text: const DELAY_TIME = 2000;
  const LIVESTREAM_COUNTER_EXPIRED_TIME = process.env.LIVESTREAM_COUNTER_EXPIRED_TIME || 12 * 60 * 60;
  const FIREBASE_SERVICE_ACCOUNT = process.env.FIREBASE_SERVICE_ACCOUNT || 'app-service-account-firebase.json';
  
  /**
   *
   * @return {string}
   */
  const getKeyFileName = () => {
  	let KEY_FILENAME = `./app-service-account.json`;
  	if (process.env.NODE_ENV === 'production' || process.env.NODE_ENV === 'staging') {
  		KEY_FILENAME = `./${process.env.PATH_SERVICE_ACCOUNT_GCP}`;
  	}
  	return KEY_FILENAME;
  }
  
  const MIN_KEY_FORMAT = 'YYYYMMDDHHmm';
  const SECOND_KEY_FORMAT = 'YYYYMMDDHHmmss';
  
  const DURATION_COUNTING_CCU = process.env.DURATION_COUNTING_CCU || 10;
  const DURATION_MERGE_CCU = process.env.DURATION_MERGE_CCU || 10000;
  
  const CHAT_EVENT = process.env.CHAT_EVENT || 'CHAT_EVENT';
  
  const PUBSUB = {
  	SUBSCRIPTION: {
  		LIVESTREAM_COUNTER_CCU: 'LIVESTREAM_COUNTER_CCU',
  		LIVESTREAM_COMMAND: 'LIVESTREAM_COMMAND'
  	},
  	TOPIC: {
  		VIDEO_WATCHED: 'VIDEO_WATCHED',
  		CHAT_EVENT: 'CHAT_EVENT',
  		SERVICE_NOTIFICATION: 'SERVICE_NOTIFICATION'
  	}
  }
  
  const KEY_LIST_CONTENT = process.env.KEY_LIST_CONTENT || 'list_content';
  
  module.exports = {
  	DELAY_TIME: DELAY_TIME,
  	KEY_FILENAME: getKeyFileName(),
  	LIVESTREAM_COUNTER_EXPIRED_TIME: LIVESTREAM_COUNTER_EXPIRED_TIME,
  	MIN_KEY_FORMAT: MIN_KEY_FORMAT,
  	SECOND_KEY_FORMAT: SECOND_KEY_FORMAT,
  	DURATION_COUNTING_CCU: DURATION_COUNTING_CCU,
  	CHAT_EVENT: CHAT_EVENT,
  	FIREBASE_SERVICE_ACCOUNT: FIREBASE_SERVICE_ACCOUNT,
  	DURATION_MERGE_CCU: DURATION_MERGE_CCU,
  	PUBSUB: PUBSUB,
  	KEY_LIST_CONTENT: KEY_LIST_CONTENT
  }
  