CODEWITHSUNDEEP
javazeromq
jones321
jones321

Reputation: 85

Dilemma of setting a timeout in ZeroMQ

I currently use ZeroMQ with Java binding. My program is in a PUB/SUB mode. It seems reasonable to set a timeout, while a client can't receive a message from PUB-side.

But for the publish server, who sends messages without a fixed frequency, it's hard to decide a reasonable timeout.

On the other hand, if no timeout is set, then a program would probably stuck at function:

recv()

forever even publish server is dead.

If there a good solution to fix this issue?

Upvotes: 1

Views: 1290

Answers (2)

user3666197
user3666197

Reputation: 1

Yes, there is a good solution or two:

A principally best solution is to use a Poller instance, for which a .poll() method tells your code, again with a help of an explicitly configurable aTimeOut in [ms], whether there is any incoming message to either attempt a non-blocking .recv() method or not even trying to do so, once there is NACK for any such message being present from the call to a .poll() method ( for details check the API ).

Another way is to use a non-blocking mode of a call to the .recv( aSockINST, ZMQ_DONTWAIT ) method. Here, the API + wrapper / binding, specify how it handles a state, where none such message was locally ready to get .recv()-ed, so that one may rely on the common language's available syntax-scaffolding - like { try: except: finally: } or { try: catch: } or { defer; panic(); recover() } - to handle either of the return states from the .recv( .., ZMQ_DONTWAIT ) call. Similar rules apply to an ( almost ) blocking call, with some moderately small .recv() timeout.

Upvotes: 1

Abhijeet Kale
Abhijeet Kale

Reputation: 1716

You can use Pollers:

poller = zmq.Poller()
poller.register(client_receiver, zmq.POLLIN);

for further reading: http://learning-0mq-with-pyzmq.readthedocs.io/en/latest/pyzmq/multisocket/zmqpoller.html

hope it helps.

Upvotes: 1

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