[zeromq-dev] FW: Help With Regard To the ZMQ Forwarder

Cornelius Toole cornelius.toole at gmail.com
Fri Mar 23 16:35:02 CET 2012


Check out the documentation on devices and pyzmq as well as the zguide

> ... whenever i start a zmq.device(zmq.Forwarder), this blocks my interpreter, so is there any way of starting a forwarder always as a different process or any ways of making it non-blocking.

http://zeromq.github.com/pyzmq/devices.html 
http://zguide.zeromq.org/page:all#Intermediates-and-Devices
-- 
Cornelius Toole
Sent with Sparrow (http://www.sparrowmailapp.com)


On Friday, March 23, 2012 at 12:19 AM, Ronald Swain wrote:

> Hello All, 
> 
> I had one more small question, whenever i start a zmq.device(zmq.Forwarder), this blocks my interpreter, so is there any way of starting a forwarder always as a different process or any ways of making it non-blocking.
> 
> Hope my question is clear.
> 
> Thanks & Regards,
> Ronald
> 
> From: proj_symbian at live.com (mailto:proj_symbian at live.com)
> To: zeromq-dev at lists.zeromq.org (mailto:zeromq-dev at lists.zeromq.org)
> Date: Tue, 20 Mar 2012 12:27:24 +0530
> Subject: Re: [zeromq-dev] FW: Help With Regard To the ZMQ Forwarder
> 
> Ok the first question is i am back to zero, so now when my scripts are working i am able to send messages, the question of cleaning comes.
> 
> i am using the following code for the forwarder and i think thats correct, but when i kill the process which is running the forwarder the SIGTERM signal is not fired i guess and incoming, outgoing and zmq context is not cleaned properly.
> 
> code:
> 
> import zmq
> import signal
> 
> 
> # this method handles the termination of the app
> # this handler is responsible for properly cleaning of the ports
> def termSignalHandler(signum,frame):
>     incoming.close()
>     outgoing.close()
>     context.term()
>     print("termSignal Handler Called")
> 
> def startForwarder():
>     context = zmq.Context(1)
>     incoming = context.socket(zmq.SUB)
>     outgoing = context.socket(zmq.PUB)
> 
>     try:
>         incoming.connect("tcp://127.0.0.1:5559");
>         incoming.setsockopt(zmq.SUBSCRIBE, "")
>     except:
>         print("incoming socket is already open")
> 
>     try:
>         outgoing.bind('tcp://127.0.0.1:4449')
>     except:
>         print("outgoing socket is open")
> 
>     zmq.device(zmq.FORWARDER, incoming, outgoing)
>     
> signal.signal(signal.SIGTERM,termSignalHandler)
> startForwarder()
> 
> a proper copy can be found at https://gist.github.com/2132163, can you guys tell me what wrong i am doing here.
>     
> 
> 
> 
> 
> From: proj_symbian at live.com (mailto:proj_symbian at live.com)
> To: zeromq-dev at lists.zeromq.org (mailto:zeromq-dev at lists.zeromq.org)
> Date: Tue, 20 Mar 2012 11:23:44 +0530
> Subject: Re: [zeromq-dev] FW: Help With Regard To the ZMQ Forwarder
> 
> Hello Cornelius and Justin, 
> 
> I was at last able to get my forwarder to work and it was my mistake.
> 
> My sender code which was like:
> 
> def sendMessage(): context = zmq.Context() sender = context.socket(zmq.PUB) sender.bind('tcp://127.0.0.1:5558') sender.send("This is the sender")
> 
> was the actual problem, i got to know from my reading that call to socket.bind should happen only once, so i changed my sender code to
> something like:
> 
> socket = context.socket(zmq.PUB)
> socket.bind('tcp://127.0.0.1:4443')
> 
> def sendMessage(socket,message):
> try:
> socket.send(message)
> except:
> print "Unable To Send Message"
> 
> and than i was able to send messages but this gets me into two three more problems, i hope you guys will help me out is giving me some
> ideas about this. 
> 
> 
> 
> 
> 
> Date: Mon, 19 Mar 2012 13:18:59 -0500
> From: corntoole at cct.lsu.edu (mailto:corntoole at cct.lsu.edu)
> To: zeromq-dev at lists.zeromq.org (mailto:zeromq-dev at lists.zeromq.org)
> Subject: Re: [zeromq-dev] FW: Help With Regard To the ZMQ Forwarder
> 
> From the looks of your code https://gist.github.com/2119078, you define functions for sending and receiving messages, but you do not call them, like you do with Forwarder.py. 
> 
> Also for the sake of easier testing, you may want to have your sender script to send multiple messages to allow you to see what's going on.-- 
