Create LevitateEvents class

playground/app.js

@@ -18,13 +18,12 @@ const openapm = new OpenAPM({
   customPathsToMask: [/\b\d+(?:,\d+)*\b/gm],
   excludeDefaultLabels: ['host', 'program']
 });
+openapm.on('application_started', () => {
+  console.log('out');
+});
 openapm.instrument('express');
 openapm.instrument('mysql');
 
-openapm.events.on('application_started', () => {
-  console.log('hello world');
-});
-
 const app = express();
 
 const pool = mysql2.createPool(

src/OpenAPM.ts

@@ -1,6 +1,5 @@
 import * as os from 'os';
 import http from 'http';
-import EventEmitter from 'events';
 import ResponseTime from 'response-time';
 import promClient from 'prom-client';
 
@@ -23,6 +22,7 @@ import {
 import { instrumentExpress } from './clients/express';
 import { instrumentMySQL } from './clients/mysql2';
 import { instrumentNestFactory } from './clients/nestjs';
+import { LevitateConfig, LevitateEvents } from './levitate/events';
 
 export type ExtractFromParams = {
   from: 'params';
@@ -62,6 +62,8 @@ export interface OpenAPMOptions {
   customPathsToMask?: Array<RegExp>;
   /** Skip mentioned labels */
   excludeDefaultLabels?: Array<DefaultLabels>;
+  /** Levitate Config */
+  levitateConfig?: LevitateConfig;
 }
 
 export type SupportedModules = 'express' | 'mysql' | 'nestjs';
@@ -74,7 +76,7 @@ const moduleNames = {
 
 const packageJson = getPackageJson();
 
-export class OpenAPM {
+export class OpenAPM extends LevitateEvents {
   private path: string;
   private metricsServerPort: number;
   private environment: string;
@@ -88,9 +90,9 @@ export class OpenAPM {
   private excludeDefaultLabels?: Array<DefaultLabels>;
 
   public metricsServer?: Server;
-  public events: EventEmitter;
 
   constructor(options?: OpenAPMOptions) {
+    super();
     // Initializing all the options
     this.path = options?.path ?? '/metrics';
     this.metricsServerPort = options?.metricsServerPort ?? 9097;
@@ -122,7 +124,7 @@ export class OpenAPM {
     this.extractLabels = options?.extractLabels ?? {};
     this.customPathsToMask = options?.customPathsToMask;
     this.excludeDefaultLabels = options?.excludeDefaultLabels;
-    this.events = new EventEmitter();
+    this.levitateConfig = options?.levitateConfig;
 
     this.initiateMetricsRoute();
     this.initiatePromClient();
@@ -301,7 +303,7 @@ export class OpenAPM {
     try {
       if (moduleName === 'express') {
         const express = require('express');
-        instrumentExpress(express, this._REDMiddleware, this.events);
+        instrumentExpress(express, this._REDMiddleware, this);
       }
       if (moduleName === 'mysql') {
         const mysql2 = require('mysql2');

src/clients/express.ts

@@ -2,11 +2,12 @@ import EventEmitter from 'events';
 import type * as Express from 'express';
 import type { RequestHandler } from 'express';
 import { wrap } from '../shimmer';
+import type OpenAPM from '../OpenAPM';
 
 export const instrumentExpress = (
   express: typeof Express,
   redMiddleware: RequestHandler,
-  events: EventEmitter
+  openapm: OpenAPM
 ) => {
   let redMiddlewareAdded = false;
 
@@ -35,7 +36,15 @@ export const instrumentExpress = (
         this: typeof original,
         ...args: Parameters<typeof original>
       ) {
-        events.emit('application_started');
+        openapm.emit('application_started', {
+          timestamp: new Date().toISOString(),
+          event_name: 'express_app',
+          event_state: 'start',
+          entity_type: '',
+          workspace: '',
+          namespace: '',
+          data_source_name: ''
+        });
         return original.apply(this, args);
       };
     }

src/levitate/events.ts

@@ -0,0 +1,91 @@
+import EventEmitter from 'events';
+
+export interface LevitateConfig {
+  host?: string;
+  orgSlug: string;
+  refreshTokens: {
+    write: string;
+  };
+}
+
+export interface DomainEventsBody {
+  timestamp: string;
+  event_name: string;
+  event_state: 'start' | 'stop';
+  workspace?: string;
+  namespace?: string;
+  entity_type?: string;
+  data_source_name: string;
+}
+
+const defaultHost = 'https://app.last9.io';
+
+export class LevitateEvents extends EventEmitter {
+  private eventsUrl: URL;
+  public levitateConfig?: LevitateConfig;
+  constructor() {
+    super();
+    this.eventsUrl = new URL(
+      `/api/v4/organizations/${this.levitateConfig?.orgSlug}/domain_events`,
+      this.levitateConfig?.host ?? defaultHost
+    );
+    this.initiateEventListeners();
+  }
+
+  // Making the emit and on methods type safe
+  public emit(
+    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);
+  }
+
+  public on(
+    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);
+  }
+
+  public once(
+    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);
+  }
+
+  private initiateEventListeners() {
+    if (typeof this.levitateConfig?.refreshTokens?.write === 'string') {
+      this.once('application_started', this.applicationStarted);
+    }
+  }
+
+  private applicationStarted(body: DomainEventsBody) {
+    // fetch(this.eventsUrl.toString(), {
+    //   method: 'PUT',
+    //   headers: {
+    //     'Content-Type': 'application/json',
+    //     'X-LAST9-API-TOKEN': `Bearer `
+    //   },
+    //   body: {
+
+    //   }
+    // });
+    console.log(body);
+  }
+}