Add service.py from openstack-common

and all it's deps

Change-Id: I9932a12bb011c86479b363b6e5a591969f77582b
This commit is contained in:
Angus Salkeld 2012-11-01 13:28:47 +11:00
parent 4c43441d9d
commit 0a36c4c738
5 changed files with 615 additions and 1 deletions

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# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright (c) 2012 Openstack, LLC.
# Administrator of the National Aeronautics and Space Administration.
# 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 gc
import pprint
import sys
import traceback
import eventlet
import eventlet.backdoor
import greenlet
from ceilometer.openstack.common import cfg
eventlet_backdoor_opts = [
cfg.IntOpt('backdoor_port',
default=None,
help='port for eventlet backdoor to listen')
]
CONF = cfg.CONF
CONF.register_opts(eventlet_backdoor_opts)
def _dont_use_this():
print "Don't use this, just disconnect instead"
def _find_objects(t):
return filter(lambda o: isinstance(o, t), gc.get_objects())
def _print_greenthreads():
for i, gt in enumerate(find_objects(greenlet.greenlet)):
print i, gt
traceback.print_stack(gt.gr_frame)
print
def initialize_if_enabled():
backdoor_locals = {
'exit': _dont_use_this, # So we don't exit the entire process
'quit': _dont_use_this, # So we don't exit the entire process
'fo': _find_objects,
'pgt': _print_greenthreads,
}
if CONF.backdoor_port is None:
return
# NOTE(johannes): The standard sys.displayhook will print the value of
# the last expression and set it to __builtin__._, which overwrites
# the __builtin__._ that gettext sets. Let's switch to using pprint
# since it won't interact poorly with gettext, and it's easier to
# read the output too.
def displayhook(val):
if val is not None:
pprint.pprint(val)
sys.displayhook = displayhook
eventlet.spawn(eventlet.backdoor.backdoor_server,
eventlet.listen(('localhost', CONF.backdoor_port)),
locals=backdoor_locals)

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# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# Copyright 2011 Justin Santa Barbara
# 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 sys
from eventlet import event
from eventlet import greenthread
from ceilometer.openstack.common.gettextutils import _
from ceilometer.openstack.common import log as logging
LOG = logging.getLogger(__name__)
class LoopingCallDone(Exception):
"""Exception to break out and stop a LoopingCall.
The poll-function passed to LoopingCall can raise this exception to
break out of the loop normally. This is somewhat analogous to
StopIteration.
An optional return-value can be included as the argument to the exception;
this return-value will be returned by LoopingCall.wait()
"""
def __init__(self, retvalue=True):
""":param retvalue: Value that LoopingCall.wait() should return."""
self.retvalue = retvalue
class LoopingCall(object):
def __init__(self, f=None, *args, **kw):
self.args = args
self.kw = kw
self.f = f
self._running = False
def start(self, interval, initial_delay=None):
self._running = True
done = event.Event()
def _inner():
if initial_delay:
greenthread.sleep(initial_delay)
try:
while self._running:
self.f(*self.args, **self.kw)
if not self._running:
break
greenthread.sleep(interval)
except LoopingCallDone, e:
self.stop()
done.send(e.retvalue)
except Exception:
LOG.exception(_('in looping call'))
done.send_exception(*sys.exc_info())
return
else:
done.send(True)
self.done = done
greenthread.spawn(_inner)
return self.done
def stop(self):
self._running = False
def wait(self):
return self.done.wait()

