Flush batch logger to not lose info

app.js

@@ -124,20 +124,19 @@ process.on('SIGHUP', function() {
 });
 
 process.on('SIGTERM', function () {
-    global.logger.debug('Signal TERM Received');
-    listener.close();
-    global.logger.debug('Http server closed');
+    listener.close(function () {
+        server.batch.stop(function () {
+            server.batch.drain(function (err) {
+                if (err) {
+                    global.logger.error(err);
+                    return process.exit(1);
+                }
 
-    server.batch.stop();
-    global.logger.debug('Batch queries stopped');
-    server.batch.drain(function (err) {
-        if (err) {
-            global.logger.error(err);
-            return process.exit(1);
-        }
-        global.logger.debug('Batch queries drained');
-        global.logger.info('Exit gracefully');
-        process.exit(0);
+                global.logger.info('Exit gracefully');
+                server.batch.logger.end();
+                process.exit(0);
+            });
+        });
     });
 });
 

app/services/logger.js

@@ -50,6 +50,21 @@ class Logger {
     reopenFileStreams () {
         this.logger.reopenFileStreams();
     }
+
+    // Ensures that the writable stream is flushed.
+    // Use this function before exiting the process to not lose log entries
+    //
+    // See: https://github.com/trentm/node-bunyan/issues/37
+    // See: https://github.com/trentm/node-bunyan/issues/73
+    end () {
+        // process.stdout cannot be closed
+        if (!this.path) {
+            return;
+        }
+
+        this.logger.streams[0].stream.on('finish', resolve);
+        this.logger.streams[0].stream.end(); // close stream, flush buffer to disk
+    }
 }
 
 module.exports = Logger;