Sent from my LG phone twisted-python-requ...@twistedmatrix.com wrote:
>Send Twisted-Python mailing list submissions to > twisted-python@twistedmatrix.com > >To subscribe or unsubscribe via the World Wide Web, visit > http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python >or, via email, send a message with subject or body 'help' to > twisted-python-requ...@twistedmatrix.com > >You can reach the person managing the list at > twisted-python-ow...@twistedmatrix.com > >When replying, please edit your Subject line so it is more specific >than "Re: Contents of Twisted-Python digest..." > > >Today's Topics: > > 1. Re: client connecting to 2 servers (nonsimultaneously) > (benjamin.bertr...@lfv.se) > 2. Re: client connecting to 2 servers (nonsimultaneously) > (Jason Rennie) > 3. Re: client connecting to 2 servers (nonsimultaneously) > (exar...@twistedmatrix.com) > 4. Re: client connecting to 2 servers (nonsimultaneously) > (Jason Rennie) > 5. Re: client connecting to 2 servers (nonsimultaneously) > (Glyph Lefkowitz) > > >---------------------------------------------------------------------- > >Message: 1 >Date: Wed, 12 Jan 2011 09:49:34 +0000 >From: <benjamin.bertr...@lfv.se> >Subject: Re: [Twisted-Python] client connecting to 2 servers > (nonsimultaneously) >To: <twisted-python@twistedmatrix.com> >Message-ID: <2c9a58914594e34aa28179db776fabdf9...@xw-exch04.lfv.se> >Content-Type: text/plain; charset="iso-8859-1" > >One small question about the following code: >Why did you use reactor.callWhenRunning in the __init__ method? >Why not calling directly reactor.connectTCP? > >Cheers, > >Benjamin > >Fr?n: twisted-python-boun...@twistedmatrix.com >[mailto:twisted-python-boun...@twistedmatrix.com] F?r Jason Rennie >Skickat: den 11 januari 2011 14:11 >Till: Twisted general discussion >?mne: Re: [Twisted-Python] client connecting to 2 servers (nonsimultaneously) > >You could probably generalize and simplify by using a collections.deque of >hosts/ports and using the rotate() method before each?reactor.connectTCP. >?Also, no need for multiple reactor imports---one at the top of the code is >fine. ?Note that if the connection is "lost" in a non-clean fashion, you may >also want to reconnect. ?IIUC, "fail" only handles the case that no connection >is made (protocol is never created). > >import collections >from twisted.internet import reactor > >class MyClientFactory(object): >?? ?protocol = MyClientProtocol >?? ?def __init__(self, hosts): >?? ? ? ?self.hosts = collections.deque(hosts) >?? ? ? ?reactor.callWhenRunning(reactor.connectTCP, self.hosts[0][0], >self.hosts[0][1], self) >?? ? ? ?self.hosts.rotate(1) >?? ?def clientConnectionFailed(self, connector, reason): >?? ? ? ?reactor.callLater(2.0, connectTCP, self.hosts[0][0], self.hosts[0][1], >self) >?? ? ? ?self.hosts.rotate(1) > >factory = MyClientFactory([('host1', port1), ('host2', port2), ...]) >reactor.run() > >Cheers, > >Jason > >On Tue, Jan 11, 2011 at 5:17 AM, <benjamin.bertr...@lfv.se> wrote: >Hi, > >I'm new to twisted and I have started to write a new protocol with a TCP >client and server. >In my protocol, a client should be able to connect to 2 servers >(master/slave node - only the master accepts connection). >The client should try to connect to server1. If it fails, try to connect >to server2 (after a specific timeout). If that fails, try server1... >I came up with a solution (see below). >As I'm new to twisted and I haven't seen anything like that in the >examples, I'd like to check if that's a proper way to do it. >Any comments is welcome. > >Thanks > >Benjamin > >*********************************************** >class MyClientFactory(ClientFactory): > >? ?protocol = MyClientProtocol > >? ?def __init__(self, host2=None): >? ? ? ?self.host1 = None >? ? ? ?self.host2 = host2 > >? ?def clientConnectionFailed(self, connector, reason): >? ? ? ?from twisted.internet import reactor >? ? ? ?if self.host2 is None: >? ? ? ? ? ?