Implemented ALB support

Based on:
  - dherault#1250 by bayoumymac
  - https://github.com/tmaslen/serverless-local-alb-example by tmaslen

Author: ihendriks

src/ServerlessOffline.js

@@ -23,6 +23,8 @@ export default class ServerlessOffline {
 
   #webSocket = null
 
+  #alb = null
+
   constructor(serverless, cliOptions) {
     this.#cliOptions = cliOptions
     this.#serverless = serverless
@@ -61,7 +63,7 @@ export default class ServerlessOffline {
   async start() {
     this.#mergeOptions()
 
-    const { httpEvents, lambdas, scheduleEvents, webSocketEvents } =
+    const { httpEvents, lambdas, scheduleEvents, webSocketEvents, albEvents } =
       this.#getEvents()
 
     // if (lambdas.length > 0) {
@@ -70,6 +72,10 @@ export default class ServerlessOffline {
 
     const eventModules = []
 
+    if (albEvents.length > 0) {
+      eventModules.push(this.#createAlb(albEvents))
+    }
+
     if (httpEvents.length > 0) {
       eventModules.push(this.#createHttp(httpEvents))
     }
@@ -99,6 +105,10 @@ export default class ServerlessOffline {
       eventModules.push(this.#lambda.stop(SERVER_SHUTDOWN_TIMEOUT))
     }
 
+    if (this.#alb) {
+      eventModules.push(this.#alb.stop(SERVER_SHUTDOWN_TIMEOUT))
+    }
+
     if (this.#http) {
       eventModules.push(this.#http.stop(SERVER_SHUTDOWN_TIMEOUT))
     }
@@ -210,6 +220,18 @@ export default class ServerlessOffline {
     return this.#webSocket.start()
   }
 
+  async #createAlb(events, skipStart) {
+    const { default: Alb } = await import('./events/alb/index.js')
+
+    this.#alb = new Alb(this.#serverless, this.#options, this.#lambda)
+
+    this.#alb.create(events)
+
+    if (!skipStart) {
+      await this.#alb.start()
+    }
+  }
+
   #mergeOptions() {
     const {
       service: { custom = {}, provider },
@@ -264,6 +286,7 @@ export default class ServerlessOffline {
     const lambdas = []
     const scheduleEvents = []
     const webSocketEvents = []
+    const albEvents = []
 
     const functionKeys = service.getAllFunctions()
 
@@ -277,7 +300,7 @@ export default class ServerlessOffline {
       const events = service.getAllEventsInFunction(functionKey) || []
 
       events.forEach((event) => {
-        const { http, httpApi, schedule, websocket } = event
+        const { http, httpApi, schedule, websocket, alb } = event
 
         if ((http || httpApi) && functionDefinition.handler) {
           const httpEvent = {
@@ -357,6 +380,14 @@ export default class ServerlessOffline {
             websocket,
           })
         }
+
+        if (alb) {
+          albEvents.push({
+            alb,
+            functionKey,
+            handler: functionDefinition.handler,
+          })
+        }
       })
     })
 
@@ -374,6 +405,7 @@ export default class ServerlessOffline {
     }
 
     return {
+      albEvents,
       httpEvents,
       lambdas,
       scheduleEvents,

src/config/commandOptions.js

@@ -1,4 +1,8 @@
 export default {
+  albPort: {
+    type: 'string',
+    usage: 'ALB port to listen on. Default: 3003',
+  },
   apiKey: {
     type: 'string',
     usage:

src/config/defaultOptions.js

@@ -1,6 +1,7 @@
 import { createApiKey } from '../utils/index.js'
 
 export default {
+  albPort: 3003,
   apiKey: createApiKey(),
   corsAllowCredentials: true, // TODO no CLI option
   corsAllowHeaders: 'accept,content-type,x-api-key,authorization',

src/events/alb/Alb.js

@@ -0,0 +1,32 @@
+import AlbEventDefinition from './AlbEventDefinition.js'
+import HttpServer from './HttpServer.js'
+
+export default class Alb {
+  #httpServer = null
+
+  constructor(serverless, options, lambda) {
+    this.#httpServer = new HttpServer(serverless, options, lambda)
+  }
+
+  start() {
+    return this.#httpServer.start()
+  }
+
+  stop(timeout) {
+    return this.#httpServer.stop(timeout)
+  }
+
+  #createEvent(functionKey, rawAlbEventDefinition) {
+    const albEvent = new AlbEventDefinition(rawAlbEventDefinition)
+
+    this.#httpServer.createRoutes(functionKey, albEvent)
+  }
+
+  create(events) {
+    events.forEach(({ functionKey, alb }) => {
+      this.#createEvent(functionKey, alb)
+    })
+
+    this.#httpServer.writeRoutesTerminal()
+  }
+}

src/events/alb/AlbEventDefinition.js

@@ -0,0 +1,22 @@
+const { assign } = Object
+
+export default class AlbEventDefinition {
+  constructor(rawAlbEventDefinition) {
+    let listenerArn
+    let priority
+    let conditions
+    let rest
+
+    if (typeof rawAlbEventDefinition === 'string') {
+      ;[listenerArn, priority, conditions] = rawAlbEventDefinition.split(' ')
+    } else {
+      ;({ listenerArn, priority, conditions, ...rest } = rawAlbEventDefinition)
+    }
+
+    this.listenerArn = listenerArn
+    this.priority = priority
+    this.conditions = conditions
+
+    assign(this, rest)
+  }
+}