Support for timeout

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Versions: py-amqplib 0.6.1, RabbitMQ 1.5.4, Python 2.6.4

I would like to perform the following:

  chan.basic_consume(..)
  heartbeat_deadline = new_deadline(...) # Compute a time instant
  while 1:
    next_deadline = max(0, heartbeat_deadline - time.time())
    chan.wait(timeout = next_deadline)
    # We get there if a message was processed,
    # or if nothing was received for the specified amount of time.
    # Check if we reached our deadline:
    if time.time() > heartbeat_deadline:
       chan.basic_publish(...)
       heartbeat_deadline = new_deadline(...)

The purpose is to allow me to run a loop to receive new messages from
a queue synchronously, but that still allow me to send message back to
the server at regular interval (like heartbeat or something like that.)

Could py-ampqlib support that easily? I've not checked sources in detail,
but I think _AbstractTransport._read(self, n) could support an additionnal
parameter 'timeout', which would be used only for receiving the header
of a new frame (other uses would set timeout to None) if .wait() specified
a timeout itself, using select() before the read() operation.

But maybe I misusing the library. Is that another way to obtain the same
behavior? I thought about writing a second process (and thus opening
an additionnal TCP connection) but I'm not really happy with this idea.
I would prefer to perform all the stuff from a single process.

Original issue reported on code.google.com by [email protected] on 21 Jan 2010 at 2:37