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

Documentation

See

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

Requirements

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

License

aiozmq is offered under the BSD license.

CHANGES

1.0.0 (2022-11-02)

• Support Python 3.9, 3.10, and 3.11 (thanks in part to Esben Sonne)
• Drop support for Python 3.5
• Remove support for using annotations as conversion functions

0.9.0 (2020-01-25)

• Support Python 3.7 and 3.8

0.8.0 (2016-12-07)

• Respect events_backlog parameter in zmq stream creation #86

0.7.1 (2015-09-20)

• Fix monitoring events implementation
• Make the library compatible with Python 3.5

0.7.0 (2015-07-31)

• Implement monitoring ZMQ events #50
• Do deeper lookup for inhereted classes #54
• Relax endpont check #56
• Implement monitoring events for stream api #52

0.6.1 (2015-05-19)

• Dynamically get list of pyzmq socket types

0.6.0 (2015-02-14)

• Process asyncio specific exceptions as builtins.
• Add repr(exception) to rpc server call logs if any
• Add transport.get_write_buffer_limits() method
• Add __repr__ to transport
• Add zmq_type to tr.get_extra_info()
• Add zmq streams

0.5.2 (2014-10-09)

• Poll events after sending zmq message for eventless transport

0.5.1 (2014-09-27)

• Fix loopless transport implementation.

0.5.0 (2014-08-23)

• Support zmq devices in aiozmq.rpc.serve_rpc()
• Add loopless 0MQ transport

0.4.1 (2014-07-03)

• Add exclude_log_exceptions parameter to rpc servers.

0.4.0 (2014-05-28)

• Implement pause_reading/resume_reading methods in ZmqTransport.

0.3.0 (2014-05-17)

• Add limited support for Windows.
• Fix unstable test execution, change ZmqEventLoop to use global shared zmq.Context by default.
• Process cancellation on rpc servers and clients.

0.2.0 (2014-04-18)

• msg in msg_received now is a list, not tuple
• Allow to send empty msg by trsansport.write()
• Add benchmarks
• Derive ServiceClosedError from aiozmq.rpc.Error, not Exception
• Implement logging from remote calls at server side (log_exceptions parameter).
• Optimize byte counting in ZmqTransport.

0.1.3 (2014-04-10)

• Function default values are not passed to an annotaion. Add check for libzmq version (should be >= 3.0)

0.1.2 (2014-04-01)

• Function default values are not passed to an annotaion.

0.1.1 (2014-03-31)

• Rename plural module names to single ones.

0.1.0 (2014-03-30)

• Implement ZmqEventLoop with create_zmq_connection method which operates on zmq transport and protocol.
• Implement ZmqEventLoopPolicy.
• Introduce ZmqTransport and ZmqProtocol.
• Implement zmq.rpc with RPC, PUSHPULL and PUBSUB protocols.