[Twisted-Python] Modifying the logstring

Einar S. Idsø einar.twisted at norsk-esport.no
Mon Dec 6 05:51:55 EST 2010

I was able to modify the logstring for the TCP query by following a
similar approach to what I did to the UDP logger:

    def logPrefix(self):
        return self.connection.transport.protocol.__class__.__name__ +
", " + str(self.id)

    def startClient(self):
        self.f = self.factory(self, password=self.queryPassword)
        self.connection = reactor.connectTCP(self.ip, self.queryPort, self.f)
        self.connection.transport.logPrefix = self.logPrefix

Perhaps not very elegant, but it does the job and allows me to get a
log prefix which not only tells me the protocol but also the exact

But is it even possibly to do something similar for the UDP scenario
where I have one UDP-logger which calls bound functions from the
individual server-representing instances to do the actual parsing? The
UDP-listener class is defined like this:

class UDPListener(DatagramProtocol):
    _serverList = {}

    def addParser(self, ip, port, f):
        self._serverList[(str(ip), int(port))] = f

    def removeParser(self, ip, port):
        if (str(host), int(port)) in self._serverList:
            del self._serverList[(str(ip), int(port))]

    def datagramReceived(self, data, (host, port)):
        #print "received %r from %s:%d" % (data, host, port)
        if (host, port) in self._serverList:
            self._serverList[(host, port)](data)


On Mon, Dec 6, 2010 at 10:21 AM, Einar S. Idsø
<einar.twisted at norsk-esport.no> wrote:
> Hi,
> I have an application which logs activity on a number of servers by
> two methods:
> 1. TCP-based queries (app is client)
> 2. UDP-based logging (app is server)
> Each server that is being logged is represented by an instance of a
> server class. TCP-queries are performed by each instance at set
> intervals, while the UDP-logs are gathered by a global logging
> instance which listens to a specific port. Events for a given server
> can be triggered by both protocols, but are handled by the server
> instance. In other words: An instance of a server class gathers events
> by polling the server via TCP /and/ by receiving strings from a UDP
> logging instance which passes received datagrams as strings to the
> correct instance.
> Whenever a loggable event results from the TCP queries, the name of
> the protocol class, which is a subclass of
> twisted.internet.protocol.Protocol), is used as the logstring. That is
> fine, as it allows me to distinguish between different server classes,
> although I cannot distinguish between individual servers.
> However, when a loggable event occurs on the UDP logging instance, it
> writes out a longish protocol name which is the same for all the
> different server classes that are subscribing to events on that UDP
> port. I have managed to modify the string by doing the following:
>        self.udpLogger = reactor.listenUDP(myPort, UDPListener())
>        self.udpLogger.logstr = "UDPLogger"
> Yet when the logged string is passed, as a string, to a server
> instance for processing, the logstring for any result remains
> "UDPLogger" no matter how I pass it or what I do to it. I suppose it
> is expected behaviour that the protocol should "follow" a result, no
> matter how it is processed down the line, but is there any way in
> which I can alter the logstring so that instead of "UDPLogger" or the
> name of the protocol class, it instead uses the server id or any other
> value that I specify?
> What I am getting in my logs is:
> 2010-11-30 10:23:09+0100 [CSS,client] Something happened on TCP
> 2010-11-30 10:23:09+0100 [UDPLogger] Something happened on UDP
> What I would like is:
> 2010-11-30 10:23:09+0100 [CSS (TCP),12345] Something happened on TCP
> 2010-11-30 10:23:09+0100 [CSS (UDP),12345] Something happened on UDP
> where 12345 is a unique identifier of the specific server. Or at least:
> 2010-11-30 10:23:09+0100 [CSS,client] Something happened on TCP
> 2010-11-30 10:23:09+0100 [CSS] Something happened on UDP
> so that I know the result from UDP concerns a CSS-server.
> I hope this was possible to understand. Please let me know if anything
> needs to be clarified. :)
> Cheers,
> Einar

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