CODEWITHSUNDEEP
pythonmultithreadingeventstwistedreactor
Mike Trpcic
Mike Trpcic

Reputation: 25669

Multiple reactors (main loops) in one application through threading (or alternative means)

I've got an idea for an app I'd like to work on to learn a bit more about Twisted and WebSockets. I was thinking of integrating a previously written IRC Bot into a web application. As far as I can see it, I would need three reactors to make it work:

In my mind, this makes sense. It seems like it would be possible. Does anyone have any examples of multiple reactors running in separate threads, or is this something I've imagined that can't be done in the current incarnation of Twisted.

Are there any architecture changes that can (or should) be made to minimize the reactor count, etc?

Thanks for any help.

Upvotes: 19

Views: 9228

Answers (2)

Glyph
Glyph

Reputation: 31910

Lucky for you, it is easy to reduce the number of reactors, specifically, to 1:

You can only ever have a single reactor, in a single thread, in any given Twisted process. If you try to have more, nothing will work.

The whole point of a reactor, actually, is to facilitate having multiple sources of events combined into a single thread. If you want to listen on 3 different ports with 3 different protocols, your application might look like this:

from twisted.internet import reactor
reactor.listenTCP(4321, FirstProtocolFactory())
reactor.listenTCP(5432, SecondProtocolFactory())
reactor.listenTCP(6543, ThirdProtocolFactory())
reactor.run()

Of course, you may not actually be calling listenTCP directly yourself, as you probably want to use Service objects from twisted.application.internet if you are using twistd, either via a .tac file or a twistd plugin. And you won't need to call reactor.run() yourself, if twistd is doing it for you. My point here is that, via whatever means, you load up the reactor with all the events you expect it to react to - listening servers, client connections, timed events - and it will react to each one as it occurs. (Hence, "reactor".)

For the specific values of what FirstProtocolFactory, SecondProtocolFactory, and ThirdProtocolFactory should be, see the links in pyfunc's answer.

Upvotes: 20

pyfunc
pyfunc

Reputation: 66739

No, I don't think you need multiple reactors.

What you need, is a multi-service multi-protocol application. This is where Twisted really shines.

So your application should start a web service, IRC Bot service and WebSocket server.

Use twisted application service framework, specially starting a multi service

Check out the IRC bot implementation and twisted IRC protocol support:

and for websocket and twisted

Upvotes: 5

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