TraceGraph

TraceGraph gives you visibility into the control flow of your application. Rather than read all the code trying to form a mental picture of it, let TraceGraph draw you a picture like this:

Or it can generate a text based graph, like this:

trace
└─DocumentGenerationWorker#perform
  └─DocumentGenerator#generate_and_store_documents
    └─OutputGenerationWorker#perform
      └─OutputGenerator#generate_and_store_output
        ├─OutputOwnerUtils#current_output
        │ └─OutputOwnerUtils#current_outputs
        ├─OutputGenerator#find_creator
        ├─OutputUtils#local_path
        │ └─Output#local_file_prefix
        ├─Output#s3_path
        │ └─OutputUtils#s3_filename
        └─OutputGenerator#generate_and_store_output_implementation
          ├─OutputUtils#markdown_path
          │ └─Output#local_file_prefix (#2)
          ├─OutputGenerator#generate_output
          │ ├─Style#template_variable_hash
          │ │ ├─Style#template_variables
          │ │ └─Style#template
          │ ├─Document#importurlsupported
          │ ├─Account#current_subscription
          │ │ └─Account#active_subscriptions
          │ ├─Account#current_subscription (#2)
          │ │ └─Account#active_subscriptions (#2)
          │ ├─OutputUtils#markdown_path (#2)
          │ │ └─Output#local_file_prefix (#3)
          │ └─PdfCreator#create_pdf
          │   ├─PdfCreator#localize_images
          │   │ └─PdfCreator#find_image_tags_and_urls
          │   ├─PdfCreator#process_liquid
          │   ├─LatexHelper#make_dollars_safe
          │   └─PdfCreator#build_pandoc_string
          │     ├─PdfCreator#merged_variable_options
          │     ├─PdfCreator#class_options
          │     └─PdfCreator#add_pandoc_options
          └─OutputGenerator#notify_output
            └─PusherOutputNotifier#notify_output
              └─Account#pusher_channel

Add this line to your application's Gemfile:

gem 'trace_graph', group: [:development, :test]

And then execute:

$ bundle

Or install it yourself as:

$ gem install trace_graph

A simple use might look like this:

foo = Foo.new
tracer = TraceGraph::Tracer.new({ included_paths: ["foo"], png: 'foo_trace.png' })
tracer.trace{ foo.foo_both }

For the Foo class shown below you'd see output like this in your console:

trace
└─Foo#foo_both
  ├─Foo#first_method
  └─Foo#second_method

And a graph like this would be generated at foo_trace.png

# foo.rb
class Foo
  def first_method
  end

  def second_method
  end

  def foo_both
    first_method
    second_method
  end
end

When constructing a tracer you can pass in a number of options to control what shows up in the graph.

• included_paths - By default TraceGraph will not capture any lines, so you need to tell it what files you're interested in. If your app lives in a directory called my_app and you want to see everything in your app you could pass ["my_app"]. You can include as many paths as you need in the array. Default value is an empty array. If you weant to see everythin you can pass nil. (For something like a Rails app you probably really don't want to see everything.)

• excluded_paths - A list of paths to exclude. Maybe ["my_app/some_utility_helper"]. Default value is nil.

• png - A string path where to write a png graph. If no value is passed a png will not be generated and only a text representation will be written to standar out.

• mark_duplicate_calls - Either true or false. Default value is false. When true any repeat calls to a method will be marked with a count, and will be colored red on the png.

• show_arguments - Either true or false. Default value is false. When true the arguments passed to each method call will be shown. (This doesn't work so well if there are lots of arguments or some very large ones...)

• show_return_values - Either true or false. Default value is false. When true the return values from each method call will be shown. (This doesn't work so well for lots or large return values.)

A robust tracer might look like this:

tracer = TraceGraph::Tracer.new({
  included_paths: ["my_app/app", "my_app/lib"], # See everything local to a rails app
  excluded_paths: ["my_app/app/helpers"],       # Except the helpers
  mark_duplicate_calls: true,
  show_arguments: true,
  show_return_values: true,
  png: 'my_very_busy_trace.png'
})

TraceGraph uses the ruby TracePoint class, and paths are matched on the inspect value for a trace. A typical inspect values looks like this:

#<TracePoint:call `first_method'@/Users/jgreen/projects/trace_graph/spec/support/foo.rb:2>

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 rubygems.org.

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

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