Implement distributed event handler to propagate ad deletion

src/app.constants.ts

@@ -15,6 +15,9 @@ export const MATCHER_AD_CREATION_FAILED_ROUTING_KEY =
 export const AD_CREATED_MESSAGE_HANDLER = 'adCreated';
 export const AD_CREATED_ROUTING_KEY = 'ad.created';
 export const AD_CREATED_QUEUE = 'matcher.ad.created';
+export const AD_DELETED_MESSAGE_HANDLER = 'adDeleted';
+export const AD_DELETED_ROUTING_KEY = 'ad.deleted';
+export const AD_DELETED_QUEUE = 'matcher.ad.deleted';
 
 // health
 export const GRPC_HEALTH_PACKAGE_NAME = 'health';

src/modules/ad/ad.module.ts

@@ -43,6 +43,7 @@ import { TimeConverter } from './infrastructure/time-converter';
 import { TimezoneFinder } from './infrastructure/timezone-finder';
 import { MatchGrpcController } from './interface/grpc-controllers/match.grpc-controller';
 import { AdCreatedMessageHandler } from './interface/message-handlers/ad-created.message-handler';
+import { AdDeletedMessageHandler } from './interface/message-handlers/ad-deleted.message-handler';
 import { MatchMapper } from './match.mapper';
 import { MatchingMapper } from './matching.mapper';
 
@@ -97,7 +98,7 @@ const imports = [
 
 const grpcControllers = [MatchGrpcController];
 
-const messageHandlers = [AdCreatedMessageHandler];
+const messageHandlers = [AdCreatedMessageHandler, AdDeletedMessageHandler];
 
 const eventHandlers: Provider[] = [
   PublishMessageWhenMatcherAdIsCreatedDomainEventHandler,

src/modules/ad/interface/message-handlers/ad-deleted.message-handler.ts

@@ -0,0 +1,32 @@
+import { RabbitSubscribe } from '@mobicoop/message-broker-module';
+import { DeleteAdCommand } from '@modules/ad/core/application/commands/delete-ad/delete-ad.command';
+import { Injectable } from '@nestjs/common';
+import { CommandBus } from '@nestjs/cqrs';
+import {
+  AD_DELETED_MESSAGE_HANDLER,
+  AD_DELETED_ROUTING_KEY,
+} from '@src/app.constants';
+import { AdReference } from './ad.types';
+
+@Injectable()
+export class AdDeletedMessageHandler {
+  constructor(private readonly commandBus: CommandBus) {}
+
+  @RabbitSubscribe({
+    name: AD_DELETED_MESSAGE_HANDLER,
+    routingKey: AD_DELETED_ROUTING_KEY,
+  })
+  public async adDeleted(message: string): Promise<void> {
+    try {
+      const deletedAd: AdReference = JSON.parse(message);
+      await this.commandBus.execute(
+        new DeleteAdCommand({
+          id: deletedAd.aggregateId,
+        }),
+      );
+    } catch (error: any) {
+      // do not throw error to acknowledge incoming message
+      // error handling should be done in the command handler, if relevant
+    }
+  }
+}

src/modules/ad/interface/message-handlers/ad.types.ts

@@ -1,7 +1,10 @@
 import { Frequency } from '@modules/ad/core/domain/ad.types';
 
-export type Ad = {
+export type AdReference = {
   aggregateId: string;
+};
+
+export type Ad = AdReference & {
   driver: boolean;
   passenger: boolean;
   frequency: Frequency;

src/modules/ad/tests/unit/interface/ad-deleted.message-handler.spec.ts

@@ -0,0 +1,44 @@
+import { AdDeletedMessageHandler } from '@modules/ad/interface/message-handlers/ad-deleted.message-handler';
+import { CommandBus } from '@nestjs/cqrs';
+import { Test, TestingModule } from '@nestjs/testing';
+
+const adDeletedMessage =
+  '{"aggregateId":"4eb6a6af-ecfd-41c3-9118-473a507014d4"}';
+
+const mockCommandBus = {
+  execute: jest.fn(),
+};
+
+describe('Ad Deleted Message Handler', () => {
+  let adDeletedMessageHandler: AdDeletedMessageHandler;
+
+  beforeAll(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [
+        {
+          provide: CommandBus,
+          useValue: mockCommandBus,
+        },
+        AdDeletedMessageHandler,
+      ],
+    }).compile();
+
+    adDeletedMessageHandler = module.get<AdDeletedMessageHandler>(
+      AdDeletedMessageHandler,
+    );
+  });
+
+  afterEach(async () => {
+    jest.clearAllMocks();
+  });
+
+  it('should be defined', () => {
+    expect(adDeletedMessageHandler).toBeDefined();
+  });
+
+  it('should call the delete command', async () => {
+    jest.spyOn(mockCommandBus, 'execute');
+    await adDeletedMessageHandler.adDeleted(adDeletedMessage);
+    expect(mockCommandBus.execute).toHaveBeenCalledTimes(1);
+  });
+});

src/modules/messager/messager.module.ts

@@ -1,17 +1,20 @@
-import { Module, Provider } from '@nestjs/common';
-import { MESSAGE_PUBLISHER } from './messager.di-tokens';
 import {
   MessageBrokerModule,
   MessageBrokerModuleOptions,
   MessageBrokerPublisher,
 } from '@mobicoop/message-broker-module';
+import { Module, Provider } from '@nestjs/common';
 import { ConfigModule, ConfigService } from '@nestjs/config';
 import {
   AD_CREATED_MESSAGE_HANDLER,
   AD_CREATED_QUEUE,
   AD_CREATED_ROUTING_KEY,
+  AD_DELETED_MESSAGE_HANDLER,
+  AD_DELETED_QUEUE,
+  AD_DELETED_ROUTING_KEY,
   SERVICE_NAME,
 } from '@src/app.constants';
+import { MESSAGE_PUBLISHER } from './messager.di-tokens';
 
 const imports = [
   MessageBrokerModule.forRootAsync({
@@ -33,6 +36,10 @@ const imports = [
           routingKey: AD_CREATED_ROUTING_KEY,
           queue: AD_CREATED_QUEUE,
         },
+        [AD_DELETED_MESSAGE_HANDLER]: {
+          routingKey: AD_DELETED_ROUTING_KEY,
+          queue: AD_DELETED_QUEUE,
+        },
       },
     }),
   }),