Skip to main content
A PID is the sole actor reference in GoAkt. It is a live handle to a running actor: either local (same process) or remote (another node). All messaging goes through a PID.

​
Role

  • Unified reference: One type for local and remote actors. No separate ActorRef.
  • Location-transparent: Use Tell and Ask the same way regardless of location.
  • Identity: Path returns the canonical address. Name, Kind identify the actor.

​
Local vs remote

  • Local PID: Live mailbox, supervision state, full actor-system reference, etc… Created by Spawn.
  • Remote PID: Lightweight handle with address and remoting; messaging via remoting layer. Returned by ActorOf when actor is on another node.
Use pid.IsLocal() or pid.IsRemote() when location matters. pid.ActorSystem() returns nil for remote PIDs: guard before use.

​
Key methods

  • Path: Canonical actor identity (host, port, name, system). Returns Path interface.
  • Name: Actor name within its parent.
  • Kind: Reflected type name of the actor. Empty for remote PIDs.
  • Tell: Fire-and-forget to another PID.
  • Ask: Request-response. Blocks until reply or timeout.
  • IsRunning: Actor is active and processing.
  • IsSuspended: Actor suspended by supervisor.
  • IsStopping: Shutdown in progress.
  • Watch: Receive Terminated when cid stops; cid may live on another node.
  • UnWatch: Stop watching.

​
Obtaining a PID

  • Spawn: system.Spawn(ctx, name, actor) returns a local PID.
  • ActorOf: system.ActorOf(ctx, name) returns local or remote PID.
  • Context: ctx.Self() (current actor), ctx.Sender() (message sender).

​
NoSender

system.NoSender() returns a special PID for messages without a sender (e.g., scheduled messages, external clients). Use it when sending from outside the actor system. NoSender().Path() may be used for wire encoding.