[zeromq-dev] Fwd: Problem with IPC

[Oliver Smith]

I also managed to bury this didn't I? :)

- Oliver

-------- Original Message --------
Subject: 	[zeromq-dev] Problem with IPC
Date: 	Mon, 26 Jul 2010 02:05:44 -0500
From: 	Oliver Smith <oliver at kfs.org>
Reply-To: 	0MQ development list <zeromq-dev at lists.zeromq.org>
To: 	0MQ development list <zeromq-dev at lists.zeromq.org>



If an UPSTREAM connects to an IPC socket that has already had data sent,
it will not receive the first message sent after connection:

Given the following upstream:

[lua]
      require 'zmq' ; ctx = zmq.init(1) ; s = ctx:socket(zmq.UPSTREAM) ;
s:connect("ipc:///tmp/zmqdemo")
      s:recv()

[python]
      import zmq ; ctx = zmq.Cotnext() ; s = ctx.socket(zmq.UPSTREAM) ;
s.connect("ipc:///tmp/zmqdemo")
      s.recv()

If you now start a downstream in an interpreter

[lua]
      require 'zmq' ; ctx = zmq.init(1) ; s = ctx:socket(zmq.DOWNSTREAM)
; s:bind("ipc:///tmp/zmqdemo")
      s:send("Hello")
      -- restart the upstream
      s:send("blah")
      -- wait a few moments
      s:send("World")

[python]
      import zmq ; ctx = zmq.Context() ; s = ctx.socket(zmq.DOWNSTREAM) ;
s.bind("ipc:///tmp/zmqdemo")
      s.send("Hello")
      -- restart the upstream
      s.send("blah")
      -- wait a few moments
      s.send("World")


The second upstream won't see the "blah" message but it will see the
"World" message.

Note: the "blah" is only being sent /after/ the first upstream has
closed and the second upstream has connected.

Even adding an explicit s:close() / s.close() does not fix this.

- Oliver


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.zeromq.org/pipermail/zeromq-dev/attachments/20100728/32ca3ff2/attachment.htm>