PID - GoAkt

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

Aspect	Description
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

Type	Description
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

Method	Purpose
`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. Local only.
`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.