Active Explorer is a Ruby gem for visualization of run-time data and associations represented by Active Record.
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Active Explorer

Active Explorer is a Ruby gem for visualization of run-time data and associations represented by Active Record. It prints your object data with all associated objects in a nice way and with one command.

You can think of it:

  • as "awesome_print with associations" (in console mode) and
  • as "railroady for runtime data" (in image graph version).

NOTE: Only Active Record 4.x and 5.x is supported.

NOTE: This is pre-alpha version. Many things might change.

How the gem works? It simply looks for has_many, has_one and belongs_to associations and traverse through them to associated objects. Then it does the same with them until it explores all the surroundings.

It then prints nice graph represantation:

  • to image file or
  • to console

One picture is worth a thousand words:

Display hierarchy for Author object.

(GraphViz software needs to be installed on the system for this to work. See Graphviz Installation.)

And the same objects in console output:

Author(1592) {:first_name=>"Perer", :last_name=>"Brett"}
  -> has Book(1642) {:author_id=>1592, :title=>"The Warded Man", :year=>2008}
      -> has Review(796) {:stars=>5, :text=>"Very nice book. Life changing experience.", :book_id=>1642}
  -> has Book(1643) {:author_id=>1592, :title=>"The Desert Spear", :year=>2010}


Add this line to your application's Gemfile:

gem 'active_explorer'

And then execute:

$ bundle

Or install it yourself as:

$ gem install active_explorer

Graphviz Installation

You need to have GraphViz software installed on your system.

On Mac: brew install graphviz

On Ubuntu: sudo apt-get install graphviz

On other systems please take a look at official pages or Google for it.


In Rails, place this code into application.rb:

require "active_explorer"


ex my_object # Prints output to console
exf my_object # Prints output as a graph to image file

Note: ex is abbreviation for explore and exf for explore_to_file methods.

See Examples (or test cases) for more examples.



Only exf has:

file_name = nil # When not specified, gem will create file composed of "object class" and "object id", e.g. "book_12.png"

Both ex and exf have:

class_filter: nil,          # Allowed or ignored classes 
attribute_filter: nil,      # Attributes to be displayed (per class setting)
attribute_limit: nil,       # First "n" attributes to be displayed
association_filter: nil,    # Which direction to explore (parents, children, all)?
depth: 5                    # Recursion depth at which to stop


ex Author.first, class_filter: [:books, :reviews],          
               attribute_filter: { books: [:id, :title], reviews: [:id, :text] }, 
               association_filter: [:has_many], 
               attribute_limit: 5,
               depth: 10

Important: Use plural form of your classes.

See Examples (or test cases) see exact usage.

Check Global Configuration to easily set this filter once for all future calls.

Global Configuration

Place this to initializer. E.g. initializers/active_explorer.rb:

ActiveExplorer::Config.class_filter = {ignore: [:reviews]}
ActiveExplorer::Config.attribute_limit = 5
ActiveExplorer::Config.depth = 10

This configuration will be applied for every call of ex or exf as if respective parameters were added to the call.


All examples assume following data and associations:

Author(1) {:first_name=>"Perer", :last_name=>"Brett"}
  -> has Book(1) {:author_id=>1, :title=>"The Warded Man", :year=>2008}
      -> has Review(1) {:stars=>5, :text=>"Very nice book. Life changing experience.", :book_id=>1}
  -> has Book(2) {:author_id=>1, :title=>"The Desert Spear", :year=>2010}

Output to Console

Use ex to print text output to Console.

ex Book.first

Use this in code or in IRB / Rails Console.

Output to Image

Use exf to print output as a nice graph to image file. Following command generates file book_1.png (for Book with id: 1).

exf Book.first

Use this in code or in IRB / Rails Console.

Class Filter


Show only classes that you want.

ex Author.first, class_filter: [:books]

This will only display Author (as a root) and objects of Book class. Processing stops with Book classes and does not go further to parents or children.

Alternative notation using show parameter.

ex Author.first, class_filter: { show: [:books] }


ex Author.first, class_filter: { ignore: [:reviews] }

Attribute Filter

For any class you can specify list of attributes that will be displayed.

ex Author.first, attribute_filter: { books: [:id, :title], reviews: [:id] }

Attribute Limit

Set limit to show just first couple of attributes. This is useful when your classes contain many attributes and final output gets too big (especially image output). When you do not need all attributes to be displayed, this is fastest way to make output much nicer.

ex Author.first, attribute_limit: 3

Association Filter

By default, the gem follows two ways:

  • finds objects associated by belongs_to and continues to look only for belongs_to associations of these objects (recursively for all subobjects)
  • finds objects associated by has_many / has_one and continues to look only for has_many / has_one associations of these objects (recursively for all subobjects)

You can change the default configuration by specifying array containing some of possible values: :has_many, :has_one, :belongs_to, :all.

Value :all means that for each explored object the exploration continues in both has_xxx and belongs_to directions.

ex Book.first, association_filter: [:has_many]

This will explore only the "down" way (through children) of Book object.


After checking out the repo, run bin/setup to install dependencies. Then, run rspec 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


To test support of many different versions I use Appraisal gem that allows me to define several different Gemfiles and test them all at once.

See Appraisals file.


  1. Install gems by calling appraisal install (or appraisal update to update them)
  2. Run tests by calling appraisal rspec (or call specific version appraisal activerecord-4-2 rspec)

Everything should be green ;)


  • Bug hunt.
  • Colorize console output.
  • Export to graphing website.
  • Export to SVG.
  • Export to DOT language.
  • Interactive graph.
  • Rubymine plugin ;)

Known Issues

Timeout in Debugger

When calling exf during debugging session in Rubymine, gem returns timeout error. Apart from this message everything works. The image gets saved and it is saved far before the timeout appears.

It seems that it has something to do with Ruby GraphViz gem.

If you have any hint on this please contact me.


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.


Active Explorer is maintained by


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