fix(runner): close active requests after onActorStop has finished running

Author: NathanFlurry

engine/sdks/typescript/runner/src/mod.ts

@@ -164,12 +164,19 @@ export class Runner {
 		if (!actor) return;
 
 		// If onActorStop times out, Pegboard will handle this timeout with ACTOR_STOP_THRESHOLD_DURATION_MS
+		//
+		// If we receive a request while onActorStop is running, a Service
+		// Unavailable error will be returned to Guard and the request will be
+		// retried
 		try {
 			await this.#config.onActorStop(actorId, actor.generation);
 		} catch (err) {
 			console.error(`Error in onActorStop for actor ${actorId}:`, err);
 		}
 
+		// Close requests after onActorStop so you can send messages over the tunnel
+		this.#tunnel?.closeActiveRequests(actor);
+
 		this.#sendActorStateUpdate(actorId, actor.generation, "stopped");
 	}
 
@@ -217,6 +224,7 @@ export class Runner {
 		);
 	}
 
+	// IMPORTANT: Make sure to call stopActiveRequests if calling #removeActor
 	#removeActor(
 		actorId: string,
 		generation?: number,
@@ -242,8 +250,6 @@ export class Runner {
 
 		this.#actors.delete(actorId);
 
-		// Unregister actor from tunnel
-		this.#tunnel?.unregisterActor(actor);
 
 		return actor;
 	}

engine/sdks/typescript/runner/src/tunnel.ts

@@ -183,7 +183,7 @@ export class Tunnel {
 		}
 	}
 
-	unregisterActor(actor: ActorInstance) {
+	closeActiveRequests(actor: ActorInstance) {
 		const actorId = actor.actorId;
 
 		// Terminate all requests for this actor
@@ -469,7 +469,12 @@ export class Tunnel {
 				msg: "ignoring websocket for unknown actor",
 				actorId: open.actorId,
 			});
-			// Send close immediately
+
+			// NOTE: Closing a WebSocket before open is equivalent to a Service
+			// Unavailable error and will cause Guard to retry the request
+			//
+			// See
+			// https://github.com/rivet-dev/rivet/blob/222dae87e3efccaffa2b503de40ecf8afd4e31eb/engine/packages/pegboard-gateway/src/lib.rs#L238
 			this.#sendMessage(requestId, {
 				tag: "ToServerWebSocketClose",
 				val: {