[zeromq-dev] zmqstream with req socket only sends the first message

[MinRK]

On Tue, Feb 3, 2015 at 7:00 AM, drebs <drebs at riseup.net> wrote:

Thanks a lot for your answer, now it works like a charm.
>
> I couldn't find documentation about this, do you think it's a good idea to
> add
> a paragraph to zmqstream.send docstring (or anywhere else) about threaded
> use?
>
> If you think it's a good idea, I have a suggestion based on the info you
> gave
> me. It's in the patch below, but feel free to modify in the way you think
> it
> is more appropriate.
>
Since this is an issue generic to any use of tornado IOLoop, I would be a
bit more brief, and link to the tornado docs
<http://tornado.readthedocs.org/en/latest/ioloop.html#tornado.ioloop.IOLoop.add_callback>
.

-MinRK


> --
>
> From cf9418dc14b2dc2e1aca5be1b79a105982dcd877 Mon Sep 17 00:00:00 2001
> From: drebs <drebs at riseup.net>
> Date: Tue, 3 Feb 2015 12:50:59 -0200
> Subject: [PATCH] Add doc for threaded zmqstream.send.
>
> ---
>  zmq/eventloop/zmqstream.py |    8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/zmq/eventloop/zmqstream.py b/zmq/eventloop/zmqstream.py
> index 86a97e4..59149ec 100644
> --- a/zmq/eventloop/zmqstream.py
> +++ b/zmq/eventloop/zmqstream.py
> @@ -242,6 +242,14 @@ class ZMQStream(object):
>      def send(self, msg, flags=0, copy=True, track=False, callback=None):
>          """Send a message, optionally also register a new callback for
> sends.
>          See zmq.socket.send for details.
> +
> +        When using threads, calling send on the zmqstream from another
> thread
> +        doesn’t properly tell the IOLoop thread that there’s an event to
> +        process. This could cause small delays if the IOLoop is already
> +        processing lots of events, but it can also cause the message to
> never
> +        be sent if the zmq socket is the only one it’s handling. In this
> case,
> +        you should hand off the stream.send to the IOLoop’s thread via
> +        IOLoop.add_callback.
>          """
>          return self.send_multipart([msg], flags=flags, copy=copy,
> track=track, callback=callback)
>
A


> --
> 1.7.10.4
>
>
>
> --
>
>
> MinRK codificou 9.4K bytes:
> >    Calling send on the zmqstream from another thread doesn’t properly
> tell
> >    the IOLoop thread that there’s an event to process. This could call
> small
> >    delays if the IOLoop is already processing lots of events, but it can
> >    cause the message to never send if the zmq socket is the only one it’s
> >    handling.
> >
> >    You want your ZmqREQConnection.send to hand off the stream.send to the
> >    IOLoop’s thread via IOLoop.add_callback:
> >
> >  def send(self, *args, **kwargs):
> >      print("Sending message to backend: (%s, %s)" % (args, kwargs))
> >      self._ioloop.add_callback(lambda : self._stream.send(*args,
> **kwargs))
> >
> >    -MinRK
> >
> >    On Mon, Feb 2, 2015 at 12:58 PM, drebs [1]drebs at riseup.net wrote:
> >    >
> >
> >      Hello, zmq community.
> >
> >      I’m trying to use a pyzmq’s zmqstream with a REQ socket to talk to a
> >      txzmq REP
> >      socket, but only the first message is ever sent and received back.
> >
> >      REQ pyzmq endpoint code: [2]http://paste.debian.net/143615/
> >      REP txzmq endpoint code: [3]http://paste.debian.net/143617/
> >
> >      I would expect that all the messages would be sent. Am I missing
> >      something
> >      here?
> >
> >      If I let some requests accumulate, and then start the server, all
> the
> >      accumulated requests are replied, but the new ones are not sent.
> >
> >      If I replace the REQ endpoint by a pure pyzmq version with no
> zmqstream
> >      or
> >      ioloop, it works fine ([4]http://paste.debian.net/143619/).
> >
> >      Anyone can give some light on this?
> >
> >      Thanks a lot!
> >      drebs.
> >
> >      —
> >
> >
> --------------------------------------------------------------------------
> >
> >      zeromq-dev mailing list
> >      [5]zeromq-dev at lists.zeromq.org
> >      [6]http://lists.zeromq.org/mailman/listinfo/zeromq-dev
> >
> >    ​
> >
> > References
> >
> >    Visible links
> >    1. http://mailto:drebs@riseup.net/
> >    2. http://paste.debian.net/143615/
> >    3. http://paste.debian.net/143617/
> >    4. http://paste.debian.net/143619/
> >    5. mailto:zeromq-dev at lists.zeromq.org
> >    6. http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>
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