express-httpchk

Middleware to provide status endpoint for haproxy.

Example

Add status endpoint in express.

On shutdown start sending 404, then wait for haproxy to report DOWN
before closing.

``javascript

var express = require('express');
var httpchk = require('express-httpchk');

var app = express();


function getStatus(haproxyState) {
return { status: 'OK' };
}

var statusMiddleware = httpchk(getStatus);

app.get('/status', statusMiddleware)

var server = app.listen('3000');

process.on('SIGTERM', function() {
// wait for haproxy to tell us we're out of the lb pool.
statusMiddleware.shutdown()
.then(function () {
server.close();
});
});

`

An appropriate haproxy config. Notice the backend options.

`
global
daemon

defaults
mode http

frontend fe
bind *:80
default_backend be

backend be
option httpchk GET /status
http-check disable-on-404
http-check send-state

server server1 127.0.0.1:3000 check
``