1 files changed, 122 insertions, 0 deletions
diff --git a/lib/gitlab/audit/type/definition.rb b/lib/gitlab/audit/type/definition.rb
new file mode 100644
index 00000000000..af5dc9f4b44
--- /dev/null
+++ b/lib/gitlab/audit/type/definition.rb
@@ -0,0 +1,122 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Audit
+    module Type
+      class Definition
+        include ActiveModel::Validations
+
+        attr_reader :path
+        attr_reader :attributes
+
+        validate :validate_schema
+        validate :validate_file_name
+
+        InvalidAuditEventTypeError = Class.new(StandardError)
+
+        AUDIT_EVENT_TYPE_SCHEMA_PATH = Rails.root.join('config', 'audit_events', 'types', 'type_schema.json')
+        AUDIT_EVENT_TYPE_SCHEMA = JSONSchemer.schema(AUDIT_EVENT_TYPE_SCHEMA_PATH)
+
+        # The PARAMS in config/audit_events/types/type_schema.json
+        PARAMS = %i[
+          name
+          description
+          introduced_by_issue
+          introduced_by_mr
+          group
+          milestone
+          saved_to_database
+          streamed
+        ].freeze
+
+        PARAMS.each do |param|
+          define_method(param) do
+            attributes[param]
+          end
+        end
+
+        def initialize(path, opts = {})
+          @path = path
+          @attributes = {}
+
+          # assign nil, for all unknown opts
+          PARAMS.each do |param|
+            @attributes[param] = opts[param]
+          end
+        end
+
+        def key
+          name.to_sym
+        end
+
+        private
+
+        def validate_schema
+          schema_errors = AUDIT_EVENT_TYPE_SCHEMA
+                            .validate(attributes.to_h.deep_stringify_keys)
+                            .map { |error| JSONSchemer::Errors.pretty(error) }
+
+          errors.add(:base, schema_errors) if schema_errors.present?
+        end
+
+        def validate_file_name
+          # ignoring Style/GuardClause because if we move this into one line, we cause Layout/LineLength errors
+          # rubocop:disable Style/GuardClause
+          unless File.basename(path, ".yml") == name
+            errors.add(:base, "Audit event type '#{name}' has an invalid path: '#{path}'. " \
+              "'#{name}' must match the filename")
+          end
+          # rubocop:enable Style/GuardClause
+        end
+
+        class << self
+          def paths
+            @paths ||= [Rails.root.join('config', 'audit_events', 'types', '*.yml')]
+          end
+
+          def definitions
+            # We lazily load all definitions
+            @definitions ||= load_all!
+          end
+
+          def get(key)
+            definitions[key.to_sym]
+          end
+
+          private
+
+          def load_all!
+            paths.each_with_object({}) do |glob_path, definitions|
+              load_all_from_path!(definitions, glob_path)
+            end
+          end
+
+          def load_all_from_path!(definitions, glob_path)
+            Dir.glob(glob_path).each do |path|
+              definition = load_from_file(path)
+
+              if previous = definitions[definition.key]
+                raise InvalidAuditEventTypeError, "Audit event type '#{definition.key}' " \
+                  "is already defined in '#{previous.path}'"
+              end
+
+              definitions[definition.key] = definition
+            end
+          end
+
+          def load_from_file(path)
+            definition = File.read(path)
+            definition = YAML.safe_load(definition)
+            definition.deep_symbolize_keys!
+
+            new(path, definition).tap(&:validate!)
+          rescue StandardError => e
+            raise InvalidAuditEventTypeError, "Invalid definition for `#{path}`: #{e.message}"
+          end
+        end
+      end
+    end
+  end
+end
+
+Gitlab::Audit::Type::Definition.prepend_mod