microservice-support-toolkit/lib/core/eureka.js

A global module with commons utilities for microservice support

const { promisify } = require('util');
const { Eureka } = require('eureka-js-client');
const ip = require('ip');
const logger = require('./logger');

let client = null;

const register = ({
  appName,
  hostName,
  port,
  eurekaHostName,
  eurekaPort = 8761,
  registerWithEureka = true,
  fetchRegistry = true
}) => (
  new Promise((resolve, reject) => {

    const APP_NAME              = appName;
    const IP                    = ip.address();
    const HOSTNAME              = hostName;
    const PORT                  = port;
    const EUREKA_HOST           = eurekaHostName;
    const EUREKA_PORT           = eurekaPort;
    const EUREKA_REGISTER       = registerWithEureka;
    const EUREKA_FETCH_REGISTRY = fetchRegistry;

    const eureka = new Eureka({
      instance: {
        app: APP_NAME,
        hostName: IP,
        instanceId: `${HOSTNAME}:${PORT}`,
        ipAddr: IP,
        vipAddress: `${HOSTNAME.toUpperCase()}`,
        statusPageUrl: `http://${HOSTNAME}:${PORT}/actuator/info`,
        healthCheckUrl: `http://${HOSTNAME}:${PORT}/actuator/health`,
        port: {
          $: PORT,
          '@enabled': true
        },
        dataCenterInfo: {
          '@class': 'com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo',
          name: 'MyOwn'
        },
        registerWithEureka: EUREKA_REGISTER,
        fetchRegistry: EUREKA_FETCH_REGISTRY
      },
      eureka: {
        host: EUREKA_HOST,
        port: EUREKA_PORT,
        servicePath: '/eureka/apps/',
        heartbeatInterval: 30000
      }
    });

    eureka.stop = promisify(eureka.stop);

    logger.info('Eureka registry starting...');
    eureka.start(err => {
      if (err) {
        logger.error('Eureka start error', err);
        return reject(null);
      }
      client = eureka;
      resolve(eureka);
    });
  })
);

const deregister = async () => {
  try {
    if (client) {
      logger.info('Eureka deregister...');
      await client.stop();
      client = null;
      
      return true;
    }

    return null;
  }
  catch (err) {
    throw err;
  }
};

const getInstancesByAppId = (appId) => client.getInstancesByAppId(appId);

const getInstancesByVipAddress = (vipAddress) => client.getInstancesByVipAddress(vipAddress);

module.exports = {
  register,
  deregister,
  getInstancesByAppId,
  getInstancesByVipAddress,
  client: () => client
};