Docker Rainbow-dns Polulator

dnspop.js

#!/usr/bin/env node
var request    = require('request')
var Docker     = require('dockerode')
var swarm      = Docker({host: 'http://docker.host', port: 4243})
var dnshost    = 'http://dns.host:8080'
var interval   = 2000

var loop = function () {
    getContainers(function (currContainer) {
        updateDns(currContainer)
    })
}

var getContainers = function (callback) {
    var currContainers = {}
    swarm.listContainers(function (err, containers) {
        if (!containers) { console.error("ERROR: Unable to query containers"); return }
        var calls = 0, evalEnd = function () { calls++; if (calls == containers.length) callback(currContainers) }
        containers.forEach(function (container, index) {
            var c = swarm.getContainer(container.Id)
            c.inspect(function (err, data) {
                currContainers[container.Id] = data
                evalEnd(index)
            })
        })
    })
}

var updateDns = function (containers, callback) {
    Object.keys(containers).forEach(function (id) {
        var group = containers[id].Config.Image
        if (group.indexOf('/') > 0) group = group.split('/')[1]
        var name = containers[id].Name + '.' +group;
        name = name.replace(':','.')
        request({
            url     : dnshost+name,
            method  : 'PUT',
            json    : true,
            body    : { A : [{address:containers[id].NetworkSettings.IPAddress}] },
            timeout : interval / 2
        }, function (err, res) {
            if (err) { console.error('ERROR: Unable to update DNS', err.code); return }
            if (res.statusCode != 200) console.log(res.statusCode)
        })
    })
}

loop()
setInterval(loop, interval)