> Cornelius Toole
> Sent with Sparrow (http://www.sparrowmailapp.com)
> 
> 
> On Monday, March 19, 2012 at 11:59 AM, Symbian Projects wrote:
> 
> > Thanks for your reply cornelius.
> > 
> > I am now using netstat for checking the blocked ports.
> > 
> > Meanwhile i have uploaded the code here https://gist.github.com/2119078
> > 
> > and there is no proprietary code at the moment its the basic code where i am trying to get the forwarder working.
> > 
> > and your last point is very valid, i start first the forwarder, than i start the receiver and than the sender to send messages. From this the point you have mentioned can be a problem.
> > 
> > I will be grateful if you can just have a look at the code its very small and let me know if i am doing some wrong.
> > 
> > Regards,
> > Ronald
> > 
> > Date: Mon, 19 Mar 2012 11:24:40 -0500
> > From: cornelius.toole at gmail.com (mailto:cornelius.toole at gmail.com)
> > To: zeromq-dev at lists.zeromq.org (mailto:zeromq-dev at lists.zeromq.org)
> > Subject: Re: [zeromq-dev] FW: Help With Regard To the ZMQ Forwarder
> > 
> > Ronald, 
> > 
> > You can use netstat. You're using windows, right? http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/netstat.mspx?mfr=true
> > 
> > As for debugging your code, can you paste the code into a paste bin or gist.github?
> > Try this for instance: https://gist.github.com/
> > You omit out any code that is proprietary if this for work or research.
> > 
> > After you check your ports, you should think about whether the order in which ports are being opened is an issue. For instance, your forwarder device binds the outgoing port, but what if the  receiver thread starts before the device?
> > 
> > 
> > -- 
> > Cornelius Toole
> > Sent with Sparrow (http://www.sparrowmailapp.com)
> > 
> > 
> > On Monday, March 19, 2012 at 11:11 AM, Symbian Projects wrote:
> > 
> > > Hello Justin,
> > > 
> > > Thanks again for reply. 
> > > 
> > > 
> > > I have tried restarting the platform, and i have also checked it in two different machines, and in both machine it doesn't work.
> > > 
> > > I am clue of ideas how to debug this problem as the no of line of code is very small too. 
> > > 
> > > Is there any way i  can diagnose that the port is closed or blocked something like that.
> > > 
> > > Thanks,
> > > Ronald
> > > 
> > > > From: jhcook at gmail.com (mailto:jhcook at gmail.com)
> > > > Date: Mon, 19 Mar 2012 15:27:12 +0000
> > > > To: zeromq-dev at lists.zeromq.org (mailto:zeromq-dev at lists.zeromq.org)
> > > > Subject: Re: [zeromq-dev] FW: Help With Regard To the ZMQ Forwarder
> > > > 
> > > > If the same code with same libraries no longer works then clearly you
> > > > have a runtime issue. Have you tried restarting the platforms? Maybe
> > > > you should have a look at the order in which things are happening. Are
> > > > you subscribing before the messages are sent?
> > > > 
> > > > Perhaps its an IP filtering issue. Make sure the ports/proto are not blocked.
> > > > 
> > > > On Mon, Mar 19, 2012 at 10:42 AM, Symbian Projects
> > > > <proj_symbian at live.com (mailto:proj_symbian at live.com)> wrote:
> > > > > Hello Justin,
> > > > >
> > > > > Thanks a lot for your reply.
> > > > >
> > > > > Yes i remember for what the thread was started, and that time my forwarder
> > > > > was running great without any problem. I was able to send and receive
> > > > > messages between my publisher and subscribers.
> > > > >
> > > > > Than i added the signals to clean the sockets.
> > > > >
> > > > > After that nothing worked and now even the old code is not working, which
> > > > > was used to work earlier.
> > > > >
> > > > > I will be very grateful if you just have a look at the code i have sent and
> > > > > tell me is there something wrong in that. Please !!
> > > > 
> > > > -- 
> > > > Justin Cook
> > > > _______________________________________________
> > > > zeromq-dev mailing list
> > > > zeromq-dev at lists.zeromq.org (mailto:zeromq-dev at lists.zeromq.org)
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> > > http://lists.zeromq.org/mailman/listinfo/zeromq-dev
> > > 
> > > 
> > > 
> > 
> > 
> > 
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> > 
> 
> 
> 
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