feat(microservices): Allow RegExps in Patterns for Kafka

closes nestjs#3083

Author: edeesis

Diff for: integration/microservices/e2e/sum-kafka.spec.ts

@@ -96,7 +96,21 @@ describe.skip('Kafka transport', function () {
       .send()
       .end(() => {
         setTimeout(() => {
-          expect(KafkaController.IS_NOTIFIED).to.be.true;
+          expect(KafkaMessagesController.IS_NOTIFIED).to.be.true;
+          done();
+        }, 1000);
+      });
+  });
+
+  it(`/POST (async event notification)`, done => {
+    request(server)
+      .post('/notifyRegex')
+      .send()
+      .end(() => {
+        setTimeout(() => {
+          expect(KafkaMessagesController.IS_REGEX_NOTIFIED).to.be.eq(
+            'regex.notify.test-0',
+          );
           done();
         }, 1000);
       });

Diff for: integration/microservices/src/kafka/kafka.controller.ts

@@ -15,7 +15,6 @@ import { UserDto } from './dtos/user.dto';
 @Controller()
 export class KafkaController implements OnModuleInit, OnModuleDestroy {
   protected readonly logger = new Logger(KafkaController.name);
-  static IS_NOTIFIED = false;
   static MATH_SUM = 0;
 
   @Client({
@@ -133,6 +132,11 @@ export class KafkaController implements OnModuleInit, OnModuleDestroy {
     return this.client.emit('notify', { notify: true });
   }
 
+  @Post('notifyRegex')
+  async sendRegexNotification(): Promise<any> {
+    return this.client.emit('regex.notify.test-0', { notify: true });
+  }
+
   // Complex data to send.
   @Post('/user')
   @HttpCode(200)

Diff for: integration/microservices/src/kafka/kafka.messages.controller.ts

@@ -1,5 +1,10 @@
 import { Controller, Logger } from '@nestjs/common';
-import { EventPattern, MessagePattern } from '@nestjs/microservices';
+import {
+  Ctx,
+  EventPattern,
+  KafkaContext,
+  MessagePattern,
+} from '@nestjs/microservices';
 import { BusinessDto } from './dtos/business.dto';
 import { UserDto } from './dtos/user.dto';
 import { BusinessEntity } from './entities/business.entity';
@@ -10,6 +15,7 @@ import { KafkaController } from './kafka.controller';
 export class KafkaMessagesController {
   protected readonly logger = new Logger(KafkaMessagesController.name);
   static IS_NOTIFIED = false;
+  static IS_REGEX_NOTIFIED: any = false;
 
   @MessagePattern('math.sum.sync.kafka.message')
   mathSumSyncKafkaMessage(data: any) {
@@ -53,7 +59,12 @@ export class KafkaMessagesController {
 
   @EventPattern('notify')
   eventHandler(data: any) {
-    KafkaController.IS_NOTIFIED = data.value.notify;
+    KafkaMessagesController.IS_NOTIFIED = data.value.notify;
+  }
+
+  @EventPattern(/regex\.notify\.test-[0-9]*/)
+  regexHandler(data: any, @Ctx() context: KafkaContext) {
+    KafkaMessagesController.IS_REGEX_NOTIFIED = context.getTopic();
   }
 
   // Complex data to send.

Diff for: packages/microservices/server/server-kafka.ts

@@ -28,6 +28,7 @@ import { KafkaLogger, KafkaParser } from '../helpers';
 import {
   CustomTransportStrategy,
   KafkaOptions,
+  MessageHandler,
   OutgoingResponse,
   ReadPacket,
 } from '../interfaces';
@@ -49,6 +50,8 @@ export class ServerKafka extends Server implements CustomTransportStrategy {
   protected clientId: string;
   protected groupId: string;
 
+  protected registeredPatterns: any[];
+
   constructor(protected readonly options: KafkaOptions['options']) {
     super();
 
@@ -120,13 +123,12 @@ export class ServerKafka extends Server implements CustomTransportStrategy {
   }
 
   public async bindEvents(consumer: Consumer) {
-    const registeredPatterns = [...this.messageHandlers.keys()];
     const consumerSubscribeOptions = this.options.subscribe || {};
 
-    if (registeredPatterns.length > 0) {
+    if (this.registeredPatterns.length > 0) {
       await this.consumer.subscribe({
         ...consumerSubscribeOptions,
-        topics: registeredPatterns,
+        topics: this.registeredPatterns,
       });
     }
 
@@ -317,4 +319,14 @@ export class ServerKafka extends Server implements CustomTransportStrategy {
   protected initializeDeserializer(options: KafkaOptions['options']) {
     this.deserializer = options?.deserializer ?? new KafkaRequestDeserializer();
   }
+
+  public addHandler(
+    pattern: any,
+    callback: MessageHandler,
+    isEventHandler: boolean = false,
+    extras: Record<string, any> = {},
+  ) {
+    this.registeredPatterns.push(pattern);
+    super.addHandler(pattern, callback, isEventHandler, extras);
+  }
 }

Diff for: packages/microservices/test/server/server-kafka.spec.ts

@@ -180,10 +180,26 @@ describe('ServerKafka', () => {
       await server.listen(callback);
 
       const pattern = 'test';
-      const handler = sinon.spy();
-      (server as any).messageHandlers = objectToMap({
-        [pattern]: handler,
-      });
+      (server as any).registeredPatterns = [pattern];
+
+      await server.bindEvents((server as any).consumer);
+
+      expect(subscribe.called).to.be.true;
+      expect(
+        subscribe.calledWith({
+          topics: [pattern],
+        }),
+      ).to.be.true;
+
+      expect(run.called).to.be.true;
+      expect(connect.called).to.be.true;
+    });
+    it('should call subscribe and run on consumer when there are RegExp messageHandlers', async () => {
+      (server as any).logger = new NoopLogger();
+      await server.listen(callback);
+
+      const pattern = /test/;
+      (server as any).registeredPatterns = [pattern];
 
       await server.bindEvents((server as any).consumer);
 
@@ -204,10 +220,7 @@ describe('ServerKafka', () => {
       await server.listen(callback);
 
       const pattern = 'test';
-      const handler = sinon.spy();
-      (server as any).messageHandlers = objectToMap({
-        [pattern]: handler,
-      });
+      (server as any).registeredPatterns = [pattern];
 
       await server.bindEvents((server as any).consumer);
 

Diff for: packages/microservices/utils/transform-pattern.utils.ts

@@ -24,6 +24,9 @@ export function transformPatternToRoute(pattern: MsPattern): string {
   if (!isObject(pattern)) {
     return pattern;
   }
+  if (pattern instanceof RegExp) {
+    return pattern.source;
+  }
 
   const sortedKeys = Object.keys(pattern).sort((a, b) =>
     ('' + a).localeCompare(b),