Sample Node app using knex.js with postgres. Used to test the active connections on an Azure Web App.

app.js

//set DEBUG=knex* to get more info

let activeConnections = 0;

const knexSettings = {
    client: 'pg',
    pool: {
        min: 2,
        max: 10,
        afterCreate: function (conn, done) {
            console.log(`New DB Connection! active connections: ${++activeConnections}`);
            done(null, conn);
        },
        beforeDestroy: function (conn, done) {
            console.log(`DB Connection Released! active connections: ${--activeConnections}`);
            done(null, conn);
        },
    },
    connection: 'postgres://localhost/some_db'//process.env.POSTGRESQLCONNSTR_DB
}

const port = 3000; //process.env.PORT

const knex = require('knex')(knexSettings);

const healthcheck = require('healthcheck-middleware')({
    addChecks: function(fail, pass) {
        knex.raw('SELECT 1=1;')
        .then(function() {
            console.log('query was successful');
            pass();
        })
        .catch(function(err) {
            console.error('query wasn\'t successful');
            console.error(err);
            fail(new Error('could not connect to database'));
        })
    }
});

const server = require('express')();

server.use('/', healthcheck);

server.listen(port);

console.log(`Server running on port ${port}`);

package.json

{
  "name": "knex-postgres-sample",
  "version": "0.0.1",
  "description": "",
  "main": "app.js",
  "engines": {
    "node": "8.4.0",
    "npm": "4.2.0"
  },
  "dependencies": {
    "express": "^4.12.3",
    "healthcheck-middleware": "^1.0.1",
    "knex": "^0.14.6",
    "pg": "^7.4.1"
  },
  "devDependencies": {},
  "scripts": {
    "start": "node app.js"
  }
}