Pyzmq: DISH / RADIO support ?

[stuaxo]

Hi,
Thanks for pyzmq :)

Is DISH/RADIO support available / coming in pyzmq ?

On Ubuntu Xenial 64 bit, I compiled my own zeromq with --prefix=/usr/local. I then install pyzmq with --zmq=/usr/local but RADIO + DISH didn't seem to be available -

AttributeError: module 'zmq' has no attribute 'DISH'

Cheers
S

[minrk]

These features are unreleased drafts at this point. Did you configure your libzmq with --enable-drafts set? Draft features are disabled by default in current master of libzmq. Since the draft mechanism is _itself_ also an unreleased spec subject to change, only pyzmq >= 15.4 even tries to support it. pyzmq should detect the draft API if it was enabled (zmq.DRAFT_API), then zmq.DISH should be defined. The additional draft _methods_ associated with those sockets are not exposed yet, however.

If DISH is not defined, you can create a dish socket with

zmq.RADIO = 14
zmq.DISH = 15

since socket types are just constants, after all.

I've had bad experiences every time I try to support unreleased features from libzmq in pyzmq, so I'm planning to wait until closer to release (perhaps after the first beta) before adding these things.

[stuaxo]

Cheers this all makes lots of sense, I'll stick to non draft features for now :)

[sublee]

Now libzmq enables the draft API by default. Is it a good time to support the draft API in PyZMQ? Such as zmq.RADIO, zmq.DISH, or zmq.Socket.join.

[sublee]

@minrk Would you reopen this issue please?

[sublee]

Thank you!

Now we need some Pythonic API for zmq_join, zmq_leave, or zmq_msg_set_routing_id.

[minrk]

Yup, you can create RADIO/DISH sockets just fine now, but since zmq_msg_set_group and zmq_join|leave are not yet wrapped, they aren't useful.

Frankly, it seems that PUB/SUB do the same thing as RADIO/DISH, only better, since they support multi-frame messages, etc. So I would encourage anyone interested in RADIO/DISH to use PUB/SUB instead, as PUB/SUB is strictly more capable. Same for ROUTER/DEALER vs CLIENT/SERVER, it would seem.

[sublee]

I agree to you. For now, yes, we must use PUB-SUB or ROUTER-DEALER instead of RADIO-DISH or CLIENT-SERVER. There's even no way to make a proxy for the draft patterns.

But as you know, I'm having a multi-threading safety issue when using PUB-SUB in PyZMQ with gevent. So I am interested in the draft patterns especially RADIO-DISH.

[ubald]

The advantage of RADIO/DISH over PUB/SUB in my opinion is more about being able to use UDP.

[Greendogo]

Yes, PUB-SUB cannot do UDP, which makes the statement regarding PUB-SUB being strictly more capable than RADIO-DISH absolutely false. I need fast video frame transfer and UDP is the primary choice for that, so PUB-SUB is actually nigh useless for my purposes comparatively.

[busimus]

And RADIO-DISH does exact matching on groups, as opposed to prefix matching of PUB-SUB topics. For that reason PUB-SUB is nigh useless for me as well, so I really hope RADIO-DISH becomes stable faster.

[minrk]

I'll work on supporting the draft sockets. You will need to make sure to compile pyzmq and libzmq yourself (avoid public wheels) because pyzmq binaries won't enable unstable draft APIs.

[minrk]

Assuming you have libzmq already built with draft support, you should be able to give this a try with:

pip install --pre pyzmq --install-option=--enable-drafts [-install-option=--zmq=/path/to/zmq/prefix]

and try one of the examples here

[Bklyn]

Works for me. Thanks!

[stuaxo]

I'm no longer working on the project where I was going to use this, but thanks for getting it working, I'm sure to in future.

[agn-7]

Eventually is available the RADIO/DISH pattern in pyzmq?

Is there any example?