aodh/ceilometer/collector/service.py
Doug Hellmann b3c2fcfef5 Add docstrings to some methods
Add some docstrings to some methods in the collector
service code to make it easier to understand what they
do.

Change-Id: I67204936dc1373dc73effdbe9a36754e3c952e38
2013-09-11 17:35:36 -04:00

298 lines
11 KiB
Python

# -*- encoding: utf-8 -*-
#
# Copyright © 2012-2013 eNovance <licensing@enovance.com>
#
# Author: Julien Danjou <julien@danjou.info>
#
# 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 msgpack
from oslo.config import cfg
import socket
from stevedore import extension
from stevedore import named
from ceilometer.service import prepare_service
from ceilometer.openstack.common import context
from ceilometer.openstack.common.gettextutils import _
from ceilometer.openstack.common import log
from ceilometer.openstack.common import service as os_service
from ceilometer.openstack.common.rpc import dispatcher as rpc_dispatcher
from ceilometer.openstack.common.rpc import service as rpc_service
from ceilometer.openstack.common import timeutils
from ceilometer import pipeline
from ceilometer import storage
from ceilometer.storage import models
from ceilometer import transformer
OPTS = [
cfg.StrOpt('udp_address',
default='0.0.0.0',
help='address to bind the UDP socket to'
'disabled if set to an empty string'),
cfg.IntOpt('udp_port',
default=4952,
help='port to bind the UDP socket to'),
cfg.BoolOpt('ack_on_event_error',
default=True,
help='Acknowledge message when event persistence fails'),
cfg.BoolOpt('store_events',
default=False,
help='Save event details'),
cfg.MultiStrOpt('dispatcher',
default=['database'],
help='dispatcher to process metering data'),
]
cfg.CONF.register_opts(OPTS, group="collector")
LOG = log.getLogger(__name__)
class UDPCollectorService(os_service.Service):
"""UDP listener for the collector service."""
def __init__(self):
super(UDPCollectorService, self).__init__()
self.storage_conn = storage.get_connection(cfg.CONF)
def start(self):
"""Bind the UDP socket and handle incoming data."""
super(UDPCollectorService, self).start()
udp = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
udp.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
udp.bind((cfg.CONF.collector.udp_address,
cfg.CONF.collector.udp_port))
self.running = True
while self.running:
# NOTE(jd) Arbitrary limit of 64K because that ought to be
# enough for anybody.
data, source = udp.recvfrom(64 * 1024)
try:
counter = msgpack.loads(data)
except Exception:
LOG.warn(_("UDP: Cannot decode data sent by %s"), str(source))
else:
try:
counter['counter_name'] = counter['name']
counter['counter_volume'] = counter['volume']
counter['counter_unit'] = counter['unit']
counter['counter_type'] = counter['type']
LOG.debug("UDP: Storing %s", str(counter))
self.storage_conn.record_metering_data(counter)
except Exception as err:
LOG.debug(_("UDP: Unable to store meter"))
LOG.exception(err)
def stop(self):
self.running = False
super(UDPCollectorService, self).stop()
def udp_collector():
prepare_service()
os_service.launch(UDPCollectorService()).wait()
class UnableToSaveEventException(Exception):
"""Thrown when we want to requeue an event.
Any exception is fine, but this one should make debugging
a little easier.
"""
pass
class CollectorService(rpc_service.Service):
COLLECTOR_NAMESPACE = 'ceilometer.collector'
DISPATCHER_NAMESPACE = 'ceilometer.dispatcher'
def start(self):
super(CollectorService, self).start()
# Add a dummy thread to have wait() working
self.tg.add_timer(604800, lambda: None)
def initialize_service_hook(self, service):
'''Consumers must be declared before consume_thread start.'''
LOG.debug('initialize_service_hooks')
self.pipeline_manager = pipeline.setup_pipeline(
transformer.TransformerExtensionManager(
'ceilometer.transformer',
),
)
LOG.debug('loading notification handlers from %s',
self.COLLECTOR_NAMESPACE)
self.notification_manager = \
extension.ExtensionManager(
namespace=self.COLLECTOR_NAMESPACE,
invoke_on_load=True,
)
if not list(self.notification_manager):
LOG.warning('Failed to load any notification handlers for %s',
self.COLLECTOR_NAMESPACE)
self.notification_manager.map(self._setup_subscription)
LOG.debug('loading dispatchers from %s',
self.DISPATCHER_NAMESPACE)
self.dispatcher_manager = named.NamedExtensionManager(
namespace=self.DISPATCHER_NAMESPACE,
names=cfg.CONF.collector.dispatcher,
invoke_on_load=True,
invoke_args=[cfg.CONF])
if not list(self.dispatcher_manager):
