[CalendarServer-changes] [12900] twext/trunk/twext/application/service.py

[source_changes at macosforge.org]

Revision: 12900
          http://trac.calendarserver.org//changeset/12900
Author:   wsanchez at apple.com
Date:     2014-03-13 15:26:30 -0700 (Thu, 13 Mar 2014)
Log Message:
-----------
Add ReExecService

Added Paths:
-----------
    twext/trunk/twext/application/service.py

Added: twext/trunk/twext/application/service.py
===================================================================
--- twext/trunk/twext/application/service.py	                        (rev 0)
+++ twext/trunk/twext/application/service.py	2014-03-13 22:26:30 UTC (rev 12900)
@@ -0,0 +1,83 @@
+##
+# Copyright (c) 2013-2014 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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