# host2 is not defined, reconnect to host1 >? ? ? ? ? ?reactor.callLater(2.0, connector.connect) >? ? ? ?else: >? ? ? ? ? ?destination = connector.getDestination() >? ? ? ? ? ?if self.host1 is None: >? ? ? ? ? ? ? ?# First connection failed, initialize host1, and try >host2 >? ? ? ? ? ? ? ?self.host1 = destination.host >? ? ? ? ? ? ? ?host = self.host2 >? ? ? ? ? ?elif destination.host == self.host1: >? ? ? ? ? ? ? ?# Connection to host1 failed, try host2 >? ? ? ? ? ? ? ?host = self.host2 >? ? ? ? ? ?else: >? ? ? ? ? ? ? ?# Connection to host2 failed, try host1 >? ? ? ? ? ? ? ?host = self.host1 >? ? ? ? ? ?reactor.callLater(2.0, reactor.connectTCP, host, >destination.port, self) > > >factory = MyClientFactory(server2) >from twisted.internet import reactor >reactor.connectTCP(server1, 8010, factory) >reactor.run() >*********************************************** > > >_______________________________________________ >Twisted-Python mailing list >Twisted-Python@twistedmatrix.com >http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python > > > >-- >Jason Rennie >Research Scientist, ITA Software >617-714-2645 >http://www.itasoftware.com/ > > > >------------------------------ > >Message: 2 >Date: Wed, 12 Jan 2011 10:15:59 -0500 >From: Jason Rennie <jren...@gmail.com> >Subject: Re: [Twisted-Python] client connecting to 2 servers > (nonsimultaneously) >To: Twisted general discussion <twisted-python@twistedmatrix.com> >Message-ID: > <AANLkTi=ge7JGPY3_woNu6LCapUEXjH88pRZ=tb05g...@mail.gmail.com> >Content-Type: text/plain; charset="iso-8859-1" > >Habit, mostly. I think it's a good habit, though. The reason is that I >wanted to make sure the __init__ code completed before the connectTCP was >called. In this case, it doesn't matter, but if I had a number of things I >wanted to do in __init__, it might matter. Consider: > >class MyClientProtocol(Protocol): > def connectionMade(self): > self.factory.numConnections += 1 > >class MyClientFactory(Factory): > def __init__(self): > reactor.connectTCP(host, port, self) > self.numConnections = 0 > >'course, I'm sure you'd put reactor.connectTCP *after* the numConnections >initializer, but using callWhenRunning ensures that the order doesn't >matter, so it's one less thing you have to worry about :-) > >Jason > >On Wed, Jan 12, 2011 at 4:49 AM, <benjamin.bertr...@lfv.se> wrote: > >> One small question about the following code: >> Why did you use reactor.callWhenRunning in the __init__ method? >> Why not calling directly reactor.connectTCP? >> >> Cheers, >> >> Benjamin >> >> >-- >Jason Rennie >Research Scientist, ITA Software >617-714-2645 >http://www.itasoftware.com/ >-------------- next part -------------- >An HTML attachment was scrubbed... >URL: >http://twistedmatrix.com/pipermail/twisted-python/attachments/20110112/74ab6e3d/attachment.html > > >------------------------------ > >Message: 3 >Date: Wed, 12 Jan 2011 15:26:37 -0000 >From: exar...@twistedmatrix.com >Subject: Re: [Twisted-Python] client connecting to 2 servers > (nonsimultaneously) >To: Twisted general discussion <twisted-python@twistedmatrix.com> >Message-ID: > > <20110112152637.1811.1981888275.divmod.xquotient.9@localhost.localdomain> > >Content-Type: text/plain; charset="utf-8"; format="flowed" > >On 03:15 pm, jren...