DependencyGrapher

DependencyGrapher is a tool for highlighting certain method calls in your Rails application. Specifically, it highlights cases where classes makes calls to external frameworks that are already being referenced to by service objects. DependencyGrapher tries to use your testing framework to infer method dependencies between classes. It assumes that all service objects are in the `app/services/' folder.

DependencyGrapher will only show classes that are direct neighbours of "known classes". Known classes are inferred from ruby files under Rails.application.config.eager_load_paths. Furthermore, all services are assumed be in the /app/services/folder. A "violation" is when there exists a receiver of a service class that is being called by a non-service class. There edges are shown in red in the resulting graph.

Example: app/controllers/users_controller.rb:

...
  def get_logger
    logger = DependencyGrapher::Logger.new
    logger.enable
    logger.disable
  end
...

app/models/user.rb:

...
  def get_logger
    logger = GetLogger.call
  end
...

app/services/get_logger.rb:

class GetLogger
  def self.call
    DepedencyGrapher::Logger.new
  end
end

user_test.rb:

class UserTest < ActiveSupport::TestCase
  test "dep1" do
    #p "in UserTest the truth"
    @user = users(:tianming)
    @skill = skills(:ruby)
    @user.add_skill(@skill)
    @user.get_logger
    assert @user.has_skill?(@skill)
  end

  test "dep2" do
    #p "in UserTest the truth"
    UsersController.new.get_logger
    assert true
  end
end
  def get_logger
    logger = GetLogger.call
  end

Sample output:

Installation

Add this line to your application's Gemfile:

gem 'dependency_grapher'

And run bundle install.

Usage

In your test helpers file test/test_helper, include DependencyGrapher::TestHelpers to your tests as shown below:

class ActionController::TestCase
  include DependencyGrapher::TestHelpers
  #include DependencyGrapher::TestHelpers
end

class ActiveSupport::TestCase
  include DependencyGrapher::TestHelpers
  # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
  fixtures :all
end

DependencyGrapher requires you first to run your unit tests to produce set of dependencies (outputted to your project folder as dependencies.yml). The parts of your system that are not touched by the tests will not be shown in the graph.

After the tests have complete, run rake dep:graph to produce a svg graph. You may specify the name format of the graph output by using rake dep:graph[name.format]. For example, rake dep:graph[graph.dot] produces a DOT file of the graph. Acceptable formats can be found on the GraphViz site.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/tmzhuang/dependency_grapher. 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.

License

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