Python 7.0pl5 Benutzerhandbuch

A further use of the mechanism for identifying a subscribers identity, is so that subscriptions can be
tracked and for processing or interception of data only to be undertaken while there are subscribers in-
terested in the results. This avoids unnecessarily publishing reports when it is known there would be
no one to send them to.

class LogMonitor(netsvc.Service):

def __init__(self):

name = "logmon@%s" % netsvc.processIdentity()

netsvc.Service.__init__(self,name)

self._logger = netsvc.Logger()

self._channels = {}

def notify(self,channel,level,message):

agent = channel[1:-1]

report = {}

report["agent"] = agent

report["level"] = level

report["message"] = message

self.publishReport(agent,report)

def handleSubscription(self,subscription):

agent = subscription.subject()

channel = "(%s)" % agent

if subscription.status() == netsvc.SUBSCRIPTION_REQUESTED:

if len(agent) != 0:

subscriber = subscription.subscriber().agentIdentity()

if not self._channels.has_key(channel):

self._channels[channel] = []

self._logger.monitorChannel(channel,self.notify)

self._channels[channel].append(subscriber)

else:

if self._channels.has_key(channel):

subscriber = subscription.subscriber().agentIdentity()

if subscriber in self._channels[channel]:

index = self._channels[channel].index(subscriber)

del self._channels[channel][index]

if len(self._channels[channel]) == 0:

del self._channels[channel]

self._logger.monitorChannel(channel,None)

logger = netsvc.Logger()

class Publisher(netsvc.Service):

def __init__(self):

netsvc.Service.__init__(self,"publisher")

self._channel = "(%s)" % self.agentIdentity()

def debug(self,message):

logger.notifyChannel(self._channel,netsvc.LOG_DEBUG,message)

In this use of subscription information, the subscription to a specific subject is used to trigger intercep-
tion of messages logged via the logger interface. For the time that subscriptions exist for a particular