index.js

require('dotenv').config();
const express = require('express');
const mongoose = require('mongoose');
const routes = require('./routes');
const morgan = require('morgan');
const compression = require('compression');
const swaggerUi = require('swagger-ui-express');
const YAML = require('yamljs');
const DB_CONNECTION = require('./constants/DB_CONNECTION');
const apiDocumentation = YAML.load('./swagger.yml');
const swaggerDocs = require('./swagger');
const { startMetrics, restApiHistogram } = require('./utils/serverMetrics');
const responseTime = require('response-time');
const cors = require('cors');

const app = express();

const run = async () => {
    try {
        await mongoose.connect(DB_CONNECTION, {
            useNewUrlParser: true,
            useUnifiedTopology: true,
        });

        console.log('DB connected successfully');
        /*Middlewares */
        app.use(express.json({ limit: '100mb' }));
        app.use(express.urlencoded({ etended: false }));

        app.use(
            responseTime((req, res, time) => {
                if (req?.route?.path) {
                    restApiHistogram.observe(
                        {
                            method: req.method,
                            route: req.route.path,
                            status_code: res.statusCode,
                        },
                        time * 1000
                    );
                }
            })
        );

        // Application middlewares
        app.use(cors({ origin: '*' }));
        app.use(morgan('dev'));
        app.use(compression());
        app.use('/api', routes);
        app.use(
            '/api-docs',
            swaggerUi.serve,
            swaggerUi.setup(apiDocumentation)
        );

        //
        app.listen(process.env.PORT, () => {
            console.log('Server has started!');
            startMetrics();
            swaggerDocs(app, process.env.PORT);
        });
    } catch (err) {
        console.log(err.message);
        process.exit(1);
    }
};

run().catch((err) => console.log(err.message));

module.exports = app;