microservice-support-toolkit/lib/core/spring-cloud-bus.js

A global module with commons utilities for microservice support

const amqp = require('amqplib/callback_api');
const { fetch } = require('./spring-cloud-config');
const logger = require('./logger');

const subscribeToSpringCloudBusTopic = ({
  username,
  password,
  host,
  port
}) => (
  new Promise((resolve, reject) => {

    const RABBITMQ_URL = `amqp://${username}:${password}@${host}:${port}`;

    amqp.connect(RABBITMQ_URL, (error0, connection) => {
      if (!connection) {
        logger.error('Could not connect to RabbitMQ');
        process.exit(1);
      }
      if (error0) {
        return reject(error0);
      }
      connection.createChannel((error1, channel) => {
        if (error1) return reject(error1);
        const exchange = 'springCloudBus';
        channel.assertExchange(exchange, 'topic', { durable: true });
        channel.assertQueue('', {
          autoDelete: true,
          exclusive: true
        }, (error2, q) => {
          if (error2) return reject(error2);
          logger.info(`Waiting for configs = require(Spring Cloud Bus | exchange: ${exchange} | pattern # | bindQueue: ${q.queue}`);
          channel.bindQueue(q.queue, exchange, '#');
          channel.consume(q.queue, (msg) => {
            fetch().then(() => {
              const event = JSON.parse(msg.content.toString());
              logger.info(`${new Date(event.timestamp)} ${event.type} -> ${event.originService} -> ${event.destinationService}`)
            })
          }, { noAck: true });
          resolve();
        });
      });
    });
  })
);

module.exports = {
  subscribeToSpringCloudBusTopic
};