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# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# Copyright 2011 Justin Santa Barbara
# 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.
"""Generic Node base class for all workers that run on hosts."""
import errno
import os
import random
import signal
import sys
import time
import eventlet
import greenlet
import logging as std_logging
from ceilometer.openstack.common import cfg
from ceilometer.openstack.common import eventlet_backdoor
from ceilometer.openstack.common.gettextutils import _
from ceilometer.openstack.common import log as logging
from ceilometer.openstack.common import threadgroup
try:
from ceilometer.openstack.common import rpc
except ImportError:
rpc = None
CONF = cfg.CONF
LOG = logging.getLogger(__name__)
class Launcher(object):
"""Launch one or more services and wait for them to complete."""
def __init__(self):
"""Initialize the service launcher.
:returns: None
"""
self._services = []
eventlet_backdoor.initialize_if_enabled()
@staticmethod
def run_service(service):
"""Start and wait for a service to finish.
:param service: service to run and wait for.
:returns: None
"""
service.start()
service.wait()
def launch_service(self, service):
"""Load and start the given service.
:param service: The service you would like to start.
:returns: None
"""
gt = eventlet.spawn(self.run_service, service)
self._services.append(gt)
def stop(self):
"""Stop all services which are currently running.
:returns: None
"""
for service in self._services:
service.kill()
def wait(self):
"""Waits until all services have been stopped, and then returns.
:returns: None
"""
for service in self._services:
try:
service.wait()
except greenlet.GreenletExit:
pass
class SignalExit(SystemExit):
def __init__(self, signo, exccode=1):
super(SignalExit, self).__init__(exccode)
self.signo = signo
class ServiceLauncher(Launcher):
def _handle_signal(self, signo, frame):
# Allow the process to be killed again and die from natural causes
signal.signal(signal.SIGTERM, signal.SIG_DFL)
signal.signal(signal.SIGINT, signal.SIG_DFL)
raise SignalExit(signo)
def wait(self):
signal.signal(signal.SIGTERM, self._handle_signal)
signal.signal(signal.SIGINT, self._handle_signal)
LOG.debug(_('Full set of CONF:'))
CONF.log_opt_values(LOG, std_logging.DEBUG)
status = None
try:
super(ServiceLauncher, self).wait()
except SignalExit as exc:
signame = {signal.SIGTERM: 'SIGTERM',
signal.SIGINT: 'SIGINT'}[exc.signo]
LOG.info(_('Caught %s, exiting'), signame)
status = exc.code
except SystemExit as exc:
status = exc.code
finally:
self.stop()
if rpc:
rpc.cleanup()
return status
class ServiceWrapper(object):
def __init__(self, service, workers):
self.service = service
self.workers = workers
self.children = set()
self.forktimes = []
class ProcessLauncher(object):
def __init__(self):
self.children = {}
self.sigcaught = None
self.running = True
rfd, self.writepipe = os.pipe()
self.readpipe = eventlet.greenio.GreenPipe(rfd, 'r')
signal.signal(signal.SIGTERM, self._handle_signal)
signal.signal(signal.SIGINT, self._handle_signal)
def _handle_signal(self, signo, frame):
self.sigcaught = signo
self.running = False
# Allow the process to be killed again and die from natural causes
signal.signal(signal.SIGTERM, signal.SIG_DFL)
signal.signal(signal.SIGINT, signal.SIG_DFL)
def _pipe_watcher(self):
# This will block until the write end is closed when the parent
# dies unexpectedly
self.readpipe.read()
LOG.info(_('Parent process has died unexpectedly, exiting'))
sys.exit(1)
def _child_process(self, service):
# Setup child signal handlers differently
def _sigterm(*args):
signal.signal(signal.SIGTERM, signal.SIG_DFL)
raise SignalExit(signal.SIGTERM)
signal.signal(signal.SIGTERM, _sigterm)
# Block SIGINT and let the parent send us a SIGTERM
signal.signal(signal.SIGINT, signal.SIG_IGN)
# Reopen the eventlet hub to make sure we don't share an epoll
# fd with parent and/or siblings, which would be bad
eventlet.hubs.use_hub()
# Close write to ensure only parent has it open
os.close(self.writepipe)
# Create greenthread to watch for parent to close pipe
eventlet.spawn(self._pipe_watcher)
# Reseed random number generator
random.seed()
launcher = Launcher()
launcher.run_service(service)
def _start_child(self, wrap):
if len(wrap.forktimes) > wrap.workers:
# Limit ourselves to one process a second (over the period of
# number of workers * 1 second). This will allow workers to
# start up quickly but ensure we don't fork off children that
# die instantly too quickly.
if time.time() - wrap.forktimes[0] < wrap.workers:
LOG.info(_('Forking too fast, sleeping'))
time.sleep(1)
wrap.forktimes.pop(0)
wrap.forktimes.append(time.time())
pid = os.fork()
if pid == 0:
# NOTE(johannes): All exceptions are caught to ensure this
# doesn't fallback into the loop spawning children. It would
# be bad for a child to spawn more children.
status = 0
try:
self._child_process(wrap.service)
except SignalExit as exc:
signame = {signal.SIGTERM: 'SIGTERM',
signal.SIGINT: 'SIGINT'}[exc.signo]
LOG.info(_('Caught %s, exiting'), signame)
status = exc.code
except SystemExit as exc:
status = exc.code
except BaseException:
LOG.exception(_('Unhandled exception'))
status = 2
finally:
wrap.service.stop()
os._exit(status)
LOG.info(_('Started child %d'), pid)
wrap.children.add(pid)
self.children[pid] = wrap
return pid
def launch_service(self, service, workers=1):
wrap = ServiceWrapper(service, workers)
LOG.info(_('Starting %d workers'), wrap.workers)
while self.running and len(wrap.children) < wrap.workers:
self._start_child(wrap)
def _wait_child(self):
try:
pid, status = os.wait()
except OSError as exc:
if exc.errno not in (errno.EINTR, errno.ECHILD):
raise
return None
if os.WIFSIGNALED(status):
sig = os.WTERMSIG(status)
LOG.info(_('Child %(pid)d killed by signal %(sig)d'), locals())
else:
code = os.WEXITSTATUS(status)
LOG.info(_('Child %(pid)d exited with status %(code)d'), locals())
if pid not in self.children:
LOG.warning(_('pid %d not in child list'), pid)
return None
wrap = self.children.pop(pid)
wrap.children.remove(pid)
return wrap
def wait(self):
"""Loop waiting on children to die and respawning as necessary"""
while self.running:
wrap = self._wait_child()
if not wrap:
continue
while self.running and len(wrap.children) < wrap.workers:
self._start_child(wrap)
if self.sigcaught:
signame = {signal.SIGTERM: 'SIGTERM',
signal.SIGINT: 'SIGINT'}[self.sigcaught]
LOG.info(_('Caught %s, stopping children'), signame)
for pid in self.children:
try:
os.kill(pid, signal.SIGTERM)
except OSError as exc:
if exc.errno != errno.ESRCH:
raise
# Wait for children to die
if self.children:
LOG.info(_('Waiting on %d children to exit'), len(self.children))
while self.children:
self._wait_child()
class Service(object):
"""Service object for binaries running on hosts."""
def __init__(self):
self.tg = threadgroup.ThreadGroup('service')
def start(self):
pass
def stop(self):
self.tg.stop()
def wait(self):
self.tg.wait()
def launch(service, workers=None):
if workers:
launcher = ProcessLauncher()
launcher.launch_service(service, workers=workers)
else:
launcher = ServiceLauncher()
launcher.launch_service(service)
return launcher

