acolley / phoenix

Actor framework for Python 3

Description

Phoenix is an actor framework for Python.

It is heavily-inspired by Akka and Elixir.

Example

import asyncio
from phoenix.actor import Actor, Behaviour, Context
from phoenix.system.system import ActorSystem
from typing import Tuple


async def actor_start(context: Context) -> Actor:
    return Actor(state=context, handler=actor_handle)


async def actor_handle(state: Context, msg: str) -> Tuple[Behaviour, Context]:
    print(msg)
    return Behaviour.done, state


async def main():
    system = ActorSystem("system")
    await system.start()
    actor_id = await system.spawn(actor_start)
    await system.cast(actor_id, "Hello there")
    await asyncio.sleep(2)
    await system.shutdown()


asyncio.run(main())

Design

Actors in phoenix are functions that return the actor's state.

Actors are spawned and scheduled using an ActorSystem, which is the runtime upon which actors are executed.

Spawning an actor requires a start function to be supplied that initialises the actor and returns its initial state and the message handler function that will return its next state after receiving a message.

Spawning an actor returns an ActorId that uniquely identifies the actor allowing other actors to send messages to it.

ActorIds can be included in messages so that receiving actors can send messages to other actors dynamically.

Actors can watch other actors in order to be notified when they exit.

An actor can be linked with another actor so that both are stopped when either one exits.