@erento/nestjs-module-google-pubsub

NestJS Google Pub/Sub module

Easy way to publish messages to Google Pub/Sub. Supports encrypting the message.

How to use it

1. Import

   Import this module in the module you want to use it: typescript imports: [ PubSubModule.forRoot( {keyFilename: PUBSUB_CONFIG}, X_PUBSUB_KEY, X_PUBSUB_ENCRYPTION_KEY, SERVICE_IDENTIFIER ) ]

   • PUBSUB_CONFIG is the path to the file with the service account, e.g.: ./config/pubsub.config.json
   • X_PUBSUB_KEY is a secret signature key to encrypt the message. This is necessary for write, but can be used in read operation to verify a signature.
   • X_PUBSUB_ENCRYPTION_KEY is a secret encryption key. This is necessary for write and read.
   • SERVICE_IDENTIFIER is a string represantation of a sender, e.g. "price-service", "user-service", etc.

2. Usage

   • Publish a messages:

     await this.pubSubService.publishMessage<MyMessage>(
         'projects/project-name/topics/topic-name',
         { // this can be any object, in this case: MyMessage
             text: `some message`,
         },
         {
             myAttribute: 'any other attribute you need to pass',
         },
     );
     

   • Read a messages:

     private async onSubscriptionMessage (message: EncodedMessage): Promise<void> {
         try {
             await this.pubSubService.verifyMessage(message);
             const decryptedMessage: string = await this.pubSubService.decryptMessage(message);
             const parsedMessage: PubSubMessage<MyMessage> = JSON.parse(decryptedMessage);
     
             // process parsed message parsedMessage looks like: {meta: object, payload: MyMessage}
     
             message.ack();
         } catch (e) {
             message.nack();
         }
     }
     

   • Pull for messages: In constructor run this.registerPubSubPull();. The implementation can look as follows:

     import {EncodedMessage, PubSubMessage, PubSubService} from '@erento/nestjs-module-google-pubsub';
     
     interface MyMessage {}
     
     class MyClass {
         constructor(private readonly pubSubService: PubSubService) {
             this.registerPubSubPull();
         }
     
         private registerPubSubPull (): void {
             this.pubSubService.listenOnSubscription(
                 'projects/project-name/subscriptions/pull-subscription-name',
                 this.onSubscriptionMessage.bind(this),
                 this.onSubscriptionError.bind(this),
             );
         }
     
         private async onSubscriptionMessage (message: EncodedMessage): Promise<void> {
             // see section above how to read a message
         }
     
         private onSubscriptionError (message: EncodedRequest): void {
             Log.error(`Unexpected error happened with a message: ${JSON.stringify(message)}`);
         }
     }
     

Stay in touch

• Erento's developers

License

This module is MIT licensed.