neutron-lib/neutron_lib/worker.py
Doug Wiegley 2c1e09bfd5
Add setproctitle support to the workers module
- Set the process name of child neutron-servers to be something more
  readily identifiable than today.
- Enable by default for all users of the workers module, neutron will
  have a conf setting for its workers.

Matching neutron change:
https://review.openstack.org/637019

Partial-Bug: #1816485
Depends-On: https://review.openstack.org/637024
Change-Id: Ic6eca08f2ccacb3f8bf741c47a45e88cd3877b29
2019-02-18 13:38:48 -07:00

108 lines
3.7 KiB
Python

# 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
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# 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
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# under the License.
import os
from oslo_service import service
import setproctitle
from neutron_lib.callbacks import events
from neutron_lib.callbacks import registry
from neutron_lib.callbacks import resources
class BaseWorker(service.ServiceBase):
"""Partial implementation of the ServiceBase ABC.
Subclasses will still need to add the other abstract methods defined in
service.ServiceBase. See oslo_service for more details.
If a plugin needs to handle synchronization with the Neutron database and
do this only once instead of in every API worker, for instance, it would
define a BaseWorker class and the plugin would have get_workers return
an array of BaseWorker instances. For example:
.. code-block:: python
class MyPlugin(...):
def get_workers(self):
return [MyPluginWorker()]
class MyPluginWorker(BaseWorker):
def start(self):
super(MyPluginWorker, self).start()
do_sync()
"""
# default class value for case when super().__init__ is not called
_default_process_count = 1
def __init__(self, worker_process_count=_default_process_count,
set_proctitle='on'):
"""Initialize a worker instance.
:param worker_process_count: Defines how many processes to spawn for
worker:
0 - spawn 1 new worker thread,
1..N - spawn N new worker processes
set_proctitle:
'off' - do not change process title
'on' - set process title to descriptive string and parent
'brief' - set process title to descriptive string
"""
self._worker_process_count = worker_process_count
self._my_pid = os.getpid()
self._set_proctitle = set_proctitle
if set_proctitle == 'on':
self._parent_proctitle = setproctitle.getproctitle()
@property
def worker_process_count(self):
"""The worker's process count.
:returns: The number of processes to spawn for this worker.
"""
return self._worker_process_count
def setproctitle(self, name="neutron-server", desc=None):
if self._set_proctitle == "off" or os.getpid() == self._my_pid:
return
if not desc:
desc = self.__class__.__name__
proctitle = "%s: %s" % (name, desc)
if self._set_proctitle == "on":
proctitle += " (%s)" % self._parent_proctitle
setproctitle.setproctitle(proctitle)
def start(self, name="neutron-server", desc=None):
"""Start the worker.
If worker_process_count is greater than 0, a callback notification
is sent. Subclasses should call this method before doing their
own start() work.
Automatically sets the process title to indicate that this is a
child worker, customizable via the name and desc arguments.
:returns: None
"""
# If we are a child process, set our proctitle to something useful
self.setproctitle(name, desc)
if self.worker_process_count > 0:
registry.notify(resources.PROCESS, events.AFTER_INIT, self.start)