asyncio integration with ZeroMQ

asyncio (PEP 3156) support for ZeroMQ.

The difference between aiozmq and vanilla pyzmq (zmq.asyncio) is:

zmq.asyncio works only by replacing the base event loop with a custom one. This approach works but has two disadvantages:

1. zmq.asyncio.ZMQEventLoop cannot be combined with other loop implementations (most notable is the ultra fast uvloop).

2. It uses the internal ZMQ Poller which has fast ZMQ Sockets support but isn't intended to work fast with many (thousands) regular TCP sockets.

   In practice it means that zmq.asyncio is not recommended to be used with web servers like aiohttp.

   See also zeromq/pyzmq#894

Documentation

See http://aiozmq.readthedocs.org

Simple high-level client-server RPC example:

import asyncio
import aiozmq.rpc


class ServerHandler(aiozmq.rpc.AttrHandler):

    @aiozmq.rpc.method
    def remote_func(self, a:int, b:int) -> int:
        return a + b


async def go():
    server = await aiozmq.rpc.serve_rpc(
        ServerHandler(), bind='tcp://127.0.0.1:5555')
    client = await aiozmq.rpc.connect_rpc(
        connect='tcp://127.0.0.1:5555')

    ret = await client.call.remote_func(1, 2)
    assert 3 == ret

    server.close()
    client.close()

asyncio.run(go())

Low-level request-reply example:

import asyncio
import aiozmq
import zmq

async def go():
    router = await aiozmq.create_zmq_stream(
        zmq.ROUTER,
        bind='tcp://127.0.0.1:*')

    addr = list(router.transport.bindings())[0]
    dealer = await aiozmq.create_zmq_stream(
        zmq.DEALER,
        connect=addr)

    for i in range(10):
        msg = (b'data', b'ask', str(i).encode('utf-8'))
        dealer.write(msg)
        data = await router.read()
        router.write(data)
        answer = await dealer.read()
        print(answer)
    dealer.close()
    router.close()

asyncio.run(go())

Comparison to pyzmq

zmq.asyncio provides an asyncio compatible loop implementation.

But it's based on zmq.Poller which doesn't work well with massive non-zmq socket usage.

E.g. if you build a web server for handling at least thousands of parallel web requests (1000-5000) pyzmq's internal poller will be slow.

aiozmq works with epoll natively, it doesn't need a custom loop implementation and cooperates pretty well with uvloop for example.

For details see zeromq/pyzmq#894

Requirements

• Python 3.6+
• pyzmq 13.1+
• optional submodule aiozmq.rpc requires msgpack 0.5+

License

aiozmq is offered under the BSD license.