Ruby Flog Flay Setup

Overview

Install flog/flay Rake tasks with env-configurable thresholds and a pre-commit hook that runs bundle exec rake .

Workflow

1. Inspect existing setup

• Check Gemfile for flog and flay entries.

• Search for existing :flog or :flay rake tasks in Rakefile and rakelib/ to avoid duplicates.

• Check git config core.hooksPath to determine the hooks directory (default is .git/hooks when unset).

2. Ensure dependencies

• Add gem "flay" and gem "flog" to Gemfile if missing (no version pinning).

• Run bundle install if needed.

3. Define tasks in Rakefile

• Define :flog and :flay tasks directly in Rakefile .

• Use env-configurable thresholds with defaults.

• Use bundle exec for both tools.

• Log only on failure using puts and exit non-zero; stay silent on success.

• Do not filter out any files or paths.

• Allow flay duplication when Total score <= FLAY_THRESHOLD .

Example task definitions:

desc "Run flog" task :flog do output = bundle exec flog -a lib threshold = (ENV["FLOG_THRESHOLD"] || 25).to_i method_scores = []

output.each_line do |line| if line =~ /^\s*(\d+.\d+):\s+(.+#.+)\s+(.+.rb)/ score = $1.to_f method_name = $2.strip file_path = $3.strip method_scores << [score, "#{method_name} #{file_path}"] end end

failing_methods = method_scores.select { |score, _| score > threshold } if failing_methods.any? puts "\nFlog failed: Methods with complexity score > #{threshold}:" failing_methods.each { |score, method_name| puts " #{score}: #{method_name}" } exit 1 end end

desc "Run flay" task :flay do output = bundle exec flay lib threshold = (ENV["FLAY_THRESHOLD"] || 0).to_i

if (match = output.match(/Total score (lower is better) = (\d+)/)) score = match[1].to_i if score > threshold puts "\nFlay failed: Total duplication score is #{score}, must be <= #{threshold}" puts output exit 1 end end end

• Remove or update any conflicting :flog /:flay tasks in rakelib/ to avoid duplicate definitions.

• Ensure the default task includes flog and flay if the project expects them to run in CI.

4. Install pre-commit hook

• Create or update pre-commit in the hooks directory from core.hooksPath (or .git/hooks ).

• Use bash and run bundle exec rake unconditionally.

• Exit non-zero if rake fails.

Example hook:

#!/usr/bin/env bash bundle exec rake result=$? if [ $result -ne 0 ]; then echo "bundle exec rake failed. Commit aborted." exit $result fi

• Ensure the hook is executable.

5. Verify

• Run bundle exec rake and confirm it succeeds.

• Make a test commit if needed to confirm the hook blocks failing builds.