ClientKafkaProxy

Kind: Interface

Source: packages/microservices/interfaces/client-kafka-proxy.interface.ts

Part of: Microservices

ClientKafkaProxy defines the Kafka client resources managed by a microservice client proxy. It exposes nullable consumer and producer references so the proxy can create, reuse, and clean up Kafka connections during its lifecycle.

Properties

Diagram

mermaid
graph LR
  Proxy[Kafka Client Proxy] --> Interface[ClientKafkaProxy]
  Interface --> Consumer[consumer: Consumer | null]
  Interface --> Producer[producer: Producer | null]
  Consumer --> Kafka[Kafka Broker]
  Producer --> Kafka

Usage

ts
import type { Consumer, Producer } from 'kafkajs';
import type { ClientKafkaProxy } from './client-kafka-proxy.interface';

class KafkaClient implements ClientKafkaProxy {
  consumer: Consumer | null = null;
  producer: Producer | null = null;

  async publish(topic: string, message: unknown) {
    if (!this.producer) {
      throw new Error('Kafka producer has not been initialized.');
    }

    await this.producer.send({
      topic,
      messages: [{ value: JSON.stringify(message) }],
    });
  }

  async close() {
    await this.consumer?.disconnect();
    await this.producer?.disconnect();

    this.consumer = null;
    this.producer = null;
  }
}

AI Coding Instructions

• Treat consumer and producer as optional lifecycle-managed resources; always handle the null case before calling Kafka methods.
• Initialize Kafka clients before subscribing, consuming, or publishing messages, and reset references to null after disconnecting.
• Use the KafkaJS Consumer and Producer types when implementing this interface.
• Ensure shutdown logic disconnects both resources safely, using optional chaining or explicit null checks.