![Thomas Bechtold](/assets/img/avatar_default.png)
oslo.service replaces the loopingcall code from oslo-incubator so switch to the new oslo.service module. Change-Id: Iba8a86cc79f8bbda4b04c71568dd9a33f4ace6f6
624 lines
21 KiB
Python
624 lines
21 KiB
Python
# Copyright 2010 United States Government as represented by the
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# Administrator of the National Aeronautics and Space Administration.
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# Copyright 2011 Justin Santa Barbara
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""Generic Node base class for all workers that run on hosts."""
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import errno
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import inspect
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import os
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import random
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import signal
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import sys
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import time
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import eventlet
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import greenlet
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from oslo_config import cfg
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from oslo_log import log
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import oslo_messaging as messaging
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from oslo_service import loopingcall
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from oslo_utils import importutils
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from manila import context
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from manila import db
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from manila import exception
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from manila.i18n import _LE
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from manila.i18n import _LI
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from manila.i18n import _LW
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from manila import rpc
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from manila import version
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from manila import wsgi
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LOG = log.getLogger(__name__)
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service_opts = [
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cfg.IntOpt('report_interval',
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default=10,
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help='Seconds between nodes reporting state to datastore.'),
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cfg.IntOpt('periodic_interval',
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default=60,
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help='Seconds between running periodic tasks.'),
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cfg.IntOpt('periodic_fuzzy_delay',
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default=60,
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help='Range of seconds to randomly delay when starting the '
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'periodic task scheduler to reduce stampeding. '
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'(Disable by setting to 0)'),
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cfg.StrOpt('osapi_share_listen',
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default="0.0.0.0",
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help='IP address for OpenStack Share API to listen on.'),
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cfg.IntOpt('osapi_share_listen_port',
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default=8786,
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help='Port for OpenStack Share API to listen on.'), ]
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CONF = cfg.CONF
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CONF.register_opts(service_opts)
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class SignalExit(SystemExit):
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def __init__(self, signo, exccode=1):
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super(SignalExit, self).__init__(exccode)
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self.signo = signo
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class Launcher(object):
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"""Launch one or more services and wait for them to complete."""
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def __init__(self):
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"""Initialize the service launcher.
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:returns: None
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"""
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self._services = []
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@staticmethod
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def run_server(server):
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"""Start and wait for a server to finish.
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:param service: Server to run and wait for.
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:returns: None
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"""
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server.start()
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server.wait()
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def launch_server(self, server):
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"""Load and start the given server.
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:param server: The server you would like to start.
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:returns: None
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"""
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gt = eventlet.spawn(self.run_server, server)
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self._services.append(gt)
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def stop(self):
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"""Stop all services which are currently running.
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:returns: None
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"""
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for service in self._services:
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service.kill()
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def wait(self):
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"""Waits until all services have been stopped, and then returns.
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:returns: None
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"""
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def sigterm(sig, frame):
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LOG.info(_LI("SIGTERM received"))
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# NOTE(jk0): Raise a ^C which is caught by the caller and cleanly
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# shuts down the service. This does not yet handle eventlet
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# threads.
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raise KeyboardInterrupt
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signal.signal(signal.SIGTERM, sigterm)
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for service in self._services:
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try:
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service.wait()
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except greenlet.GreenletExit:
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pass
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class ServerWrapper(object):
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def __init__(self, server, workers):
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self.server = server
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self.workers = workers
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self.children = set()
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self.forktimes = []
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self.failed = False
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class ProcessLauncher(object):
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def __init__(self):
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self.children = {}
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self.sigcaught = None
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self.totalwrap = 0
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self.failedwrap = 0
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self.running = True
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rfd, self.writepipe = os.pipe()
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self.readpipe = eventlet.greenio.GreenPipe(rfd, 'r')
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signal.signal(signal.SIGTERM, self._handle_signal)
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signal.signal(signal.SIGINT, self._handle_signal)
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def _handle_signal(self, signo, frame):
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self.sigcaught = signo
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self.running = False
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# Allow the process to be killed again and die from natural causes
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signal.signal(signal.SIGTERM, signal.SIG_DFL)
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signal.signal(signal.SIGINT, signal.SIG_DFL)
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def _pipe_watcher(self):
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# This will block until the write end is closed when the parent
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# dies unexpectedly
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self.readpipe.read()
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LOG.info(_LI('Parent process has died unexpectedly, exiting'))
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sys.exit(1)
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def _child_process(self, server):
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# Setup child signal handlers differently
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def _sigterm(*args):
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signal.signal(signal.SIGTERM, signal.SIG_DFL)
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raise SignalExit(signal.SIGTERM)
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signal.signal(signal.SIGTERM, _sigterm)
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# Block SIGINT and let the parent send us a SIGTERM
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# signal.signal(signal.SIGINT, signal.SIG_IGN)
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# This differs from the behavior in nova in that we dont ignore this
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# It allows the non-wsgi services to be terminated properly
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signal.signal(signal.SIGINT, _sigterm)
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# Reopen the eventlet hub to make sure we don't share an epoll
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# fd with parent and/or siblings, which would be bad
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eventlet.hubs.use_hub()
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# Close write to ensure only parent has it open
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os.close(self.writepipe)
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# Create greenthread to watch for parent to close pipe
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eventlet.spawn(self._pipe_watcher)
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# Reseed random number generator
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random.seed()
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launcher = Launcher()
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launcher.run_server(server)
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def _start_child(self, wrap):
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if len(wrap.forktimes) > wrap.workers:
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# Limit ourselves to one process a second (over the period of
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# number of workers * 1 second). This will allow workers to
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# start up quickly but ensure we don't fork off children that
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# die instantly too quickly.
