Mulder

A deploy-time helper for your AWS AutoScaling groups, and servers. Discover the IP addresses of your instances by AutoScalingGroup.

Installation

Add this line to your application's Gemfile:

gem 'mulder'

And then execute:

$ bundle

Or install it yourself as:

$ gem install mulder

Usage

CLI

To see the web servers for an app, and environment:

mulder search banana_sandwich production WebServerGroup

Example output:

[
    {
                    :id => "i-ididid",
              :dns_name => "web.prod.example.com",
     :public_ip_address => "1.0.1.0",
    :private_ip_address => "0.1.0.1",
     :availability_zone => "us-east-1a",
            :created_at => 2013-08-08 18:21:05 UTC
    }
]

To change the configration file:

mulder search banana_sandwich production WebServerGroup human foo.yml

Capistrano

At the top of your deploy.rb file, add:

require 'mulder/capistrano'

Configure some variables for later use:

set :application, 'banana_sandwich'
set :environment, 'production'
set :aws_creds,   '/foo/config/aws.yml'
set :mulder,      { Mulder::Capistrano.new(aws_creds, environment, application) }

Setting up your worker role:

role :worker, *mulder.ips('WorkerServerGroup')

And your app role:

role(:app, *mulder.ips('AppServerGroup')

And your web role:

role :web, *mulder.ips('WebServerGroup')

And your db role:

role :db, mulder.ips('WorkerServerGroup').first, primary: true

You can ask for private IPs as well:

role :app, *mulder.ips('WorkerServerGroup', true)

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request