@gmail.com wrote: >>Habit, mostly. I think it's a good habit, though. The reason is that >>I >>wanted to make sure the __init__ code completed before the connectTCP >>was >>called. In this case, it doesn't matter, but if I had a number of >>things I >>wanted to do in __init__, it might matter. Consider: >> >>class MyClientProtocol(Protocol): >> def connectionMade(self): >> self.factory.numConnections += 1 >> >>class MyClientFactory(Factory): >> def __init__(self): >> reactor.connectTCP(host, port, self) >> self.numConnections = 0 >> >>'course, I'm sure you'd put reactor.connectTCP *after* the >>numConnections >>initializer, but using callWhenRunning ensures that the order doesn't >>matter, so it's one less thing you have to worry about :-) > >Although note that if the reactor is already running when you >instantiate the factory, then callWhenRunning will immediately call the >function you pass to it, as demonstrated by this transcript in which the >reactor is already running: > > >>> def foo(): > ... print 'foo running' > ... >>> from twisted.internet import reactor > >>> reactor.callWhenRunning(foo) > foo running > >>> >Jean-Paul > > > >------------------------------ > >Message: 4 >Date: Wed, 12 Jan 2011 10:52:05 -0500 >From: Jason Rennie <jren...@gmail.com> >Subject: Re: [Twisted-Python] client connecting to 2 servers > (nonsimultaneously) >To: Twisted general discussion <twisted-python@twistedmatrix.com> >Message-ID: > <AANLkTimRg4xWrjwPQLwqVUabOAtJLwJ=quvlyavys...@mail.gmail.com> >Content-Type: text/plain; charset="iso-8859-1" > >Benjamin, sorry for providing you with an incorrect explanation. Jean-Paul, >thank you for correcting my broken understanding of callWhenRunning. > >Is there a call which puts a function into the reactor's queue of tasks to >be completed? > >Thanks, > >Jason > >On Wed, Jan 12, 2011 at 10:26 AM, <exar...@twistedmatrix.com> wrote: > >> Although note that if the reactor is already running when you >> instantiate the factory, then callWhenRunning will immediately call the >> function you pass to it, as demonstrated by this transcript in which the >> reactor is already running: >> >> >>> def foo(): >> ... print 'foo running' >> ... >>> from twisted.internet import reactor >> >>> reactor.callWhenRunning(foo) >> foo running >> >>> >> Jean-Paul >> >> >-- >Jason Rennie >Research Scientist, ITA Software >617-714-2645 >http://www.itasoftware.com/ >-------------- next part -------------- >An HTML attachment was scrubbed... >URL: >http://twistedmatrix.com/pipermail/twisted-python/attachments/20110112/45f97e25/attachment-0001.htm > > >------------------------------ > >Message: 5 >Date: Wed, 12 Jan 2011 11:32:55 -0500 >From: Glyph Lefkowitz <gl...@twistedmatrix.com> >Subject: Re: [Twisted-Python] client connecting to 2 servers > (nonsimultaneously) >To: Twisted general discussion <twisted-python@twistedmatrix.com> >Message-ID: > <aanlktinoenjnltgbsj5bl1zm2cwc8n5kk18+73tit...@mail.gmail.com> >Content-Type: text/plain; charset="utf-8" > >On Wed, Jan 12, 2011 at 10:52 AM, Jason Rennie <jren...@gmail.com> wrote: > >> Benjamin, sorry for providing you with an incorrect explanation. >> Jean-Paul, thank you for correcting my broken understanding of >> callWhenRunning. >> >> Is there a call which puts a function into the reactor's queue of tasks to >> be completed? >> > >The reactor doesn't have a queue of tasks to be completed. It has sets of >various event sources, which it executes in no particular order. > >Scheduling a timed event with callLater(0,...) might do what you want, >though. >-------------- next part -------------- >An HTML attachment was scrubbed... >URL: >http://twistedmatrix.com/pipermail/twisted-python/attachments/20110112/5d2959bd/attachment-0001.htm > > >------------------------------ > >_______________________________________________ >Twisted-Python mailing list >Twisted-Python@twistedmatrix.com >http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python > > >End of Twisted-Python Digest, Vol 82, Issue 12 >********************************************** _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
