Create rake task for docs CODEOWNERS

Creates a rake task that grabs the names of all markdown files in
the doc/ directory, parses the front matter in each file, and prints
formatted strings including the filename and the technical writer
associated with the group specified in the metadata.

lib/tasks/gitlab/tw/codeowners.rake

+# frozen_string_literal: true
+
+require 'yaml'
+
+namespace :tw do
+  desc 'Generates a list of codeowners for documentation pages.'
+  task :codeowners do
+    CodeOwnerRule = Struct.new(:category, :writer)
+
+    CODE_OWNER_RULES = [
+      CodeOwnerRule.new('Activation', '@kpaizee'),
+      CodeOwnerRule.new("Adoption", '@kpaizee'),
+      CodeOwnerRule.new('Activation', '@kpaizee'),
+      CodeOwnerRule.new('Adoption', '@kpaizee'),
+      CodeOwnerRule.new('APM', '@ngaskill'),
+      CodeOwnerRule.new('Authentication & Authorization', '@eread'),
+      CodeOwnerRule.new('Certify', '@msedlakjakubowski'),
+      CodeOwnerRule.new('Code Review', '@aqualls'),
+      CodeOwnerRule.new('Compliance', '@eread'),
+      CodeOwnerRule.new('Composition Analysis', '@rdickenson'),
+      CodeOwnerRule.new('Configure', '@marcia'),
+      CodeOwnerRule.new('Container Security', '@ngaskill'),
+      CodeOwnerRule.new('Contributor Experience', '@eread'),
+      CodeOwnerRule.new('Conversion', '@kpaizee'),
+      CodeOwnerRule.new('Database', '@marcia'),
+      CodeOwnerRule.new('Development', '@marcia'),
+      CodeOwnerRule.new('Distribution', '@axil'),
+      CodeOwnerRule.new('Distribution (Charts)', '@axil'),
+      CodeOwnerRule.new('Distribution (Omnibus)', '@axil'),
+      CodeOwnerRule.new('Documentation Guidelines', '@cnorris'),
+      CodeOwnerRule.new('Dynamic Analysis', '@rdickenson'),
+      CodeOwnerRule.new('Ecosystem', '@kpaizee'),
+      CodeOwnerRule.new('Editor', '@aqualls'),
+      CodeOwnerRule.new('Expansion', '@kpaizee'),
+      CodeOwnerRule.new('Foundations', '@rdickenson'),
+      CodeOwnerRule.new('Fuzz Testing', '@rdickenson'),
+      CodeOwnerRule.new('Geo', '@axil'),
+      CodeOwnerRule.new('Gitaly', '@eread'),
+      CodeOwnerRule.new('Global Search', '@marcia'),
+      CodeOwnerRule.new('Health', '@ngaskill'),
+      CodeOwnerRule.new('Import', '@ngaskill'),
+      CodeOwnerRule.new('Infrastructure', '@marcia'),
+      CodeOwnerRule.new('Integrations', '@kpaizee'),
+      CodeOwnerRule.new('Knowledge', '@aqualls'),
+      CodeOwnerRule.new('License', '@sselhorn'),
+      CodeOwnerRule.new('Memory', '@marcia'),
+      CodeOwnerRule.new('Monitor', '@ngaskill'),
+      CodeOwnerRule.new('Optimize', '@fneill'),
+      CodeOwnerRule.new('Package', '@ngaskill'),
+      CodeOwnerRule.new('Pipeline Authoring', '@marcel.amirault'),
+      CodeOwnerRule.new('Pipeline Execution', '@marcel.amirault'),
+      CodeOwnerRule.new('Portfolio Management', '@msedlakjakubowski'),
+      CodeOwnerRule.new('Product Intelligence', '@fneill'),
+      CodeOwnerRule.new('Product Planning', '@msedlakjakubowski'),
+      CodeOwnerRule.new('Project Management', '@msedlakjakubowski'),
+      CodeOwnerRule.new('Provision', '@sselhorn'),
+      CodeOwnerRule.new('Purchase', '@sselhorn'),
+      CodeOwnerRule.new('Redirect', 'Redirect'),
+      CodeOwnerRule.new('Release', '@rdickenson'),
+      CodeOwnerRule.new('Runner', '@sselhorn'),
+      CodeOwnerRule.new('Sharding', '@marcia'),
+      CodeOwnerRule.new('Source Code', '@aqualls'),
+      CodeOwnerRule.new('Static Analysis', '@rdickenson'),
+      CodeOwnerRule.new('Static Site Editor', '@aqualls'),
+      CodeOwnerRule.new('Style Guide', '@sselhorn'),
+      CodeOwnerRule.new('Testing', '@eread'),
+      CodeOwnerRule.new('Threat Insights', '@fneill'),
+      CodeOwnerRule.new('Utilization', '@sselhorn'),
+      CodeOwnerRule.new('Vulnerability Research', '@fneill'),
+      CodeOwnerRule.new('Workspace', '@fneill')
+    ].freeze
+
+    Document = Struct.new(:group, :redirect) do
+      def has_a_valid_group?
+        group && !redirect
+      end
+
+      def missing_metadata?
+        !group && !redirect
+      end
+    end
+
+    def self.writer_for_group(category)
+      CODE_OWNER_RULES.find { |rule| rule.category == category }&.writer
+    end
+
+    errors = []
+
+    path = Rails.root.join("doc/**/*.md")
+    Dir.glob(path) do |file|
+      yaml_data = YAML.load_file(file)
+      document = Document.new(yaml_data['group'], yaml_data['redirect_to'])
+
+      if document.missing_metadata?
+        errors << file
+        next
+      end
+
+      writer = writer_for_group(document.group)
+      next unless writer
+
+      puts "#{file.gsub(Dir.pwd, ".")} #{writer}" if document.has_a_valid_group?
+    end
+
+    if errors.present?
+      puts "-----"
+      puts "ERRORS - the following files are missing the correct metadata:"
+      errors.map { |file| puts file.gsub(Dir.pwd, ".")}
+    end
+  end
+end