/node
. /config
  . default.js
. node_modules
. /controllers
  . myfile.js
  . other files
. app.js

const express = require('express');
const app = express();
const mysql = require('mysql');
const path = require('path');
const config = require('config');
const bodyParser = require('body-parser');
const moment = require('moment');
app.use(bodyParser.json({type: '*/*'}));
var client;
const redis = require("redis");
client = redis.createClient();

client.on("error", function (err) {
    console.log("Error " + err);
});

const connectionPool = mysql.createPool({
    host: config.get('database.host'),
    user: config.get('database.user'),
    password: config.get('database.password'),
    database: config.get('database.dbname'),
    connectionLimit: 2
});

function selectUpdatedData() {

    connectionPool.query("SELECT * FROM rc_devices_notifications", function (err, rows, fields) {
        //DO STUFF
        process.exit();
    });
}

selectUpdatedData();

WARNING: No configurations found in configuration directory:/home/rc-user/node/controllers/config
WARNING: To disable this warning set SUPPRESS_NO_CONFIG_WARNING in the environment.
/home/rc-user/node/node_modules/config/lib/config.js:181
    throw new Error('Configuration property "' + property + '" is not defined');
    ^

Error: Configuration property "database.host" is not defined
    at Config.get (/home/rc-user/node/node_modules/config/lib/config.js:181:11)
    at Object.<anonymous> (/home/rc-user/node/controllers/update_trackers.js:20:18)
    at Module._compile (module.js:573:32)
    at Object.Module._extensions..js (module.js:582:10)
    at Module.load (module.js:490:32)
    at tryModuleLoad (module.js:449:12)
    at Function.Module._load (module.js:441:3)
    at Module.runMain (module.js:607:10)
    at run (bootstrap_node.js:420:7)
    at startup (bootstrap_node.js:139:9)