= engineyard-metadata

Presents a simple, unchanging interface to get metadata about your EngineYard AppCloud instances running on Amazon EC2.

== Purpose

To define an unchanging interface to useful metadata (passwords, IP addresses, etc.) that is otherwise buried deep inside EngineYard's chef config files and various API calls.

== Examples

* Get a dynamically updated list of all running app servers so that you can pool memcached over all of them. (<tt>EY::Metadata.app_servers</tt>)
* Get the current database password so that you can write a script that connects to it. (<tt>EY::Metadata.database_password</tt>)

Get the full method list in {the engineyard-metadata rdoc}[http://rdoc.info/github/seamusabshere/engineyard-metadata].

== Use

=== From the inside

When you're executing the gem from your instances, you don't have to configure anything. Just require the gem.

=== From the outside

You need to provide...

* <tt>ENV['EY_CLOUD_TOKEN']</tt> or have <tt>~/.eyrc</tt>
* <tt>ENV['REPOSITORY_URI']</tt> or execute the gem from the local copy of your application's repo.

=== Where the methods are defined

Metadata getters are defined directly on <tt>EY::Metadata</tt> (which in turn delegates out to various adapters). Even if EngineYard changes the structure of the config files or Amazon EC2's API changes, these methods will stay the same.

  [...]
  >> require 'rubygems'
  [...]
  >> require 'engineyard-metadata'
  [...]
  >> EY::Metadata.database_host
  => "external_db_master.compute-1.amazonaws.com"
  >> EY::Metadata.app_servers
  => [ 'app_1.compute-1.amazonaws.com' , 'app_master.compute-1.amazonaws.com' ]
  >> EY::Metadata.db_servers
  => [ 'db_master.compute-1.amazonaws.com', 'db_slave_1.compute-1.amazonaws.com' ]
  [...and many more...]

== History

This is the second generation of http://rubygems.org/gems/ey_cloud_awareness.

== Copyright

Copyright (c) 2010 Seamus Abshere. See LICENSE for details.