Add the RunShutdowner actor interface

actor.go

@@ -88,3 +88,23 @@ type Resettable interface {
 	// invalid and any process which depends on it should be shut down.
 	Reset(ctx context.Context) error
 }
+
+// RunShutdownable is any object that needs a context in order to shut down.
+// Actors which implement this interface cannot implement the Runnable
+// interface. This can be used to run an http.Server as an actor.
+type RunShutdownable interface {
+	// Run is similar to [Runnable.Run], but takes no context and blocks
+	// until Shutdown has run and exited. It may also return when something
+	// goes wrong and it cannot continue, in which case it must return a
+	// non-nil error explaining why. Shutdown does not need to be called in
+	// the latter case.
+	Run() error
+	// Shutdown shuts down the actor. It must be called while Run is
+	// running, and it must unblock Run even if it fails, the context
+	// expires, it returns an error, etc. Shutdown must return when or
+	// before the context expires, and must return ctx.Err if there is no
+	// other error to be returned. If Shutdown returns any error, the object
+	// must be treated as invalid and any other process which depends on it
+	// should be shut down.
+	Shutdown(ctx context.Context) error
+}