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https://github.com/p-fedyukovich/nestjs-google-pubsub-microservice
Custom Google Cloud Pub/Sub microservice transport for Nest framework (node.js)
https://github.com/p-fedyukovich/nestjs-google-pubsub-microservice
google-pubsub microservices nestjs nestjs-library nestjs-microservices nodejs typescript
Last synced: about 2 hours ago
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Custom Google Cloud Pub/Sub microservice transport for Nest framework (node.js)
- Host: GitHub
- URL: https://github.com/p-fedyukovich/nestjs-google-pubsub-microservice
- Owner: p-fedyukovich
- License: mit
- Created: 2021-02-02T17:46:30.000Z (almost 4 years ago)
- Default Branch: master
- Last Pushed: 2024-12-15T14:56:50.000Z (about 1 month ago)
- Last Synced: 2025-01-08T21:43:14.982Z (14 days ago)
- Topics: google-pubsub, microservices, nestjs, nestjs-library, nestjs-microservices, nodejs, typescript
- Language: TypeScript
- Homepage: https://nestjs.com
- Size: 334 KB
- Stars: 86
- Watchers: 1
- Forks: 14
- Open Issues: 7
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# NestJS Google Cloud Pub/Sub Microservice Transport
### Google Cloud Pub/Sub
[Pub/Sub](https://cloud.google.com/pubsub) is an asynchronous messaging service that decouples services that produce events from services that process events.
You can use Pub/Sub as messaging-oriented middleware or event ingestion and delivery for streaming analytics pipelines.
Pub/Sub offers durable message storage and real-time message delivery with high availability and consistent performance at scale
#### Installation
To start building Pub/Sub-based microservices, first install the required packages:
```bash
$ npm i --save @google-cloud/pubsub nestjs-google-pubsub-microservice
```
#### Overview
To use the Pub/Sub transporter, pass the following options object to the `createMicroservice()` method:
```typescript
const app = await NestFactory.createMicroservice(
ApplicationModule,
{
strategy: new GCPubSubServer({
topic: 'cats_topic',
subscription: 'cats_subscription',
client: {
projectId: 'microservice',
},
}),
},
);
```
#### Options
The `options` property is specific to the chosen transporter. The GCloud Pub/Sub transporter exposes the properties described below.
topic
Topic name which your server subscription will belong to
subscription
Subscription name which your server will listen to
replyTopic
Topic name which your client subscription will belong to
replySubscription
Subscription name which your client will listen to
noAck
If false, manual acknowledgment mode enabled
init
If false, topics and subscriptions will not be created, only validated
checkExistence
If false, topics and subscriptions will not be checked, only used. This only applies when init is false
useAttributes
Only applicable for client. If true, pattern and correlationId will be sent via message attributes. This is useful if message consumer is not NestJs microservice or you have message filtering on subscription
client
Additional client options (read more here)
publisher
Additional topic publisher options (read more here)
subscriber
Additional subscriber options (read more here)
scopedEnvKey
Scope topics and subscriptions to avoid losing messages when several people are working on the same code base. Will prefixes topics and subscriptions with this key (read more here)
#### Client
```typescript
const client = new GCPubSubClient({
client: {
apiEndpoint: 'localhost:8681',
projectId: 'microservice',
},
});
client
.send('pattern', 'Hello world!')
.subscribe((response) => console.log(response));
```
#### Context
In more sophisticated scenarios, you may want to access more information about the incoming request. When using the Pub/Sub transporter, you can access the `GCPubSubContext` object.
```typescript
@MessagePattern('notifications')
getNotifications(@Payload() data: number[], @Ctx() context: GCPubSubContext) {
console.log(`Pattern: ${context.getPattern()}`);
}
```
To access the original Pub/Sub message (with the `attributes`, `data`, `ack` and `nack`), use the `getMessage()` method of the `GCPubSubContext` object, as follows:
```typescript
@MessagePattern('notifications')
getNotifications(@Payload() data: number[], @Ctx() context: GCPubSubContext) {
console.log(context.getMessage());
}
```
#### Message acknowledgement
To make sure a message is never lost, Pub/Sub supports [message acknowledgements](https://cloud.google.com/pubsub/docs/subscriber#at-least-once-delivery). An acknowledgement is sent back by the consumer to tell Pub/Sub that a particular message has been received, processed and that Pub/Sub is free to delete it. If a consumer dies (its subscription is closed, connection is closed, or TCP connection is lost) without sending an ack, Pub/Sub will understand that a message wasn't processed fully and will re-deliver it.
To enable manual acknowledgment mode, set the `noAck` property to `false`:
```typescript
{
replyTopic: 'cats_topic_reply',
replySubscription: 'cats_subscription_reply',
noAck: false,
client: {
projectId: 'microservice',
},
},
```
When manual consumer acknowledgements are turned on, we must send a proper acknowledgement from the worker to signal that we are done with a task.
```typescript
@MessagePattern('notifications')
getNotifications(@Payload() data: number[], @Ctx() context: GCPubSubContext) {
const originalMsg = context.getMessage();
originalMsg.ack();
}
```
#### Shutdown
Pub/Sub requires a graceful shutdown properly configured in order to work correctly, otherwise some messages acknowledges can be lost. Therefore, don't forget to call client close:
```typescript
export class GCPubSubController implements OnApplicationShutdown {
client: ClientProxy;
constructor() {
this.client = new GCPubSubClient({});
}
onApplicationShutdown() {
return this.client.close();
}
}
```