NodeJS GCloud Pub/Sub module

A Google Cloud Pub/Sub library for the NestJS framework. Easily subscribe or publish to topics in Google Pub/Sub.

Features

• Module for sending messages on topics
• Microservice to subscribe to topics in controllers

Todo

• Add Module for subscribing to topics
• Add Microservice client for sending messages on topics

CI and releases

GitHub Actions builds and tests pull requests targeting master and pushes to master. Publishing runs only on pushes to master, after both jobs succeed, using the NPM_TOKEN Actions secret. Coverage reporting uses CODECOV_TOKEN.

Before releasing, bump the version in package.json and package-lock.json to an unpublished version. Every push to master attempts to publish; npm rejects versions that have already been published.

Installation

Yarn

yarn add @ecobee/nodejs-gcloud-pubsub-module

NPM

npm install @ecobee/nodejs-gcloud-pubsub-module --save

Usage

Please refer to the interfaces file to understand parameter and object requirements.

Publish to a topic

Publishing topics follows the classic NestJS pattern of importing a module and injecting a service via dependency injection

Module Setup

Import this module into your module

import { Module } from '@nestjs/common';
import { GcloudPubSubModule } from 'nodejs-gcloud-pubsub-module'
import * as path from 'path';

@Module({
    imports: [
        GcloudPubSubModule.forRoot(moduleOptions: GcloudPubSubModuleOptions),
    ],
})
export class AppModule {}

If you need to populate the moduleOptions with dynamic configuration data use the forRootAsync method. The following example pulls configuration objects using the nestjs-config module

import { Module } from '@nestjs/common'
import { GcloudPubSubModule } from 'nodejs-gcloud-pubsub-module'
import { ConfigService } from 'nestjs-config'
import * as path from 'path'

@Module({
	imports: [
		GcloudPubSubModule.forRootAsync({
			useFactory: (config: ConfigService) => {
				const authOptions = config.get('pubsub.authOptions')
				const publishOptions = config.get('pubsub.publishOptions')
				return {
					authOptions /* Authentication options */,
					publishOptions /* Message publishing options (Optional) */,
				}
			},
			inject: [ConfigService],
		}),
	],
})
export class AppModule {}

Service

With the module imported you can now publish messages to topics

import { Injectable } from '@nestjs/common'
import { GcloudPubSubService } from 'nodejs-gcloud-pubsub-module'

const topic = 'projects/MyProjectId/topics/MyTopic'

@Injectable()
export class MyService {
	constructor(private readonly gcloudPubSubService: GcloudPubSubService) {}

	async publish(payload: PubSubMessage) {
		const serializedPayload = JSON.stringify(payload)
		return await this.gcloudPubSubService.publishMessage(topic, serializedPayload)
	}
}

Subscribing to topics

To subscribe to pubsub message topics we leverage a custom NestJS Microservice. This has the benefit of allowing us to decorate our controllers as we would for standard HTTP requests.

Using a Microservice alongside HTTP can be accomplished by creating a Hybrid NestJS application. Refer to this example to see how this is accomplished.

Microservice setup

import { NestFactory } from '@nestjs/core'
import { GCloudPubSubServer } from 'nodejs-gcloud-pubsub-module'
import { ApplicationModule } from './app.module'

async function bootstrap() {
	const app = await NestFactory.create(ApplicationModule)

	const GCloudPubSubServerOptions = {
		authOptions: {/* Authentication options */}),
		subscriptionIds: ['subscription-name'],
		subscriberOptions: {/* https://googleapis.dev/nodejs/pubsub/latest/global.html#SubscriberOptions */}
	}

	app.connectMicroservice({
		strategy: new GCloudPubSubServer(GCloudPubSubServerOptions),
	})

	await app.startAllMicroservicesAsync()
	await app.listen(3001)
}
bootstrap()

Controller

import { Controller } from '@nestjs/common'
import { Message } from '@google-cloud/pubsub'
import { EventPattern } from '@nestjs/microservices'

@Controller('mycontroller')
export class EntitlementController {
	@EventPattern('subscription-name')
	async handleCreateEntitlement(message: Message) {
		const { data } = message
		const messageData = JSON.parse(data.toString())
		// do stuff with the message
		message.ack()
	}
}