Change events for Nest.js

src/OpenAPM.ts

@@ -2,7 +2,6 @@ import * as os from 'os';
 import http from 'http';
 import ResponseTime from 'response-time';
 import promClient from 'prom-client';
-
 import type {
   Counter,
   CounterConfiguration,
@@ -266,7 +265,7 @@ export class OpenAPM extends LevitateEvents {
       // Skip the OPTIONS requests not to blow up cardinality. Express does not provide
       // information about the route for OPTIONS requests, which makes it very
       // hard to detect correct PATH. Until we fix it properly, the requests are skipped
-      // to not blow up the cardinality. 
+      // to not blow up the cardinality.
       if (!req.route && req.method === 'OPTIONS') {
         return;
       }
@@ -315,7 +314,7 @@ export class OpenAPM extends LevitateEvents {
       }
       if (moduleName === 'nestjs') {
         const { NestFactory } = require('@nestjs/core');
-        instrumentNestFactory(NestFactory, this._REDMiddleware);
+        instrumentNestFactory(NestFactory, this._REDMiddleware, this);
       }
     } catch (error) {
       if (Object.keys(moduleNames).includes(moduleName)) {

src/clients/nestjs.ts

@@ -1,9 +1,13 @@
-import type { NestFactoryStatic } from '@nestjs/core/nest-factory';
+import * as os from 'os';
 import { isWrapped, wrap } from '../shimmer';
+import type { NestFactoryStatic } from '@nestjs/core/nest-factory';
+import type { NestApplication } from '@nestjs/core';
+import type OpenAPM from '../OpenAPM';
 
 export const instrumentNestFactory = (
   nestFactory: NestFactoryStatic,
-  redMiddleware: Function
+  redMiddleware: Function,
+  openapm: OpenAPM
 ) => {
   // Check if the NestFactory is already wrapped
   if (!isWrapped(nestFactory, 'create')) {
@@ -19,9 +23,43 @@ export const instrumentNestFactory = (
           );
           // Add a global RED Middleware to the application
           app.use(redMiddleware);
+
+          wrap(app, 'listen', (ogListen: NestApplication['listen']) => {
+            return function (
+              this: NestApplication['listen'],
+              ...args: Parameters<NestApplication['listen']>
+            ) {
+              openapm.emit('application_started', {
+                timestamp: new Date().toISOString(),
+                event_name: `${openapm.program}_app`,
+                event_state: 'start',
+                entity_type: 'app',
+                workspace: os.hostname(),
+                namespace: openapm.environment,
+                data_source_name: openapm.levitateConfig?.dataSourceName ?? ''
+              });
+              return ogListen.apply(this, args);
+            } as NestApplication['listen'];
+          });
+
           return app;
         };
       }
     );
+
+    const stopEvent = () => {
+      openapm.emit('application_stopped', {
+        timestamp: new Date().toISOString(),
+        event_name: `${openapm.program}_app`,
+        event_state: 'stop',
+        entity_type: 'app',
+        workspace: os.hostname(),
+        namespace: openapm.environment,
+        data_source_name: openapm.levitateConfig?.dataSourceName ?? ''
+      });
+    };
+
+    process.on('SIGINT', stopEvent);
+    process.on('SIGTERM', stopEvent);
   }
 };

src/levitate/events.ts

@@ -42,6 +42,10 @@ export class LevitateEvents extends EventEmitter {
     event: 'application_started',
     ...args: (DomainEventsBody | any)[]
   ): boolean;
+  public emit(
+    event: 'application_stopped',
+    ...args: (DomainEventsBody | any)[]
+  ): boolean;
   public emit(event: any, ...args: any[]): any {
     return super.emit(event, ...args);
   }
@@ -50,6 +54,10 @@ export class LevitateEvents extends EventEmitter {
     event: 'application_started',
     listener: (...args: (DomainEventsBody | any)[]) => void
   ): this;
+  public on(
+    event: 'application_stopped',
+    listener: (...args: (DomainEventsBody | any)[]) => void
+  ): this;
   public on(event: any, listener: (...args: any[]) => void): this {
     return super.on(event, listener);
   }
@@ -58,6 +66,10 @@ export class LevitateEvents extends EventEmitter {
     event: 'application_started',
     listener: (...args: (DomainEventsBody | any)[]) => void
   ): this;
+  public once(
+    event: 'application_stopped',
+    listener: (...args: (DomainEventsBody | any)[]) => void
+  ): this;
   public once(event: any, listener: (...args: any[]) => void): this {
     return super.on(event, listener);
   }