Add new GitlabDanger class

This class encapsulates our use of the Danger gem.

1 files changed, 54 insertions, 0 deletions

diff --git a/lib/gitlab_danger.rb b/lib/gitlab_danger.rb
new file mode 100644
index 00000000000..b4768a9546d
--- /dev/null
+++ b/lib/gitlab_danger.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+class GitlabDanger
+  LOCAL_RULES ||= %w[
+    changes_size
+    gemfile
+    documentation
+    frozen_string
+    duplicate_yarn_dependencies
+    prettier
+    eslint
+    database
+  ].freeze
+
+  CI_ONLY_RULES ||= %w[
+    metadata
+    changelog
+    specs
+    commit_messages
+    roulette
+    single_codebase
+    gitlab_ui_wg
+    ce_ee_vue_templates
+    only_documentation
+  ].freeze
+
+  MESSAGE_PREFIX = '==>'.freeze
+
+  attr_reader :gitlab_danger_helper
+
+  def initialize(gitlab_danger_helper)
+    @gitlab_danger_helper = gitlab_danger_helper
+  end
+
+  def self.local_warning_message
+    "#{MESSAGE_PREFIX} Only the following Danger rules can be run locally: #{LOCAL_RULES.join(', ')}"
+  end
+
+  def self.success_message
+    "#{MESSAGE_PREFIX} No Danger rule violations!"
+  end
+
+  def rule_names
+    ci? ? LOCAL_RULES | CI_ONLY_RULES : LOCAL_RULES
+  end
+
+  def html_link(str)
+    self.ci? ? gitlab_danger_helper.html_link(str) : str
+  end
+
+  def ci?
+    !gitlab_danger_helper.nil?
+  end
+end