Flush logger before exiting process (#10905)

* Wait for async logs

* Fix tests

* Better solution

Based on https://stackoverflow.com/a/59260151

* Fix lint/test coverage

Co-authored-by: Koen Kanters <koenkanters94@gmail.com>

lib/controller.ts

@@ -104,7 +104,7 @@ class Controller {
             logger.error('Check https://www.zigbee2mqtt.io/guide/installation/20_zigbee2mqtt-fails-to-start.html for possible solutions'); /* eslint-disable-line max-len */
             logger.error('Exiting...');
             logger.error(error.stack);
-            this.exitCallback(1);
+            await this.exit(1);
         }
 
         // Disable some legacy options on new network creation
@@ -145,7 +145,7 @@ class Controller {
             logger.error(`MQTT failed to connect: ${error.message}`);
             logger.error('Exiting...');
             await this.zigbee.stop();
-            this.exitCallback(1);
+            await this.exit(1);
         }
 
         // Call extensions
@@ -197,13 +197,18 @@ class Controller {
         try {
             await this.zigbee.stop();
             logger.info('Stopped Zigbee2MQTT');
-            this.exitCallback(0);
+            await this.exit(0);
         } catch (error) {
             logger.error('Failed to stop Zigbee2MQTT');
-            this.exitCallback(1);
+            await this.exit(1);
         }
     }
 
+    async exit(code: number): Promise<void> {
+        await logger.end();
+        this.exitCallback(code);
+    }
+
     @bind async onZigbeeAdapterDisconnected(): Promise<void> {
         logger.error('Adapter disconnected, stopping');
         await this.stop();

lib/util/logger.ts

@@ -91,8 +91,10 @@ if (settings.get().advanced.log_rotation) {
     transportFileOptions.maxsize = 10000000; // 10MB
 }
 
+let fileTransport : winston.transport;
 if (output.includes('file')) {
-    transportsToUse.push(new winston.transports.File(transportFileOptions));
+    fileTransport = new winston.transports.File(transportFileOptions);
+    transportsToUse.push(fileTransport);
 }
 
 /* istanbul ignore next */
@@ -181,6 +183,28 @@ function error(message: string): void {
     logger.error(message);
 }
 
+// Workaround for https://github.com/winstonjs/winston/issues/1629.
+// https://github.com/Koenkk/zigbee2mqtt/pull/10905
+/* istanbul ignore next */
+async function end(): Promise<void> {
+    logger.end();
+
+    await new Promise<void>((resolve) => {
+        if (!fileTransport) {
+            process.nextTick(resolve);
+        } else {
+            // @ts-ignore
+            if (fileTransport._dest) {
+                // @ts-ignore
+                fileTransport._dest.on('finish', resolve);
+            } else {
+                // @ts-ignore
+                fileTransport.on('open', () => fileTransport._dest.on('finish', resolve));
+            }
+        }
+    });
+}
+
 export default {
-    logOutput, warn, warning, error, info, debug, setLevel, getLevel, cleanup, addTransport, winston: logger,
+    logOutput, warn, warning, error, info, debug, setLevel, getLevel, cleanup, addTransport, end, winston: logger,
 };

test/stub/logger.js

@@ -23,6 +23,7 @@ const mock = {
     setLevel: (newLevel) => {level = newLevel},
     getLevel: () => level,
     setTransportsEnabled: (value) => {transportsEnabled = value},
+    end: jest.fn(),
 };
 
 jest.mock('../../lib/util/logger', () => (mock));