asyncio integration with ZeroMQ

asyncio (PEP 3156) support for ZeroMQ.

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

zmq.asyncio works only by replacement event loop with custom one. This approach works but have two disadvantages:

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

2. It uses internal ZMQ Poller which has fast ZMQ Sockets support but doesn'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 https://github.com/zeromq/pyzmq/issues/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


@asyncio.coroutine
def go():
    server = yield from aiozmq.rpc.serve_rpc(
        ServerHandler(), bind='tcp://127.0.0.1:5555')
    client = yield from aiozmq.rpc.connect_rpc(
        connect='tcp://127.0.0.1:5555')

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

    server.close()
    client.close()

asyncio.get_event_loop().run_until_complete(go())

Low-level request-reply example:

import asyncio
import aiozmq
import zmq

@asyncio.coroutine
def go():
    router = yield from aiozmq.create_zmq_stream(
        zmq.ROUTER,
        bind='tcp://127.0.0.1:*')

    addr = list(router.transport.bindings())[0]
    dealer = yield from 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 = yield from router.read()
        router.write(data)
        answer = yield from dealer.read()
        print(answer)
    dealer.close()
    router.close()

asyncio.get_event_loop().run_until_complete(go())

Comparison to pyzmq

zmq.asyncio provides a asyncio compatible loop implementation.

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

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

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

For details see https://github.com/zeromq/pyzmq/issues/894

Requirements

• Python 3.5+
• pyzmq 13.1+
• optional submodule aiozmq.rpc requires msgpack 0.5+

License

aiozmq is offered under the BSD license.