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if time.time() - wrap.forktimes[0] < wrap.workers:
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LOG.info(_LI('Forking too fast, sleeping'))
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time.sleep(1)
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wrap.forktimes.pop(0)
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wrap.forktimes.append(time.time())
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pid = os.fork()
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if pid == 0:
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# NOTE(johannes): All exceptions are caught to ensure this
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# doesn't fallback into the loop spawning children. It would
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# be bad for a child to spawn more children.
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status = 0
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try:
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self._child_process(wrap.server)
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except SignalExit as exc:
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signame = {signal.SIGTERM: 'SIGTERM',
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signal.SIGINT: 'SIGINT'}[exc.signo]
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LOG.info(_LI('Caught %s, exiting'), signame)
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status = exc.code
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except SystemExit as exc:
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status = exc.code
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except BaseException:
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LOG.exception(_LE('Unhandled exception'))
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status = 2
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finally:
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wrap.server.stop()
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os._exit(status)
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LOG.info(_LI('Started child %d'), pid)
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wrap.children.add(pid)
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self.children[pid] = wrap
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return pid
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def launch_server(self, server, workers=1):
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wrap = ServerWrapper(server, workers)
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self.totalwrap = self.totalwrap + 1
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LOG.info(_LI('Starting %d workers'), wrap.workers)
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while (self.running and len(wrap.children) < wrap.workers
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and not wrap.failed):
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self._start_child(wrap)
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def _wait_child(self):
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try:
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# Don't block if no child processes have exited
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pid, status = os.waitpid(0, os.WNOHANG)
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if not pid:
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return None
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except OSError as exc:
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if exc.errno not in (errno.EINTR, errno.ECHILD):
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raise
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return None
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code = 0
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if os.WIFSIGNALED(status):
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sig = os.WTERMSIG(status)
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LOG.info(_LI('Child %(pid)d killed by signal %(sig)d'),
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{'pid': pid, 'sig': sig})
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else:
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code = os.WEXITSTATUS(status)
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LOG.info(_LI('Child %(pid)d exited with status %(code)d'),
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{'pid': pid, 'code': code})
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if pid not in self.children:
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LOG.warning(_LW('pid %d not in child list'), pid)
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return None
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wrap = self.children.pop(pid)
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wrap.children.remove(pid)
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if 2 == code:
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wrap.failed = True
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self.failedwrap = self.failedwrap + 1
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LOG.info(_LI('_wait_child %d'), self.failedwrap)
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if self.failedwrap == self.totalwrap:
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self.running = False
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return wrap
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def wait(self):
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"""Loop waiting on children to die and respawning as necessary."""
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while self.running:
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wrap = self._wait_child()
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if not wrap:
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# Yield to other threads if no children have exited
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# Sleep for a short time to avoid excessive CPU usage
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# (see bug #1095346)
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eventlet.greenthread.sleep(.01)
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continue
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LOG.info(_LI('wait wrap.failed %s'), wrap.failed)
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while (self.running and len(wrap.children) < wrap.workers
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and not wrap.failed):
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self._start_child(wrap)
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if self.sigcaught:
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signame = {signal.SIGTERM: 'SIGTERM',
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signal.SIGINT: 'SIGINT'}[self.sigcaught]
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LOG.info(_LI('Caught %s, stopping children'), signame)
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for pid in self.children:
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try:
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os.kill(pid, signal.SIGTERM)
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except OSError as exc:
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if exc.errno != errno.ESRCH:
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raise
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# Wait for children to die
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if self.children:
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LOG.info(_LI('Waiting on %d children to exit'), len(self.children))
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while self.children:
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self._wait_child()
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class Service(object):
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"""Service object for binaries running on hosts.
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A service takes a manager and enables rpc by listening to queues based
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on topic. It also periodically runs tasks on the manager and reports
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it state to the database services table.
