Report unhandled rejections and exceptions to the host process

packages/apps-engine/deno-runtime/error-handlers.ts

@@ -0,0 +1,33 @@
+import * as Messenger from './lib/messenger.ts';
+
+export function unhandledRejectionListener(event: PromiseRejectionEvent) {
+    event.preventDefault();
+
+    const { type, reason } = event;
+
+    Messenger.sendNotification({
+        method: 'unhandledRejection',
+        params: [
+            {
+                type,
+                reason: reason instanceof Error ? reason.message : reason,
+                timestamp: new Date(),
+            },
+        ],
+    });
+}
+
+export function unhandledExceptionListener(event: ErrorEvent) {
+    event.preventDefault();
+
+    const { type, message, filename, lineno, colno } = event;
+    Messenger.sendNotification({
+        method: 'unhandledException',
+        params: [{ type, message, filename, lineno, colno }],
+    });
+}
+
+export default function registerErrorListeners() {
+    addEventListener('unhandledrejection', unhandledRejectionListener);
+    addEventListener('error', unhandledExceptionListener);
+}

packages/apps-engine/deno-runtime/main.ts

@@ -21,6 +21,7 @@ import videoConferenceHandler from './handlers/videoconference-handler.ts';
 import apiHandler from './handlers/api-handler.ts';
 import handleApp from './handlers/app/handler.ts';
 import handleScheduler from './handlers/scheduler-handler.ts';
+import registerErrorListeners from './error-handlers.ts';
 
 type Handlers = {
     app: typeof handleApp;
@@ -126,4 +127,6 @@ async function main() {
     }
 }
 
+registerErrorListeners();
+
 main();

packages/apps-engine/src/server/runtime/deno/AppsEngineDenoRuntime.ts

@@ -367,7 +367,7 @@ export class DenoRuntimeSubprocessController extends EventEmitter {
         this.deno.stderr.on('data', this.parseError.bind(this));
         this.deno.on('error', (err) => {
             this.state = 'invalid';
-            console.error('Failed to startup Deno subprocess', err);
+            console.error(`Failed to startup Deno subprocess for app ${this.getAppId()}`, err);
         });
         this.once('ready', this.onReady.bind(this));
         this.parseStdout(this.deno.stdout);
@@ -544,6 +544,10 @@ export class DenoRuntimeSubprocessController extends EventEmitter {
             case 'log':
                 console.log('SUBPROCESS LOG', message);
                 break;
+            case 'unhandledRejection':
+            case 'unhandledException':
+                this.debug('Unhandled error of type "%s" caught in subprocess', method);
+                break;
             default:
                 console.warn('Unrecognized method from sub process');
                 break;