gistfile1.txt

      # Get or create an EC2 client and cache that client so that a Context is more well tied together
      # === @params: opts [Hash]
      #      * stub_responses: defaulted to false but it can be overriden with the desired responses for local testing
      #      * region: defaulted to use the `#region()` method
      #      * AWS::Credentials object, which will also scour the context and environment for your keys
      # === @returns: AWS::EC2 client
      # === Sample Usage
      #     ```
      #       config = stub_responses: {
      #         run_instances: {
      #           instances: [
      #             { instance_id: 'asd-1234', launch_time: Time.now, state: { name: 'running' }
      #         ] }
      #         describe_instances: {
      #           reservations: [
      #             { instances: [
      #               { instance_id: 'asd-1234', state: { code: 200, name: 'running' } },
      #           ] }] },
      #         describe_images: {
      #           images: [
      #             { image_id: 'asdf', state: 'available' }
      #         ] }
      #       }
      #
      #       ec2(config) # sets and gets an EC2 client
      #
      #       images = ec2.describe_images
      #       images.first[:image_id]
      #       # => 'asdf'
      #     ```