Channels: Python 3.4; twisted vs. asyncio in txaio

[mfa]

We migrated from channels 0.8 to 0.9.x (currently on master).
(So maybe I missed sth. that changed from 0.8 to 0.9.x)
Daphne is updated and on master too.
Django 1.9.4
Python 3.4.3

runserver with --noasgi works as expected.
but with asgi every websocket connection results in:

  File "/usr/local/lib/python3.4/dist-packages/twisted/python/log.py", line 101, in callWithLogger
    return callWithContext({"system": lp}, func, *args, **kw)
  File "/usr/local/lib/python3.4/dist-packages/twisted/python/log.py", line 84, in callWithContext
    return context.call({ILogContext: newCtx}, func, *args, **kw)
  File "/usr/local/lib/python3.4/dist-packages/twisted/python/context.py", line 118, in callWithContext
    return self.currentContext().callWithContext(ctx, func, *args, **kw)
  File "/usr/local/lib/python3.4/dist-packages/twisted/python/context.py", line 81, in callWithContext
    return func(*args,**kw)
--- <exception caught here> ---
  File "/usr/local/lib/python3.4/dist-packages/twisted/internet/posixbase.py", line 597, in _doReadOrWrite
    why = selectable.doRead()
  File "/usr/local/lib/python3.4/dist-packages/twisted/internet/tcp.py", line 209, in doRead
    return self._dataReceived(data)
  File "/usr/local/lib/python3.4/dist-packages/twisted/internet/tcp.py", line 215, in _dataReceived
    rval = self.protocol.dataReceived(data)
  File "/usr/local/lib/python3.4/dist-packages/twisted/protocols/basic.py", line 571, in dataReceived
    why = self.lineReceived(line)
  File "/usr/local/lib/python3.4/dist-packages/twisted/web/http.py", line 1720, in lineReceived
    self.allContentReceived()
  File "/usr/local/lib/python3.4/dist-packages/twisted/web/http.py", line 1799, in allContentReceived
    req.requestReceived(command, path, version)
  File "/usr/local/lib/python3.4/dist-packages/twisted/web/http.py", line 832, in requestReceived
    self.process()
  File "/usr/local/lib/python3.4/dist-packages/daphne/http_protocol.py", line 67, in process
    protocol = self.factory.ws_factory.buildProtocol(self.transport.getPeer())
  File "/usr/local/lib/python3.4/dist-packages/twisted/internet/protocol.py", line 135, in buildProtocol
    p = self.protocol()
  File "/usr/local/lib/python3.4/dist-packages/autobahn/websocket/protocol.py", line 665, in __init__
    self.is_closed = txaio.create_future()
  File "/usr/local/lib/python3.4/dist-packages/txaio/_unframework.py", line 43, in _throw_usage_error
    "To use txaio, you must first select a framework "
builtins.RuntimeError: To use txaio, you must first select a framework with .use_twisted() or .use_asyncio()

How can we set use_twisted() or use_asyncio() ?
Daphne seems to require twisted. Why use twisted if there is asyncio (py3.4+)?

[andrewgodwin]

Daphne uses twisted because I'd have to write two separate codebases for asyncio and twisted otherwise so I could support 2.7 as well, which I do plan to do eventually, but it should work just fine for now; I only run on 3.4 when I'm developing channels and I've never seen this.

What version of Twisted and autobahn do you have locally?

[michael-k]

• autobahn: 0.10.9
• Twisted: 15.5.0

We have another project where this exception does not appear. It uses autobahn 0.12.1. I'm checking if upgrading autobahn helps.

[andrewgodwin]

Yeah, I'm on 0.12.1 locally - let me know if that fixes it and I can add an explicit version requirement.

[michael-k]

Works just fine with autobahn 0.12.1.

[andrewgodwin]

Hmm, daphne already depends on autobahn>=0.12 - did you upgrade using pip?

[michael-k]

The project runs in a docker container and all requirements are installed using pip. The requirements.txt had autobahn pinned to 0.10.9.

[andrewgodwin]

Ah, okay, that explains it - I'll close this then, since the package version declarations are accurate.