Kafka non-blocking retry topic for nestjs microservice.
See more: Spring Kafka Non-Blocking Retries and Dead Letter Topics
// main.ts
import {KafkaOptions} from "@nestjs/microservices";
const kafkaOptions: KafkaOptions = {};
const app = await NestFactory.create(AppModule);
app.connectMicroservice({
strategy: new KafkaStrategy(kafkaOptions)
});
await app.startAllMicroservices();Decorate your controllers with the @KafkaListener and @KafkaDlt decorators:
// controller.ts
@Controller()
export class UserController {
@KafkaListener('user-created', {
attempts: 2,
backoff: {
delay: 200,
multiplier: 2.0,
},
autoCreateRetryTopic: true,
})
public async message(
@Payload() data,
@Ctx() ctx: KafkaContext
) {
try {
//Todo something
} catch (err) {
// must throw RpcException
throw new RpcException('abcd');
}
}
@KafkaDlt('user-created')
public async handleDeadLetterTopic(
@Payload() data,
@Ctx() ctx: KafkaContext
) {
//Todo something to report
}
}With this @KafkaListener, the first delivery attempt fails and the record is sent to a topic user-created-retry-1 configured for a 200ms delay. When that delivery fails, the record is sent to a topic user-created-retry-2 with a 400ms delay and, finally, to a dead letter topic user-created-dlt handled by @KafkaDlt.