Digikare nestjs-azure-eventhub

Transport component for NestJS microservice

The librairies is used and maintained by digikare team. We are open for all contributions!

Description

@digikare/nestjs-azure-eventhub is a transport component provide Event Hub into Nest microservice

Installation

$ npm install @digikare/nestjs-azure-eventhub

# or yarn

$ yarn add @digikare/nestjs-azure-eventhub

How to use

Microservice

import { EventHubServer } from '@digikare/nestjs-azure-eventhub';
// other imports {...}

const app = await NestFactory.createMicroservice(ApplicationModule, {
  startegy: new EventHubServer(
    '<connection_string>',        // the connection string
    '<event_hub_name>',           // the event hub name
    '<optional_consumer_group>',  // optionnal: The consumer group, the default value is $Default
  ),
});

You can also define a specific partitionId to listen if needed (useful for dev/test env).

import { EventHubServer } from '@digikare/nestjs-azure-eventhub';
// other imports {...}

const app = await NestFactory.createMicroservice(ApplicationModule, {
  startegy: new EventHubServer(
    '<connection_string>',          // the connection string
    '<event_hub_name>',             // the event hub name
    '<optional_consumer_group>',    // optionnal: The consumer group, the default value is $Default
    {
      partitionId: '<partition_id>' // optional: the partitionId to listen
    }
  ),
});

And now you can use @EventPattern() and @MessagePattern() decorators!

Checkpoint store

Since 0.1.2, you can add a checkpoint store, that allow your app to treat pending message.

You will need an azure account storage in order to make it works.

import { EventHubServer } from '@digikare/nestjs-azure-eventhub';
// other imports {...}

const app = await NestFactory.createMicroservice(ApplicationModule, {
  startegy: new EventHubServer(
    '<connection_string>',            // the connection string
    '<event_hub_name>',               // the event hub name
    '<optional_consumer_group>',      // optionnal: The consumer group, the default value is $Default
    {
      partitionId: '<partition_id>',  // optional: the partitionId to listen
      checkpointStore: {
        connectionString: '<checkpoint_account_storage_connection_string>',
        containerName: '<checkpoint_container_name>',
      }
    }
  ),
});

Wildcard support on pattern

Wildcard support on pattern can be usefull. When you receive a message, the client will cut out the topic of the event in order to check if handlers are subscribed to these topics.

The restriction at the moment:

• The wildcard char '' must be at the end (eg: audit.*, 'my.scope.on.`)
• The split char is '.'

To enable, just set wildcardSuppprt option to true

import { EventHubServer } from '@digikare/nestjs-azure-eventhub';
// other imports {...}

const app = await NestFactory.createMicroservice(ApplicationModule, {
  startegy: new EventHubServer(
    '<connection_string>',            // the connection string
    '<event_hub_name>',               // the event hub name
    '<optional_consumer_group>',      // optionnal: The consumer group, the default value is $Default
    {
      partitionId: '<partition_id>',  // optional: the partitionId to listen
      wildcardSupport: true,          // <<== Support wildcard
    }
  ),
});

Examples

If you send an event on the following topic : event.subevent.topic The handlePatternMessage will test the following topics :

• *
• event.*
• event.subevent
• event.subevent.*
• event.subevent.topic

Client

import { ConfigModule, ConfigService } from '@nestjs/config';
import { EventHubClient } from '@digikare/nestjs-azure-eventhub';

@Module({
  imports: [
    ConfigModule,
  ],
  providers: {
    {
      provide: 'EVENT_HUB_CLIENT',
      inject: [ConfigService],
      useFactory: (configService: ConfigService) => {
        const connectionString = configService.get<string>('EVENT_HUB_CONNECTION_STRING');
        const eventHubName = configService.get<string>('EVENT_HUB_NAME');
        const partitionId = configService.get<string>('EVENT_HUB_PARTITION_ID'); // optionnal

        return new EventHubClient(
          connectionString,
          {
            eventHubName: eventHubName,
            partitionId: partitionId, // optional - define partitionId if you want sent to only
          }
        );
      },
    }
  },
})

Hint: When you define a partitionId, the configuration will override every message/event to send. Even if you provide a partitionID or partitionKey.

Build

# To install dependencies, first go to root monorepo and run yarn
$ cd ../../
$ yarn

# development
$ cd packages/nestjs-azure-eventhub
$ yarn build

# watch mode
$ cd packages/nestjs-azure-eventhub
$ npm run dev

License

This library is under MIT licensed.