ExpressJS configuration for SSL with Let's Encrypt certificates

server.js

'use strict'

const fs = require('fs')
const constants = require('crypto').constants
const spdy = require('spdy')

const server = require('express')
const app = express()
const port = process.env.port || 3000

const srv = spdy.createServer({
        secureOptions: constants.SSL_OP_NO_SSLv2 | constants.SSL_OP_NO_SSLv3 | constants.SSL_OP_NO_TLSv1 | constants.SSL_OP_NO_TLSv1_1,
        key: fs.readFileSync('/etc/letsencrypt/live/monitoring.blauspecht.io/privkey.pem', 'utf-8'),
        cert: fs.readFileSync('/etc/letsencrypt/live/monitoring.blauspecht.io/cert.pem', 'utf-8'),
        spdy: {
            plain: false // do not allow unencrypted traffic
        }
    }, app)

srv.listen(port, () => {
    logger.info('Yup, running on port ' + port)
    logger.info('NODE_ENV = ' + process.env.NODE_ENV)
})