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"""
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def __init__(self, host, binary, topic, manager, report_interval=None,
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periodic_interval=None, periodic_fuzzy_delay=None,
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service_name=None, *args, **kwargs):
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super(Service, self).__init__()
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if not rpc.initialized():
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rpc.init(CONF)
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self.host = host
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self.binary = binary
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self.topic = topic
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self.manager_class_name = manager
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manager_class = importutils.import_class(self.manager_class_name)
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self.manager = manager_class(host=self.host,
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service_name=service_name,
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*args, **kwargs)
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self.report_interval = report_interval
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self.periodic_interval = periodic_interval
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self.periodic_fuzzy_delay = periodic_fuzzy_delay
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self.saved_args, self.saved_kwargs = args, kwargs
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self.timers = []
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def start(self):
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version_string = version.version_string()
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LOG.info(_LI('Starting %(topic)s node (version %(version_string)s)'),
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{'topic': self.topic, 'version_string': version_string})
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self.model_disconnected = False
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ctxt = context.get_admin_context()
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try:
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service_ref = db.service_get_by_args(ctxt,
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self.host,
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self.binary)
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self.service_id = service_ref['id']
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except exception.NotFound:
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self._create_service_ref(ctxt)
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LOG.debug("Creating RPC server for service %s.", self.topic)
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target = messaging.Target(topic=self.topic, server=self.host)
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endpoints = [self.manager]
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endpoints.extend(self.manager.additional_endpoints)
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self.rpcserver = rpc.get_server(target, endpoints)
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self.rpcserver.start()
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self.manager.init_host()
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if self.report_interval:
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pulse = loopingcall.FixedIntervalLoopingCall(self.report_state)
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pulse.start(interval=self.report_interval,
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initial_delay=self.report_interval)
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self.timers.append(pulse)
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if self.periodic_interval:
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if self.periodic_fuzzy_delay:
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initial_delay = random.randint(0, self.periodic_fuzzy_delay)
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else:
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initial_delay = None
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periodic = loopingcall.FixedIntervalLoopingCall(
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self.periodic_tasks)
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periodic.start(interval=self.periodic_interval,
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initial_delay=initial_delay)
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self.timers.append(periodic)
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def _create_service_ref(self, context):
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zone = CONF.storage_availability_zone
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service_ref = db.service_create(context,
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{'host': self.host,
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'binary': self.binary,
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'topic': self.topic,
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'report_count': 0,
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'availability_zone': zone})
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self.service_id = service_ref['id']
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def __getattr__(self, key):
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manager = self.__dict__.get('manager', None)
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return getattr(manager, key)
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@classmethod
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def create(cls, host=None, binary=None, topic=None, manager=None,
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report_interval=None, periodic_interval=None,
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periodic_fuzzy_delay=None, service_name=None):
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"""Instantiates class and passes back application object.
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:param host: defaults to CONF.host
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:param binary: defaults to basename of executable
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:param topic: defaults to bin_name - 'manila-' part
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:param manager: defaults to CONF.<topic>_manager
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:param report_interval: defaults to CONF.report_interval
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:param periodic_interval: defaults to CONF.periodic_interval
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:param periodic_fuzzy_delay: defaults to CONF.periodic_fuzzy_delay
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"""
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if not host:
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host = CONF.host
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if not binary:
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binary = os.path.basename(inspect.stack()[-1][1])
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if not topic:
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topic = binary
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if not manager:
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subtopic = topic.rpartition('manila-')[2]
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manager = CONF.get('%s_manager' % subtopic, None)
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if report_interval is None:
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report_interval = CONF.report_interval
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if periodic_interval is None:
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periodic_interval = CONF.periodic_interval
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if periodic_fuzzy_delay is None:
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periodic_fuzzy_delay = CONF.periodic_fuzzy_delay
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service_obj = cls(host, binary, topic, manager,
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report_interval=report_interval,
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periodic_interval=periodic_interval,
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periodic_fuzzy_delay=periodic_fuzzy_delay,
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service_name=service_name)
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return service_obj
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def kill(self):
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"""Destroy the service object in the datastore."""
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self.stop()
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try:
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db.service_destroy(context.get_admin_context(), self.service_id)
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except exception.NotFound:
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LOG.warn(_LW('Service killed that has no database entry'))
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def stop(self):
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# Try to shut the connection down, but if we get any sort of
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# errors, go ahead and ignore them.. as we're shutting down anyway
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try:
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self.rpcserver.stop()
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except Exception:
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pass
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for x in self.timers:
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try:
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x.stop()
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except Exception:
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pass
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self.timers = []
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def wait(self):
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for x in self.timers:
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try:
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x.wait()
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except Exception:
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pass
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def periodic_tasks(self, raise_on_error=False):
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"""Tasks to be run at a periodic interval."""
