Proxy to self as attribute on actor causes deadlock

[nmccready]

Your documentation says that referencing your internal proxy is ideal. This is exactly what I want to do, but it hangs every time. It gets out of the constructor and does nothing. Is this a race condition on proxy (internal vs external)?

Details:

• code below
• Python 2.7.8

#! /usr/bin/env python
from pykka import ThreadingFuture, ThreadingActor


def go_command():
    actor = HungActor.start()
    proxy = actor.proxy()
    proxy.run()
    actor.stop()


class HungActor(ThreadingActor):
    def __init__(self):
        super(HungActor, self).__init__()
        proxy = self.actor_ref.proxy()
        print proxy
        self.proxy = proxy
        print "out of constructor"

    def run(self):
        print "run"
        self.proxy.a()

    def a(self):
        print "a async"
        self.proxy.b()

    def b(self):
        print "b async"


if __name__ == '__main__':
    # scriptine allows for quick easy scripting
    # where this script will run via `corelogic_data.py command`
    # commands are any def with {SOME_NAME}_command
    import scriptine

    scriptine.run()

to run:
./crap_actor.py go

[nmccready]

Here is the same actor but using message passing. This is working.

#! /usr/bin/env python
from pykka import ThreadingFuture, ThreadingActor


def go_command():
    actor = NotHungActor.start()
    proxy = actor.proxy()
    proxy.a()
    # actor.stop()


class NotHungActor(ThreadingActor):
    def __init__(self):
        super(NotHungActor, self).__init__()
        proxy = self.actor_ref.proxy()
        # print proxy
        # self.proxy = proxy
        # print "out of constructor"

    def on_receive(self, message):
        return {
            'run': self.run,
            'a': self.a,
            'b': self.b,
        }[message["msg"]]()

    def run(self):
        print "run"
        self.actor_ref.tell({"msg": "a"})

    def a(self):
        print "a async"
        self.actor_ref.tell({"msg": "b"})

    def b(self):
        print "b async"


if __name__ == '__main__':
    # scriptine allows for quick easy scripting
    # where this script will run via `corelogic_data.py command`
    # commands are any def with {SOME_NAME}_command
    import scriptine

    scriptine.run()

[jodal]

I can't immediately see the source of the problem here. I'll have to experiment a bit with this myself.

[sergunich]

I've had similar issue.
In my case problem was in recursive introspection of proxy attribute when I tried to access it.
https://www.pykka.org/en/latest/#actor-proxies
https://www.pykka.org/en/latest/#traversable-attributes-on-proxies

Instead:

# proxy as attr
self.proxy = self.actor_ref.proxy()

#later in code
self.proxy.attr_or_method() #there starts recursive introspection

try to use this:

#method that return proxy
def proxy(self):
    return self.actor_ref.proxy()

#later in code
self.proxy().attr_or_method() #no recursice introspection