Improve metro device error connection reporting

Summary: Slightly better error handling, as websockets errors propagated without context

Differential Revision: D29515852

fbshipit-source-id: 1df85977965e061a5e4d76bb22a4a3dfb74b6c04

desktop/app/src/dispatcher/metroDevice.tsx

@@ -80,6 +80,7 @@ export default (store: Store, logger: Logger) => {
     }
 
     if (await isMetroRunning()) {
+      try {
         const _ws = new WebSocket(METRO_LOGS_ENDPOINT);
 
         _ws.onopen = () => {
@@ -88,7 +89,13 @@ export default (store: Store, logger: Logger) => {
           registerMetroDevice(ws, store, logger);
         };
 
-      _ws.onclose = _ws.onerror = () => {
+        _ws.onclose = _ws.onerror = function (event?: any) {
+          if (event?.type === 'error') {
+            console.error(
+              `Failed to connect to Metro on ${METRO_LOGS_ENDPOINT}`,
+              event,
+            );
+          }
           if (!unregistered) {
             unregistered = true;
             clearTimeout(guard);
@@ -109,6 +116,9 @@ export default (store: Store, logger: Logger) => {
           registerMetroDevice(undefined, store, logger);
           // Note: no scheduleNext, we won't retry until restart
         }, 5000);
+      } catch (e) {
+        console.error('Error while setting up Metro websocket connect', e);
+      }
     } else {
       scheduleNext();
     }