kafka-pub-sub/config/kafka.js

Enterprise-grade Kafka publish/subscribe library for Node.js — producer pool, batch sending, DLQ, SSL/SASL, multi-broker, and real-world industry examples.

const fs = require('fs');
const { Kafka, logLevel } = require('kafkajs');
const config = require('./config');
const WinstonLogCreator = require('./winstonKafkaLogger');

const LOG_LEVEL_MAP = {
  error: logLevel.ERROR,
  warn: logLevel.WARN,
  info: logLevel.INFO,
  debug: logLevel.DEBUG,
};

/**
 * Build optional SSL config from env paths.
 * Returns false when SSL is disabled, or an object with cert/key/ca if enabled.
 */
const buildSslConfig = () => {
  if (!config.kafka_ssl_enabled) return false;

  const ssl = { rejectUnauthorized: config.kafka_ssl_reject_unauthorized };

  if (config.kafka_ssl_ca_path) ssl.ca = [fs.readFileSync(config.kafka_ssl_ca_path, 'utf-8')];
  if (config.kafka_ssl_key_path) ssl.key = fs.readFileSync(config.kafka_ssl_key_path, 'utf-8');
  if (config.kafka_ssl_cert_path) ssl.cert = fs.readFileSync(config.kafka_ssl_cert_path, 'utf-8');

  return ssl;
};

/**
 * Build optional SASL config.
 * Returns undefined when SASL is not configured.
 */
const buildSaslConfig = () => {
  if (!config.kafka_sasl_mechanism) return undefined;

  return {
    mechanism: config.kafka_sasl_mechanism,
    username: config.kafka_sasl_username,
    password: config.kafka_sasl_password,
  };
};

const kafka = new Kafka({
  clientId: config.kafka_client_id,
  brokers: config.kafka_broker_urls, // supports multiple brokers
  ssl: buildSslConfig(),
  sasl: buildSaslConfig(),
  logLevel: LOG_LEVEL_MAP[config.kafka_log_level] || logLevel.ERROR,
  logCreator: WinstonLogCreator,
  retry: {
    initialRetryTime: config.kafka_retry_initial_time,
    retries: config.kafka_retry_count,
    factor: 2, // exponential back-off multiplier
    multiplier: 1.5,
    maxRetryTime: 30000,
  },
});

module.exports = kafka;