def run(self):
"""
@summary: This thread is waiting for EVENT_MCX_DATABASE_LOST and if fired, retrying to connect to the databse.
If connection could be established, EVENT_MCX_DATABASE_RECOVERED will be fired.
@note: EVENT_MCX_DATABASE_LOST xor EVENT_MCX_DATABASE_RECOVERED
"""
print "%s waiting for database lose .." % self.getName()
# wait for the database lost event
EVENT_MCX_DATABASE_LOST.wait()
print "%s executing recovery .." % self.getName()
if self.persistent.connected():
self.persistent.disconnect()
# event was fired
# make sure everyone knows the database has not been recovered yet
EVENT_MCX_DATABASE_RECOVERED.clear()
# loop until database is available
while not EVENT_MCX_DATABASE_RECOVERED.isSet():
try:
# connect
self.persistent.connect()
# ping the persistent
if self.persistent.ping():
# on pong database is available
# database is not lost anymore
EVENT_MCX_DATABASE_LOST.clear()
# database connection finally re-established
# fire event, database has been recovered
EVENT_MCX_DATABASE_RECOVERED.set()
print "%s recovered database connection .." % self.getName()
self.persistent.disconnect()
except:
# try until working
pass
# at the end.. "restart" thread
self.run()
def run(self):
"""
@requires: self.isDaemon() == True
@summary: This thread serves forever.
As long as EVENT_MCX_UPDATES_AVAILABLE is not set this thread will look every CONFIG_CHECKUPDATE_INTERVAL seconds for new updates until found.
If updates were found, it will fire EVENT_MCX_UPDATES_AVAILABLE and wait until this event becomes cleared.
"""
# serve forever
while self.isDaemon():
# and event flag not cleared by now
if not EVENT_MCX_UPDATES_AVAILABLE.isSet():
# ensure we do not operate on an invalid object
self.__cursor = None
self.__clearUpdates()
try:
# make sure connection is established
self.persistent.connect()
# check for updates only, if connection is established
if self.persistent.connected():
self.__cursor = self.persistent.getCursor()
# check for updates
self.__checkForUpdates()
# disconnect properly
self.persistent.disconnect()
else:
raise ConnectionException(DATABASE_SERVER_NOT_AVAILABLE)
# no database available
# let's handle the recover thread and wait for it
except ConnectionException, (error):
print "%s fired EVENT_MCX_DATABASE_LOST caused by: %s" % (self.getName(), error)
# handle events
EVENT_MCX_DATABASE_RECOVERED.clear()
EVENT_MCX_DATABASE_LOST.set()
EVENT_MCX_DATABASE_RECOVERED.wait()
# repeat this in a given interval and sleep in the meantime :)
sleep(CONFIG_CHECKUPDATE_INTERVAL)
