RShade

RShade is a debugging/code exploration tool based on TracePoint functionality. Recent years I've working with relatively huge legacy code and I need a tool which can help me to figure out what is going on due execution. Luckely Ruby have build in functionality to achieve it, but it's pretty low level. It was my motivation to create RShade it helps me to save tons of time when I face with something not trivial or a good start point to create dependency map when I do refactoring or bugfix. Tool still in beta and it's possible that there is some bugs, but it's do the job.

gem install rshade

Simple wrap code that you want to check in to block and it will pretty print all of the calls which was made in this block with pointing line of executions, variables what was pass inside methods and variables what was return

RShade::Trace.reveal do  
  #your code here
end.show

Due that tool create a detailed log with all of the steps of execution it's hard to read (it's can easelly be 20 - 30k lines because it's shows not only your custom code but also code in gems that are involved in execution). RShade have filters to tackle this problem. Default filter is illiminate all code related to gems and only expose app code itself. You can change this behaviour or add your own filter. Even when some piece of code are not shown due filtration order of calls and execution still shown in correct way.

• Configuration
• Filters
  • Filter by path include
  • Filter by path exclude
  • Filter by variable name or value
• Examples

config = ::RShade::Config.default

RShade::Trace.reveal(config) do
end.show

Filters by default represent by expression (include_path or variable_match) or (not exclude_path) Filters can be chained like:

config = ::RShade::Config.default.include_paths { |paths| paths << /devise/ }
                                  .exclude_paths { |paths| paths << /warden/ } 
                                  .match_variable { |name, value| name == :current_user }

paths - is array which accept regex or string

config = ::RShade::Config.default.include_paths { |paths| paths << /devise/ }

RShade::Trace.reveal(config) do
   #your code
end.show

paths - is array which accept regex or string

config = ::RShade::Config.default.exclude_paths { |paths| paths << /devise/ }

RShade::Trace.reveal(config) do
   #your code
end.show

name - represent variable name as symbol value - actual variable value

config = ::RShade::Config.default.match_variable { |name, value| name == :current_user }

RShade::Trace.reveal(config) do
   #your code
end.show

I've took example from https://github.com/spree/spree code base. Wrap code to take a look what code is in use when you save variant. On such huge codebase as spree it's helpful to know what callbacks are triggered and so on.

  context '#cost_currency' do
    context 'when cost currency is nil' do
      before { variant.cost_currency = nil }

      it 'populates cost currency with the default value on save' do
         RShade::Trace.reveal do
          variant.save!
        end
        expect(variant.cost_currency).to eql 'USD'
      end
    end
  end

Below is example how output will look like. As you can see all code that have been in use is printed.

Use stack to keep connections between current method and caller
take a look on https://github.com/matugm/visual-call-graph

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

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