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##
# Copyright (c) 2013-2016 Apple Inc. 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.
##
"""
Extensions to L{twisted.application.service}.
"""
__all__ = [
"ReExecService",
]
import sys
import os
import signal
from twisted.application.service import MultiService
from twext.python.log import Logger
class ReExecService(MultiService):
"""
A MultiService which catches SIGHUP and re-exec's the process.
"""
log = Logger()
def __init__(self, pidfilePath, reactor=None):
"""
@param pidFilePath: Absolute path to the pidfile which will need to be
removed
@type pidFilePath: C{str}
"""
self.pidfilePath = pidfilePath
if reactor is None:
from twisted.internet import reactor
self.reactor = reactor
MultiService.__init__(self)
def reExec(self):
"""
Removes pidfile, registers an exec to happen after shutdown, then
stops the reactor.
"""
self.log.warn("SIGHUP received - restarting")
try:
self.log.info("Removing pidfile: {log_source.pidfilePath}")
os.remove(self.pidfilePath)
except OSError:
pass
self.reactor.addSystemEventTrigger(
"after", "shutdown", os.execv,
sys.executable, [sys.executable] + sys.argv
)
self.reactor.stop()
def sighupHandler(self, num, frame):
self.reactor.callFromThread(self.reExec)
def startService(self):
self.previousHandler = signal.signal(signal.SIGHUP, self.sighupHandler)
MultiService.startService(self)
def stopService(self):
signal.signal(signal.SIGHUP, self.previousHandler)
MultiService.stopService(self)
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