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# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2012 Red Hat, Inc.
#
# 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.
from eventlet import greenlet
from eventlet import greenpool
from eventlet import greenthread
from ceilometer.openstack.common.gettextutils import _
from ceilometer.openstack.common import log as logging
from ceilometer.openstack.common import loopingcall
LOG = logging.getLogger(__name__)
def _thread_done(gt, *args, **kwargs):
args[0].thread_done(args[1])
class Thread(object):
"""
Wrapper around a greenthread, that holds a reference to
the ThreadGroup. The Thread will notify the ThreadGroup
when it has done so it can be removed from the threads
list.
"""
def __init__(self, name, thread, group):
self.name = name
self.thread = thread
self.thread.link(_thread_done, group, self)
def stop(self):
self.thread.cancel()
def wait(self):
return self.thread.wait()
class ThreadGroup():
"""
The point of this class is to:
- keep track of timers and greenthreads (making it easier to stop them
when need be).
- provide an easy API to add timers.
"""
def __init__(self, name, thread_pool_size=10):
self.name = name
self.pool = greenpool.GreenPool(thread_pool_size)
self.threads = []
self.timers = []
def add_timer(self, interval, callback, initial_delay=None,
*args, **kwargs):
pulse = loopingcall.LoopingCall(callback, *args, **kwargs)
pulse.start(interval=interval,
initial_delay=initial_delay)
self.timers.append(pulse)
def add_thread(self, callback, *args, **kwargs):
gt = self.pool.spawn(callback, *args, **kwargs)
th = Thread(callback.__name__, gt, self)
self.threads.append(th)
def thread_done(self, thread):
try:
thread.wait()
except Exception as ex:
LOG.exception(ex)
finally:
self.threads.remove(thread)
def stop(self):
current = greenthread.getcurrent()
for x in self.threads:
if x is current:
# don't kill the current thread.
continue
try:
x.stop()
except Exception as ex:
LOG.exception(ex)
for x in self.timers:
try:
x.stop()
except Exception as ex:
LOG.exception(ex)
self.timers = []
def wait(self):
for x in self.timers:
try:
x.wait()
except greenlet.GreenletExit:
pass
except Exception as ex:
LOG.exception(ex)
current = greenthread.getcurrent()
for x in self.threads:
if x is current:
continue
try:
x.wait()
except greenlet.GreenletExit:
pass
except Exception as ex:
LOG.exception(ex)

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[DEFAULT]
modules=cfg,iniparser,rpc,importutils,excutils,local,jsonutils,gettextutils,timeutils,notifier,context,log,network_utils,setup,policy
modules=cfg,iniparser,rpc,importutils,excutils,local,jsonutils,gettextutils,timeutils,notifier,context,log,network_utils,setup,policy,service,threadgroup,eventlet_backdoor,loopingcall
base=ceilometer