SkyBoot

Helper library for starting up and configuring apps with SkyDNS and Etcd.

Methods

skyboot.init(config, callback);

Initializes the config. Once everything has been set up it runs callback. Everything that depends on the config should be run inside that callback.

skyboot.getSrv(service, cb(err, record) );

Looks up the DNS SRV record and returns a random service from the list of services.

record will be in the form:

{ host: 'hostname.service.skydns.local', port: 8080}

skyboot.config(key)

Access the config object with the optional key:

skyboot.log()

Get the log object.

Config Explanation

SkyBoot expands values that begin with etcd: or srv: into the values received from the etcd or the DNS srv records.

For example:

{
  etcd_service: 'etcd-4001.skydns.local',
  db: {
    server: 'srv:redis.skydns.local'
    password: 'etcd:/services/db/password'
  }
}

Will be expanded to:

{
  etcd_service: 'etcd-4001.skydns.local',
  db: {
    server: { host: 'redis1.redis.skydns.local', port: 1337 }
    password: 'mysuperpass'
  }
}

Special Keys

etcd_service: ""

Defines a DNS SRV record to look up etcd servers. The results will then override etcd_hosts.

etcd_hosts: []

A list of etcd servers in the format 'host:port'.

If etcd_hosts and etcd_service are empty etcd: config values will not expand but initialization will complete.

srv_records: {}

Custom prefilling of dns lookup results for config expansion and getSrv().

This is mostly useful for local development that might not have access to the right DNS and when controlled results are required from config expansion and getSrv().

log: SimpleLogger

Set a logging object. This object will be used by SkyBoot for messages.

Quick Example

Simple standalone example:

var http = require('http');
var request = require('request');
var skyboot = require('skyboot');
var mqtt = require('mqtt');
var config_template = {
  etcd_service: 'etcd-4001.skydns.local',
  mqtt: 'srv:mqtt.skynds.local',
  port: 'etcd:/apps/myservice/port',
  github: { api_key: 'etcd:/apps/github/api_key' }
};

skyboot.init(config_template, function () {
  var mqtt_config = skyboot.config('mqtt');
  mqtt.connect(mqtt_config.port, mqtt_config.host);
  var server = http.createServer().listen(skyboot.config().port);
  skyboot.getSRV('metrics.skynds.local', function (err, service) {
    var url = ['http://', service.host, ':', service.port, '/announce/server_start'].join();
    request.post(url, { listening: 'myserver', port: skyboot.config().port });
  });
});

Works wonderfully with other boot phase libs like bootable or onboot:

var onboot = require('onboot');
var skyboot = require('skyboot');

onboot.strap(function (done) {
  var config_template = {
    etcd_service: 'etcd-4001.skydns.local',
    mqtt: 'srv:mqtt.skynds.local',
    port: 'etcd:/apps/myservice/port'
  };
  skyboot.init(config_template, done);
})
onboot.strap(function (done) {
  // Do other async pre stuff
});

onboot.up(function () {
  mqtt.connect(skyboot.config().mqtt.port, skyboot.config().mqtt.host);
  // ... Do all your stuff like starting a http server listener
});