Source code for pykka._ref

from pykka import ActorDeadError, ActorProxy
from pykka._envelope import Envelope
from pykka.messages import _ActorStop

__all__ = ['ActorRef']

[docs]class ActorRef(object): """ Reference to a running actor which may safely be passed around. :class:`ActorRef` instances are returned by :meth:`Actor.start` and the lookup methods in :class:`ActorRegistry <pykka.ActorRegistry>`. You should never need to create :class:`ActorRef` instances yourself. :param actor: the actor to wrap :type actor: :class:`Actor` """ #: The class of the referenced actor. actor_class = None #: See :attr:`Actor.actor_urn`. actor_urn = None #: See :attr:`Actor.actor_inbox`. actor_inbox = None #: See :attr:`Actor.actor_stopped`. actor_stopped = None def __init__(self, actor): self._actor = actor self.actor_class = actor.__class__ self.actor_urn = actor.actor_urn self.actor_inbox = actor.actor_inbox self.actor_stopped = actor.actor_stopped def __repr__(self): return '<ActorRef for {}>'.format(self) def __str__(self): return '{} ({})'.format(self.actor_class.__name__, self.actor_urn)
[docs] def is_alive(self): """ Check if actor is alive. This is based on the actor's stopped flag. The actor is not guaranteed to be alive and responding even though :meth:`is_alive` returns :class:`True`. :return: Returns :class:`True` if actor is alive, :class:`False` otherwise. """ return not self.actor_stopped.is_set()
[docs] def tell(self, message): """ Send message to actor without waiting for any response. Will generally not block, but if the underlying queue is full it will block until a free slot is available. :param message: message to send :type message: picklable dict :raise: :exc:`pykka.ActorDeadError` if actor is not available :return: nothing """ if not self.is_alive(): raise ActorDeadError('{} not found'.format(self)) self.actor_inbox.put(Envelope(message))
[docs] def ask(self, message, block=True, timeout=None): """ Send message to actor and wait for the reply. The message must be a picklable dict. If ``block`` is :class:`False`, it will immediately return a :class:`Future <pykka.Future>` instead of blocking. If ``block`` is :class:`True`, and ``timeout`` is :class:`None`, as default, the method will block until it gets a reply, potentially forever. If ``timeout`` is an integer or float, the method will wait for a reply for ``timeout`` seconds, and then raise :exc:`pykka.Timeout`. :param message: message to send :type message: picklable dict :param block: whether to block while waiting for a reply :type block: boolean :param timeout: seconds to wait before timeout if blocking :type timeout: float or :class:`None` :raise: :exc:`pykka.Timeout` if timeout is reached if blocking :raise: any exception returned by the receiving actor if blocking :return: :class:`pykka.Future`, or response if blocking """ future = self.actor_class._create_future() try: if not self.is_alive(): raise ActorDeadError('{} not found'.format(self)) except ActorDeadError: future.set_exception() else: self.actor_inbox.put(Envelope(message, reply_to=future)) if block: return future.get(timeout=timeout) else: return future
[docs] def stop(self, block=True, timeout=None): """ Send a message to the actor, asking it to stop. Returns :class:`True` if actor is stopped or was being stopped at the time of the call. :class:`False` if actor was already dead. If ``block`` is :class:`False`, it returns a future wrapping the result. Messages sent to the actor before the actor is asked to stop will be processed normally before it stops. Messages sent to the actor after the actor is asked to stop will be replied to with :exc:`pykka.ActorDeadError` after it stops. The actor may not be restarted. ``block`` and ``timeout`` works as for :meth:`ask`. :return: :class:`pykka.Future`, or a boolean result if blocking """ ask_future = self.ask(_ActorStop(), block=False) def _stop_result_converter(timeout): try: ask_future.get(timeout=timeout) return True except ActorDeadError: return False converted_future = ask_future.__class__() converted_future.set_get_hook(_stop_result_converter) if block: return converted_future.get(timeout=timeout) else: return converted_future
[docs] def proxy(self): """ Wraps the :class:`ActorRef` in an :class:`ActorProxy <pykka.ActorProxy>`. Using this method like this:: proxy = AnActor.start().proxy() is analogous to:: proxy = ActorProxy(AnActor.start()) :raise: :exc:`pykka.ActorDeadError` if actor is not available :return: :class:`pykka.ActorProxy` """ return ActorProxy(self)