Message Queue

This is a nest library for using SQS​
Quickstart
To use this module locally in dev/testing it's probably easiest to use a SQS compatible server that can run in docker, like Localstack​
Simple docker-compose.yml might look something like
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services:
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  localstack:
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    image: localstack/localstack
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    networks:
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      - local
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    ports:
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      - 4566:4566
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    environment:
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      - SERVICES=sqs
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​
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networks:
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  local:
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Import the queue module in your nest module
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import { QueueModule } from '@island.is/message-queue'
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​
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// Register the queue in your nest module.
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// Note you can call QueueModule.register multiple times with different names
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// if you need mulitple queues
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@Module({
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  imports: [
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    QueueModule.register({
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      queue: {
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        // identifier for using the queue
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        name: 'name-of-queue',
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        // name of queue in AWS
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        queueName: process.env.QUEUE_NAME,
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        // you probably want a dead-letter queue
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        // leave options empty for default settings
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        deadLetterQueue: {},
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      },
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      client: {
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        // endpoint should be 'http://localhost:4566' for localstack but can be left undefined in production
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        endpoint: process.env.SQS_ENDPOINT,
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        region: 'eu-west-1',
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        credentials: {
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          // both keys can be set to 'testing' for use with localstack
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          accessKeyId: process.env.SQS_ACCESS_KEY,
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          secretAccessKey: process.env.SQS_SECRET_ACCESS_KEY,
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        },
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      },
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    }),
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  ],
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})
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export class MyModule {}
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Push messages to the queue
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import { InjectQueue, QueueService } from '@island.is/message-queue'
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import { SomeMessageType } from './types'
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​
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@Injectable()
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export class SomeService {
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  constructor(@InjectQueue('name-of-queue') private queue: QueueService) {}
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​
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  async addToQueue() {
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    // msg can be any json-serializable object
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    const msg: SomeMessageType = { some: 'data' }
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    const uuid = await this.queue.add(msg)
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    // Up to you if or what you use the uuid for
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  }
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}
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Consume messages from the queue
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import { InjectWorker, WorkerService } from '@island.is/message-queue'
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import { SomeMessageType } from './types'
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​
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@Injectable()
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export class SomeWorkerService {
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  constructor(@InjectWorker('name-of-queue') private worker: WorkerService) {}
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​
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  async run() {
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    await this.worker.run(async (message: SomeMessageType) => {
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      console.log('Yay, got message', message)
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    })
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  }
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}
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Run the worker from your application main.ts
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const worker = async () => {
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  const app = await NestFactory.createApplicationContext(AppModule)
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  app.enableShutdownHooks()
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  await app.get(SomeWorkerService).run()
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}
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​
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// might need some check here if we should run the worker or the main application/webserver
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worker()
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System Flow Sequence Diagram
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sequenceDiagram
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    autonumber
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    Institution->>Advania:adds new message in mailbox
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    Advania->>User-Notification-Service:xroad:sends message notification
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    User-Notification-Service->>AWS SQS:adds processed notification to queue
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    loop
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    User-Notification-Worker->>AWS SQS:requests 10 notifications
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    AWS SQS->>User-Notification-Worker:responds with 0-10 notifications
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    end
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    loop if worker throws an unexpected error, it will try 2 more times with 10 minute interval
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    User-Notification-Worker->>User-Profile-Service:requests notification settings
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    User-Profile-Service->>User-Notification-Worker:returns user settings and tokens
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    end
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    User-Notification-Worker->>Firebase Cloud Messaging: sends notification
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    Firebase Cloud Messaging->>island.is app:sends notification
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Running unit tests
Run yarn test message-queue to execute the unit tests via Jest.

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Quickstart

System Flow Sequence Diagram

Running unit tests