A playful scm mirror platform for MSR (mining software repositories)

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What this is

Frisky is an engine to cache and process SCM repositories, supporting initially Git and particularly Github as a discovery source.

How it works

Frisky allows you to create classifiers that mine information from software repositories, handling the specifics of data gathering, caching and storage. Classifiers can interact with each others' data by consuming and setting objects' tags.

Classifiers are Ruby classes that respond to mining events.

class CommitCountClassifier < Classifier
  commit :update_commit_count, if: lambda {|commit| commit.files_type('Ruby').any? }

  def update_file_loc(commit)
    @repository.increment(:commit_count, 1)

The commit class method specifies a callback method that will be called whenever a new commit that contains at least one file of Ruby code.

A more useful classifier

The following classifier will run reek on ruby files on each commit, gathering the results on each commit object to get a clear picture of the evolution of code smells on each commit.

We also want to persist this information to the committer responsible for the delta so we can find out how each user has performed over time.

class ReekClassifier < Classifier
  commit :run_reek_on_commit

  def run_reek_on_commit(commit)
    commit.file_types 'Ruby' do |file|
      # Only get reek when we have something to compare against
      next unless commit.parent

      reek_v2 = file_reek_on, file
      reek_v1 = file_reek_on, file
      reek_delta = reek_v2 - reek_v1

      commit.increment(:reek, reek_delta), reek_delta)

  def file_reek_on(commit_id, file_path)
    cached_output :reek, commit_id, file_path

  # Get reek output for an IO
  def output_reek(io)
    # ...

Here the method file_reek_on is called to gather the reek score of each file on each commit, gathering the score of the parent of that file and storing the delta associated to the commit and to the author.

The method cached_output will call output_reek only when the score hasn't been generated previously.


Frisky's architecture is composed of schedulers and classifiers.

Infrastructure requirements

Frisky requires the following software stack to run

  • mongodb >= 2.2
  • redis >= 1.4
  • ruby 1.9


A simple clone will do:

git clone
cd frisky
bundle install


The main configuration file is frisky.yml

    - client_id:client_secret
mongo: mongodb://

The configuration is self-explanatory, the only thing that needs clarification is the github.keys key, the key is an array of client_id:client_secret duples, on startup frisky will pick a random key and use it throughout the session.


bundle exec bin/frisky-event-scheduler -v

Fetches github public events and caches them for further processing. Can be run in parallel in multiple hosts.

bundle exec bin/frisky-classifiers -v

Loads classifiers models and processes events through them. Can be run in parallel in multiple hosts.