diff_environment.rb

require 'chef/knife'

module Chef
  module Knife
    class DiffEnvironment < Chef::Knife

      banner 'knife diff environment ENVIRONMENT_FILE'

      deps do
        require 'chef/environment'
        require 'chef/knife/core/object_loader'
        require 'chef/json_compat'
        require 'knife_neat/diff'
      end

      def run
        file = name_args.first

        unless file
          show_usage
          ui.fatal('You must specify an environment name')
          ui.fatal("ex: #{$0} diff environment chef/environments/development.rb")
          exit 1
        end

        unless File.exist?(file)
          ui.fatal("Environment file #{file} could not be found")
          exit 1
        end

        loader = Chef::Knife::Core::ObjectLoader.new(Chef::Environment, ui)
        local_env = loader.load_from('environments', file)
        local_result = Chef::JSONCompat.to_json_pretty(local_env)

        env_name = local_env.name

        if env_name.empty?
          ui.fatal("Environment file #{file} must contain a name")
          exit 1
        end

        chef_env = Chef::Environment.load(env_name)
        chef_result = Chef::JSONCompat.to_json_pretty(chef_env)

        ui.info "Comparison of '#{env_name}' environment from #{server_url} (---) with local file '#{file}' (+++):"
        diff = KnifeNeat::Diff.diff(chef_result, local_result)

        ui.info(diff)
      end
    end
  end
end