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Concept

You interact with actors through a *PID. You don’t need to know whether the actor is local (same process) or remote ( another node). The same Tell/Ask APIs work in both cases.

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How it works

  • Local: Message is enqueued directly into the actor’s mailbox.
  • Remote: Message is serialized, sent over TCP, deserialized on the target node, and enqueued there.
The caller uses the same pid.Tell(msg) or pid.Ask(ctx, msg, timeout) regardless of location.

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The Path interface

pid.Path() returns a Path interface: the location-transparent actor identity:
The Path interface
Use Path() for host, port, name, and string representation. QualifiedName() returns the name that identifies the actor within its system, parent/child for a child, which is the name ActorOf, ActorExists, Kill and ReSpawn resolve. Guard for nil when the sender is unknown (e.g., NoSender).

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When location matters

Use pid.IsLocal() or pid.IsRemote() when you need location-specific behavior (e.g., avoiding remote calls for hot paths, or logging).

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ActorOf

ActorOf(ctx, name) returns a *PID whether the actor is local or remote. The framework looks up the actor in the local tree first, then in the cluster registry. You get a unified handle either way. For a top-level actor, name is its name. A child’s name is unique only among its siblings, so two parents can each have a child called worker. A child is found by its qualified name, the names of its ancestors and its own joined by /, from any node: ActorOf(ctx, "orders/worker"). actor.QualifiedName("orders", "worker") builds that name and rejects a name Spawn would reject, and pid.Path().QualifiedName() reports it for a running actor. On the node that hosts it, a child is also found by its bare name; when several children on that node share it, the most recently spawned one is returned. ActorExists, Kill and ReSpawn resolve names the same way.