Fix and Add Logging for StateMachine websocket close

src/KeepAlive.ts

@@ -57,6 +57,16 @@ export class KeepAlive extends EventEmitter {
    */
   private logger: Logger;
 
+  /**
+   * Flag that indicates whether this object is still monitoring.
+   */
+  public isMonitoring?: Boolean;
+
+  /**
+   * Flag that indicates whether recommend_reconnect event has been emitted and stop() has not been called.
+   */
+  public recommendReconnect?: Boolean;
+
   constructor({
     clientPingTimeout = 6000,
     serverPongTimeout = 4000,
@@ -97,6 +107,7 @@ export class KeepAlive extends EventEmitter {
     }
 
     this.client = client;
+    this.isMonitoring = true;
     this.client.on('outgoing_message', this.setPingTimer, this);
     this.setPingTimer();
   }
@@ -109,6 +120,7 @@ export class KeepAlive extends EventEmitter {
   public stop(): void {
     this.clearPreviousPingTimer();
     this.lastPing = this.client = undefined;
+    this.recommendReconnect = this.isMonitoring = false;
   }
 
   /**
@@ -174,13 +186,13 @@ export class KeepAlive extends EventEmitter {
             if (this.client === undefined) {
               throw errorWithCode(new Error('no client found'), ErrorCode.KeepAliveInconsistentState);
             }
+            // signal that this pong is done being handled
+            this.client.off('slack_event', attemptAcknowledgePong);
 
             // no pong received to acknowledge the last ping within the serverPongTimeout
             this.logger.debug('pong timer expired, recommend reconnect');
+            this.recommendReconnect = true;
             this.emit('recommend_reconnect');
-
-            // signal that this pong is done being handled
-            this.client.off('slack_event', attemptAcknowledgePong);
           }, this.serverPongTimeout);
 
           this.client.on('slack_event', attemptAcknowledgePong, this);

src/RTMClient.ts

@@ -145,6 +145,22 @@ export class RTMClient extends EventEmitter {
             })
             .on('websocket open').transitionTo('handshaking')
           .state('handshaking') // a state in which to wait until the 'server hello' event
+            .on('websocket close')
+              .transitionTo('reconnecting').withCondition(() => this.autoReconnect)
+              .withAction((_from, _to, context) => {
+                this.logger.debug(`reconnecting after unexpected close ${context.eventPayload.reason} 
+                  ${context.eventPayload.code} with isMonitoring set to ${this.keepAlive.isMonitoring} 
+                  and recommendReconnect set to ${this.keepAlive.recommendReconnect}`);
+              })
+              .transitionTo('disconnected')
+              .withAction((_from, _to, context) => {
+                this.logger.debug(`disconnected after unexpected close ${context.eventPayload.reason} 
+                  ${context.eventPayload.code} with isMonitoring set to ${this.keepAlive.isMonitoring} 
+                  and recommendReconnect set to ${this.keepAlive.recommendReconnect}`);
+                // this transition circumvents the 'disconnecting' state (since the websocket is already closed),
+                // so we need to execute its onExit behavior here.
+                this.teardownWebsocket();
+              })
           .global()
             .onStateEnter((state) => {
               this.logger.debug(`transitioning to state: connecting:${state}`);