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ctxt = context.get_admin_context()
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self.manager.periodic_tasks(ctxt, raise_on_error=raise_on_error)
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def report_state(self):
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"""Update the state of this service in the datastore."""
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ctxt = context.get_admin_context()
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zone = CONF.storage_availability_zone
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state_catalog = {}
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try:
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try:
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service_ref = db.service_get(ctxt, self.service_id)
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except exception.NotFound:
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LOG.debug('The service database object disappeared, '
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'Recreating it.')
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self._create_service_ref(ctxt)
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service_ref = db.service_get(ctxt, self.service_id)
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state_catalog['report_count'] = service_ref['report_count'] + 1
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if zone != service_ref['availability_zone']:
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state_catalog['availability_zone'] = zone
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db.service_update(ctxt,
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self.service_id, state_catalog)
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# TODO(termie): make this pattern be more elegant.
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if getattr(self, 'model_disconnected', False):
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self.model_disconnected = False
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LOG.error(_LE('Recovered model server connection!'))
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# TODO(vish): this should probably only catch connection errors
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except Exception: # pylint: disable=W0702
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if not getattr(self, 'model_disconnected', False):
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self.model_disconnected = True
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LOG.exception(_LE('model server went away'))
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class WSGIService(object):
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"""Provides ability to launch API from a 'paste' configuration."""
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def __init__(self, name, loader=None):
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"""Initialize, but do not start the WSGI server.
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:param name: The name of the WSGI server given to the loader.
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:param loader: Loads the WSGI application using the given name.
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:returns: None
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"""
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self.name = name
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self.manager = self._get_manager()
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self.loader = loader or wsgi.Loader()
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if not rpc.initialized():
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rpc.init(CONF)
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self.app = self.loader.load_app(name)
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self.host = getattr(CONF, '%s_listen' % name, "0.0.0.0")
|
|
self.port = getattr(CONF, '%s_listen_port' % name, 0)
|
|
self.server = wsgi.Server(name,
|
|
self.app,
|
|
host=self.host,
|
|
port=self.port)
|
|
|
|
def _get_manager(self):
|
|
"""Initialize a Manager object appropriate for this service.
|
|
|
|
Use the service name to look up a Manager subclass from the
|
|
configuration and initialize an instance. If no class name
|
|
is configured, just return None.
|
|
|
|
:returns: a Manager instance, or None.
|
|
|
|
"""
|
|
fl = '%s_manager' % self.name
|
|
if fl not in CONF:
|
|
return None
|
|
|
|
manager_class_name = CONF.get(fl, None)
|
|
if not manager_class_name:
|
|
return None
|
|
|
|
manager_class = importutils.import_class(manager_class_name)
|
|
return manager_class()
|
|
|
|
def start(self):
|
|
"""Start serving this service using loaded configuration.
|
|
|
|
Also, retrieve updated port number in case '0' was passed in, which
|
|
indicates a random port should be used.
|
|
|
|
:returns: None
|
|
|
|
"""
|
|
if self.manager:
|
|
self.manager.init_host()
|
|
self.server.start()
|
|
self.port = self.server.port
|
|
|
|
def stop(self):
|
|
"""Stop serving this API.
|
|
|
|
:returns: None
|
|
|
|
"""
|
|
self.server.stop()
|
|
|
|
def wait(self):
|
|
"""Wait for the service to stop serving this API.
|
|
|
|
:returns: None
|
|
|
|
"""
|
|
self.server.wait()
|
|
|
|
|
|
# NOTE(vish): the global launcher is to maintain the existing
|
|
# functionality of calling service.serve +
|
|
# service.wait
|
|
_launcher = None
|
|
|
|
|
|
def serve(*servers):
|
|
global _launcher
|
|
if not _launcher:
|
|
_launcher = Launcher()
|
|
for server in servers:
|
|
_launcher.launch_server(server)
|
|
|
|
|
|
def wait():
|
|
LOG.debug('Full set of CONF:')
|
|
for flag in CONF:
|
|
flag_get = CONF.get(flag, None)
|
|
# hide flag contents from log if contains a password
|
|
# should use secret flag when switch over to openstack-common
|
|
if ("_password" in flag or "_key" in flag or
|
|
(flag == "sql_connection" and "mysql:" in flag_get)):
|
|
LOG.debug('%(flag)s : FLAG SET ', {"flag": flag})
|
|
else:
|
|
LOG.debug('%(flag)s : %(flag_get)s',
|
|
{"flag": flag, "flag_get": flag_get})
|
|
try:
|
|
_launcher.wait()
|
|
except KeyboardInterrupt:
|
|
_launcher.stop()
|
|
rpc.cleanup()
|