.KafkaProducer(
url=CONF.log_publisher.kafka_url
)
self._statsd = client.get_client()
# setup counter, gauges etc
self._logs_published_counter = self._statsd.get_counter(
metrics.LOGS_PUBLISHED_METRIC
)
self._publish_time_ms = self._statsd.get_timer(
metrics.LOGS_PUBLISH_TIME_METRIC
)
self._logs_lost_counter = self._statsd.get_counter(
metrics.LOGS_PUBLISHED_LOST_METRIC
)
self._logs_truncated_gauge = self._statsd.get_gauge(
metrics.LOGS_TRUNCATED_METRIC
)
LOG.info('Initializing LogPublisher <%s>', self)
[docs] def send_message(self, messages):
"""Sends message to each configured topic.
Note:
Falsy messages (i.e. empty) are not shipped to kafka
See also
* :py:class:`monasca_log_api.common.model.Envelope`
* :py:meth:`._is_message_valid`
:param dict|list messages: instance (or instances) of log envelope
"""
if not messages:
return
if not isinstance(messages, list):
messages = [messages]
sent_counter = 0
num_of_msgs = len(messages)
LOG.debug('About to publish %d messages to %s topics',
num_of_msgs, self._topics)
try:
send_messages = []
for message in messages:
msg = self._transform_message(message)
send_messages.append(msg)
with self._publish_time_ms.time(name=None):
self._publish(send_messages)
sent_counter = len(send_messages)
except Exception as ex:
LOG.error('Failure in publishing messages to kafka')
LOG.exception(ex)
raise ex
finally:
self._after_publish(sent_counter, num_of_msgs)
def _transform_message(self, message):
"""Transforms message into JSON.
Method executes transformation operation for
single element. Operation is set of following
operations:
* checking if message is valid
(:py:func:`.LogPublisher._is_message_valid`)
* truncating message if necessary
(:py:func:`.LogPublisher._truncate`)
:param model.Envelope message: instance of message
:return: serialized message
:rtype: str
"""
if not self._is_message_valid(message):
raise InvalidMessageException()
return self._truncate(message)
def _truncate(self, envelope):
"""Truncates the message if needed.
Each message send to kafka is verified.
Method checks if message serialized to json
exceeds maximum allowed size that can be posted to kafka
queue. If so, method truncates message property of the log
by difference between message and allowed size.
:param Envelope envelope: original envelope
:return: serialized message
:rtype: str
"""
msg_str = rest_utils.as_json(envelope)
envelope_size = ((len(bytearray(msg_str)) +
_TIMESTAMP_KEY_SIZE +
_KAFKA_META_DATA_SIZE)
if msg_str is not None else -1)
diff_size = ((envelope_size - self.max_message_size) +
_TRUNCATION_SAFE_OFFSET)
if diff_size > 1:
truncated_by = diff_size + _TRUNCATED_PROPERTY_SIZE
LOG.warn(('Detected message that exceeds %d bytes,'
'message will be truncated by %d bytes'),
self.max_message_size,
truncated_by)
log_msg = envelope['log']['message']
truncated_log_msg = log_msg[:-truncated_by]
envelope['log']['truncated'] = True
envelope['log']['message'] = truncated_log_msg
self._logs_truncated_gauge.send(name=None, value=truncated_by)
msg_str = rest_utils.as_json(envelope)
else:
self._logs_truncated_gauge.send(name=None, value=0)
return msg_str
def _publish(self, messages):
"""Publishes messages to kafka.
:param list messages: list of messages
"""
num_of_msg = len(messages)
LOG.debug('Publishing %d messages', num_of_msg)
try:
for topic in self._topics:
self._kafka_publisher.publish(
topic,
messages
)
LOG.debug('Sent %d messages to topic %s', num_of_msg, topic)
except Exception as ex:
raise falcon.HTTPServiceUnavailable('Service unavailable',
ex.message, 60)
@staticmethod
def _is_message_valid(message):
"""Validates message before sending.
Methods checks if message is :py:class:`model.Envelope`.
By being instance of this class it is ensured that all required
keys are found and they will have their values.
"""
return message and isinstance(message, model.Envelope)
def _after_publish(self, send_count, to_send_count):
"""Executed after publishing to sent metrics.
:param int send_count: how many messages have been sent
:param int to_send_count: how many messages should be sent
"""
failed_to_send = to_send_count - send_count
if failed_to_send == 0:
LOG.debug('Successfully published all [%d] messages',
send_count)
else:
error_str = ('Failed to send all messages, %d '
'messages out of %d have not been published')
LOG.error(error_str, failed_to_send, to_send_count)
self._logs_published_counter.increment(value=send_count)
self._logs_lost_counter.increment(value=failed_to_send)