@yourrentals/cloudevent-receiver-nestjs

This library defines a plugin for NestJS to receive messages from the message bus.

Installation

yarn add @yourrentals/cloudevent-receiver-nestjs @golevelup/nestjs-discovery

Usage

This plugin requires NestJS Raw Body parsing for signature verification, and CloudEvent Body Parser for CloudEvent parsing (in structured mode)

import { NestFactory } from '@nestjs/core';
import type { NestExpressApplication } from '@nestjs/platform-express';
import { AppModule } from './app.module';

// in the "bootstrap" function
const app = await NestFactory.create<NestExpressApplication>(AppModule, {
  rawBody: true,
});

// Support CloudEvent - Structured mode parsing
app.useBodyParser('json', {
  type: 'application/cloudevents+json',
});

await app.listen(3000);

import {
  CloudEventReceiverModule,
  EventHandler,
  WebhookSignatureV1HmacPlugin,
  CloudEvent
} from '@yourrentals/cloudevent-receiver-nestjs'

@Injectable()
class MessagebusHandlerService {
  @EventHandler('my-queue')
  async handleMyQueue(event: CloudEvent) {
    // ...
  }

  @EventHandler('my-other-queue', false /* event is not CloudEvent */)
  async handleSqsQueue(event: Message) {
    // ...
  }
}

@Module({
  imports: [
    CloudEventReceiverModule.forRoot({
      pathPrefix: '/message-bus',
      verifierPlugins: [new WebhookSignatureV1HmacPlugin('secret')],
    }),
  ],
  providers: [MessagebusHandlerService],
})

import Axios from 'axios';

const main = async () => {
	// Queue name defined in the receiver are automatically registered
	await Axios.post('http://localhost:3000/message-bus/my-queue', {
		headers: {
			'ce-specversion': '1.0',
			'ce-type': 'my-event',
			'ce-source': 'my-source',
			'ce-id': 'my-id',
			'ce-time': '2020-01-01T00:00:00Z',
			'ce-datacontenttype': 'application/json',
			'ce-dataschema': 'http://myschema.com',
			'ce-subject': 'my-subject',
			'ce-signature': 'my-signature',
		},
		body: {
			foo: 'bar',
		},
	});
};

Authentication

NestJS usually have global authentication that will impede operations of this module, as the routes are considered public route. To disable authentication for the routes, you can use the routeDecorator module option:

import { Module, SetMetadata } from '@nestjs/common';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import {
  CloudEventReceiverModule,
  WebhookSignatureV1HmacPlugin,
} from '@yourrentals/cloudevent-receiver-nestjs';
import { APP_GUARD } from '@nestjs/core';
import { AuthGuardGuard } from './auth-guard/auth-guard.guard';

@Module({
  imports: [
    CloudEventReceiverModule.forRoot({
      // Set the route decorator so that your authentication guard will treat the route as public
      routeDecorator: SetMetadata('isPublic', true),
      verifierPlugins: [new WebhookSignatureV1HmacPlugin('secret2')],
    }),
  ],
  controllers: [AppController],
  providers: [AppService, { provide: APP_GUARD, useClass: AuthGuardGuard }],
})
export class AppModule {}

Raw Mode

The library can receive messages from any sources so long that it implements the Webhook Signature. To disable parsing as cloudevent, set the isCloudEvent option in decorator to false.

By default, the event type is assumed to be a SQS Message

import { Injectable } from '@nestjs/common';
import {
  EventHandler,
  SqsMessage,
} from '@yourrentals/cloudevent-receiver-nestjs';

@Injectable()
export class AppService {
  @EventHandler('test', /* isCloudEvent */ false)
  async handle(event: SqsMessage) {
    console.log(event);
  }
}

Errors

The library defines the following errors:

| Error | Description | Expected HTTP status code | Retryable | |------------------------|-----------------------------------------|---------------------------|-----------| | InvalidSignatureError | The signature of the message is invalid | 401 | No | | UnparsableMessageError | The message is not a valid CloudEvent | 400 | No | | NotFoundError | The queue name is not registered | 404 | Yes | | ConflictError | The queue name is already registered | 409 | Yes | | TooManyRequestsError | The queue is currently busy | 429 | Yes | | ClientError | Any other client error | 400 | No | | ServerError | Any other server error | 500 | Yes |