text: 
  const DOCKER_DB_URL = 'mongodb://mongo1:27017,mongo2:27018,mongo3:27019';
  const LOCALHOST_DB_URL = 'mongodb://localhost:27017,localhost:27018,localhost:27019';
  const TEST_DB_PATH = '/test';
  const PILOT_DB_PATH = '/pilot';
  const REPLICA_SET = '?replicaSet=my-mongo-set';
  
  let db_url = '';
  if (process.env.IS_DOCKER === 'true') {
    db_url += DOCKER_DB_URL;
  } else {
    db_url += LOCALHOST_DB_URL;
  }
  if (process.env.SERVER_MODE === 'dev') {
    db_url += TEST_DB_PATH;
  } else if (process.env.SERVER_MODE === 'prod') {
    db_url += PILOT_DB_PATH;
  }
  db_url += REPLICA_SET;
  
  module.exports = db_url;