Peeky is a Ruby GEM for peaking into ruby classes and extracting meta

When using the source code for this gem, start by running bin/setup to install locally or bundle install


Add this line to your application's Gemfile:

gem 'peeky'

And then execute:

bundle install

Or install it yourself as:

gem install peeky


Main Story

As a Ruby Developer, I should be able to Reverse engineer classes and methods, so that I can document and understand them

See all stories

  • As a Developer, I should be able to interrogate class instance information, so that I can reverse engineer a ruby class
  • As a Developer, I can render a method with minimal parameter calls, So that I know the minimum parameters when calling a method
  • As a Developer, I can render a class with instance attributes and methods, So that I can quickly mock out an entire class


See all usage examples

Basic Example

This example assumes you have this simple class

module Sample
  class SimpleClass
    attr_accessor :read_write

    def position_and_optional(aaa, bbb = 1)

Rendering Examples

Here a list of example renderers for the simple class

Class interface

Render simple class using class_interface renderer with compact formatting

puts api.render_class(:class_interface, instance:
class SimpleClass
  attr_accessor :read_write

  def position_and_optional(aaa, bbb = nil);                                      end

Documented class interface

Render simple class using class_interface_yard renderer to product YARD compatible documentation

puts api.render_class(:class_interface_yard, instance:
class SimpleClass
  # Read write
  attr_accessor :read_write

  # Position and optional
  # @param aaa [String] aaa (required)
  # @param bbb [String] bbb (optional)
  def position_and_optional(aaa, bbb = nil)

Class debug

Render debug information

puts api.render_class(:class_debug, instance:
class name                    : SimpleClass
module name                   : Sample
class full name               : Sample::SimpleClass

-- Attributes --------------------------------------------------------
attr_accessor                 : read_write

-- Public Methods ----------------------------------------------------
name                 param format         type
aaa                  aaa                  param_required
bbb                  bbb = nil            param_optional


After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to


Bug reports and pull requests are welcome on GitHub at This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.


The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Peeky project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.

Copyright (c) David. See MIT License for further details.