LOG.warning('Failed to load any dispatchers for %s',
self.DISPATCHER_NAMESPACE)
# Set ourselves up as a separate worker for the metering data,
# since the default for service is to use create_consumer().
self.conn.create_worker(
cfg.CONF.publisher_rpc.metering_topic,
rpc_dispatcher.RpcDispatcher([self]),
'ceilometer.collector.' + cfg.CONF.publisher_rpc.metering_topic,
)
def _setup_subscription(self, ext, *args, **kwds):
"""Connect to message bus to get notifications
Configure the RPC connection to listen for messages on the
right exchanges and topics so we receive all of the
notifications.
Use a connection pool so that multiple collector instances can
run in parallel to share load and without competing with each
other for incoming messages.
"""
handler = ext.obj
ack_on_error = cfg.CONF.collector.ack_on_event_error
LOG.debug('Event types from %s: %s (ack_on_error=%s)',
ext.name, ', '.join(handler.event_types),
ack_on_error)
for exchange_topic in handler.get_exchange_topics(cfg.CONF):
for topic in exchange_topic.topics:
try:
self.conn.join_consumer_pool(
callback=self.process_notification,
pool_name=topic,
topic=topic,
exchange_name=exchange_topic.exchange,
ack_on_error=ack_on_error)
except Exception:
LOG.exception('Could not join consumer pool %s/%s' %
(topic, exchange_topic.exchange))
def record_metering_data(self, context, data):
"""RPC endpoint for messages we send to ourself
When the notification messages are re-published through the
RPC publisher, this method receives them for processing.
"""
self.dispatcher_manager.map(self._record_metering_data_for_ext,
context=context,
data=data)
def process_notification(self, notification):
"""RPC endpoint for notification messages
When another service sends a notification over the message
bus, this method receives it. See _setup_subscription().
"""
LOG.debug('notification %r', notification.get('event_type'))
self.notification_manager.map(self._process_notification_for_ext,
notification=notification)
if cfg.CONF.collector.store_events:
self._message_to_event(notification)
@staticmethod
def _extract_when(body):
"""Extract the generated datetime from the notification.
"""
when = body.get('timestamp', body.get('_context_timestamp'))
if when:
return timeutils.normalize_time(timeutils.parse_isotime(when))
return timeutils.utcnow()
def _message_to_event(self, body):
"""Convert message to Ceilometer Event.
NOTE: this is currently based on the Nova notification format.
We will need to make this driver-based to support other formats.
NOTE: the rpc layer currently rips out the notification
delivery_info, which is critical to determining the
source of the notification. This will have to get added back later.
"""
message_id = body.get('message_id')
event_name = body['event_type']
when = self._extract_when(body)
LOG.debug('Saving event "%s"', event_name)
publisher = body.get('publisher_id')
request_id = body.get('_context_request_id')
tenant_id = body.get('_context_tenant')
text = models.Trait.TEXT_TYPE
all_traits = [models.Trait('service', text, publisher),
models.Trait('request_id', text, request_id),
models.Trait('tenant_id', text, tenant_id),
]
# Only store non-None value traits ...
traits = [trait for trait in all_traits if trait.value is not None]
event = models.Event(message_id, event_name, when, traits)
problem_events = []
for dispatcher in self.dispatcher_manager:
problem_events.extend(dispatcher.obj.record_events(event))
if models.Event.UNKNOWN_PROBLEM in [x[0] for x in problem_events]:
# Don't ack the message, raise to requeue it
# if ack_on_error = False
raise UnableToSaveEventException()
@staticmethod
def _record_metering_data_for_ext(ext, context, data):
"""Wrapper for calling dispatcher plugin when a sample arrives
When a message is received by record_metering_data(), it calls
this method with each plugin to allow it to process the data.
"""
ext.obj.record_metering_data(context, data)
def _process_notification_for_ext(self, ext, notification):
"""Wrapper for calling pipelines when a notification arrives
When a message is received by process_notification(), it calls
this method with each notification plugin to allow all the
plugins process the notification.
"""
with self.pipeline_manager.publisher(context.get_admin_context()) as p:
# FIXME(dhellmann): Spawn green thread?
p(list(ext.obj.to_samples(notification)))
def collector():
prepare_service()
os_service.launch(CollectorService(cfg.CONF.host,
'ceilometer.collector')).wait()