RSpec::StackProf

Provides a convenient way to profile your specs using stackprof gem by integrating stackprof gem with your RSpec setup.

Specs can be profiled at suite level or indvidually.

Installation

Add this line to your application's Gemfile:

gem 'rspec-stackprof'

And then execute:

$ bundle

Or install it yourself as:

$ gem install rspec-stackprof

Usage

Profiling can be enabled by setting environment variable RSPEC_STACKPROF while running rspec command.

  1. To profile the whole test suite, set RSPEC_STACKPROF variable to all while running the command to invoke rspec.

Example:

  RSPEC_STACKPROF=all rspec ...

profiled output is stored in ./tmp/stackprof_<pid>_<timestamp>.out.

  1. To profile each test individually, set RSPEC_STACKPROF environment variable to each

Example:

  RSPEC_STACKPROF=each rspec ..

profiled output is stored individually for each rspec example. A unique filename is constructed by examining spec metadata. A sub directory is created for each 'describe' and 'context' block

For example, given a spec like:

     describe "main context" do 
       ..
       context "primary context" do 
       .. 
         it "does something" do 
         end
       end 
     end

The profiled data will be stored at the following path:

  ./tmp/main_context/primary_context/does_something.<pid>.<timestamp>.out

Configuration

You can configure following parameters for this gem.

  • out_dir

directory location where profile data will be stored. When using RSPEC_STACKPROF=each option, subdirectories will be created under this dir

  • out_file

filename where profile results is stored when using RSPEC_STACKPROF=all option.

In addition, you can configure all Stackprof parameters (mode, interval, 'agregate,raw`) as well.

Add a file spec/support/rspec_stackprof.rb and add/change configuration parameters. For example:

RSpec::StackProf.configure do |config|
  config.out_dir = '/tmp/profiles'
  config.mode = :wall 
  config.interval = 500
end

See stackprof readme to learn about stackprof usage.

Generating Flamegraphs

Set the option raw to true

RSpec::StackProf.configure do |config|
  config.raw = true
end

After profiling, run the following stackprof commands:

stackprof --stackcollapse tmp/stackprof.out > tmp/stackprof_collapsed.out
stackprof-flamegraph.pl tmp/stackprof_collapsed.out > tmp/stackprof_collapsed.svg

Open the svg file in a browser to view the visual representation of your profiled data. Flamegraphs are extremely useful. If you are unfamiliar with flamegraphs, checkout Brendan Gregg's site to learn more about flamegraphs

Development

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.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/rspec-stackprof. 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.