Swirl

Swirl is an EC2 version agnostic client for EC2 writtin in Ruby. It gets out of your way.

The secret is it's simple input extraction and output compacting. Your input parameters and expanded and EC2's (terrible) xml output is compacted.

Some simple examples:

# Input
{ "InstanceId" => ["i-123k2h1", "i-0234d3"] }

is expanded to:

{ "InstanceId.0" => "i-123k2h1", "InstanceId.1" => "i-0234d3" }

in the case that .n isn't at the end of the key:

{ "Foo.#.Bar" => ["a", "b"] }

is expanded to:

{ "Foo.0.Bar" => "a", "Foo.1.Bar" => "b" }

and

# Output
{
  "reservationSet" => {
    "item" => {
      "instancesSet" => { "item" => [ ... ] }
    }
  }
}

and it's varations are now compacted to:

{ "reservationSet" => { "instancesSet" => [ { ... }, { ... } ] } }

Some things worth noteing is that compact ignores Symbols. This allows you to pass the params into call and use them later without affecting the API call (i.e. chain of responsiblity); a nifty trick we use in (Rack)[http://github.com/rack/rack]

Use

ec2 = Swirl::EC2.new

# Describe all instances
ec2.call "DescribeInstances"

# Describe specific instances
ec2.call "DescribeInstances", "InstanceId" => ["i-38hdk2f", "i-93nndch"]

Shell

$ swirl
>> c
<Swirl::EC2 ... >
>> c.call "DescribeInstances"
...

The shell respects your ~/.swirl file for configuration