Wrap for server close

playground/app.js

@@ -21,6 +21,9 @@ const openapm = new OpenAPM({
 openapm.on('application_started', (domainEvents) => {
   console.log(domainEvents);
 });
+openapm.on('application_stopped', (domainEvents) => {
+  console.log(domainEvents);
+});
 openapm.instrument('express');
 openapm.instrument('mysql');
 

src/clients/express.ts

@@ -1,8 +1,8 @@
-import EventEmitter from 'events';
 import type * as Express from 'express';
 import type { RequestHandler } from 'express';
 import { isWrapped, wrap } from '../shimmer';
 import type OpenAPM from '../OpenAPM';
+import { Server } from 'http';
 
 export const instrumentExpress = (
   express: typeof Express,
@@ -46,7 +46,27 @@ export const instrumentExpress = (
             namespace: '',
             data_source_name: ''
           });
-          return original.apply(this, args);
+          const server = original.apply(this, args) as Server;
+
+          wrap(server, 'close', function (original: Server['close']) {
+            return function (
+              this: Server['close'],
+              ...args: Parameters<Server['close']>
+            ) {
+              openapm.emit('application_stopped', {
+                timestamp: new Date().toISOString(),
+                event_name: 'express_app',
+                event_state: 'stop',
+                entity_type: '',
+                workspace: '',
+                namespace: '',
+                data_source_name: ''
+              });
+              return original.apply(this, args);
+            };
+          });
+
+          return server;
         };
       }
     );