[CalendarServer-changes] [6427] CalendarServer/trunk/txdav/base/datastore/subpostgres.py

[source_changes at macosforge.org]

Revision: 6427
          http://trac.macosforge.org/projects/calendarserver/changeset/6427
Author:   sagen at apple.com
Date:     2010-10-14 13:15:46 -0700 (Thu, 14 Oct 2010)
Log Message:
-----------
Rather than register another system event trigger for gracefully shutting down, enhance stopService to wait for db initialization to complete.

Modified Paths:
--------------
    CalendarServer/trunk/txdav/base/datastore/subpostgres.py

Modified: CalendarServer/trunk/txdav/base/datastore/subpostgres.py
===================================================================
--- CalendarServer/trunk/txdav/base/datastore/subpostgres.py	2010-10-14 20:11:58 UTC (rev 6426)
+++ CalendarServer/trunk/txdav/base/datastore/subpostgres.py	2010-10-14 20:15:46 UTC (rev 6427)
@@ -245,13 +245,11 @@
         self.resetSchema = resetSchema
 
         # In order to delay a shutdown until database initialization has
-        # completed, we register a before-shutdown callback.  This callback
-        # returns immediately if we're not in the critical code, and returns
-        # a deferred if we are.  That deferred gets fired once database init
-        # is complete and shutdown can proceed.
+        # completed, our stopService( ) examines the delayedShutdown flag.
+        # If True, we wait on the shutdownDeferred to fire before proceeding.
+        # The deferred gets fired once database init is complete.
         self.delayedShutdown = False # set to True when in critical code
         self.shutdownDeferred = None # the actual deferred
-        reactor.addSystemEventTrigger("before", "shutdown", self.shutdownCallback)
 
         # Options from config
         self.databaseName = databaseName
@@ -279,16 +277,6 @@
         self.monitor = None
         self.openConnections = []
 
-    def shutdownCallback(self):
-        """
-        Callback registered for before-reactor-shutdown.  Returns immediately
-        if delayedShutdown is False.  Returns a deferred if delayedShutdown
-        is True.
-        """
-        if self.delayedShutdown:
-            self.shutdownDeferred = Deferred()
-            return self.shutdownDeferred
-
     def activateDelayedShutdown(self):
         """
         Call this when starting database initialization code to protect against
@@ -384,9 +372,10 @@
         connection = self.produceConnection()
         cursor = connection.cursor()
 
-        self.subServiceFactory(self.produceConnection).setServiceParent(self)
+        if self.shutdownDeferred is None:
+            # Only continue startup if we've not begun shutdown
+            self.subServiceFactory(self.produceConnection).setServiceParent(self)
 
-
     def pauseMonitor(self):
         """
         Pause monitoring.  This is a testing hook for when (if) we are
@@ -490,10 +479,16 @@
         """
         Stop all child services, then stop the subprocess, if it's running.
         """
-        d = MultiService.stopService(self)
+
+        if self.delayedShutdown:
+            # We're still in the process of initializing the database, so
+            # delay shutdown until the shutdownDeferred fires.
+            d = self.shutdownDeferred = Deferred()
+            d.addCallback(lambda ignored: MultiService.stopService(self))
+        else:
+            d = MultiService.stopService(self)
+
         def superStopped(result):
-            # Probably want to stop and wait for startup if that hasn't
-            # completed yet...
             monitor = _PostgresMonitor()
             pg_ctl = which("pg_ctl")[0]
             reactor.spawnProcess(monitor, pg_ctl,
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