1 files changed, 76 insertions, 0 deletions
diff --git a/lib/gitlab/ci/config/entry/configurable.rb b/lib/gitlab/ci/config/entry/configurable.rb
new file mode 100644
index 00000000000..833ae4a0ff3
--- /dev/null
+++ b/lib/gitlab/ci/config/entry/configurable.rb
@@ -0,0 +1,76 @@
+module Gitlab
+  module Ci
+    class Config
+      module Entry
+        ##
+        # This mixin is responsible for adding DSL, which purpose is to
+        # simplifly process of adding child nodes.
+        #
+        # This can be used only if parent node is a configuration entry that
+        # holds a hash as a configuration value, for example:
+        #
+        # job:
+        #   script: ...
+        #   artifacts: ...
+        #
+        module Configurable
+          extend ActiveSupport::Concern
+          include Validatable
+
+          included do
+            validations do
+              validates :config, type: Hash
+            end
+          end
+
+          def compose!(deps = nil)
+            return unless valid?
+
+            self.class.nodes.each do |key, factory|
+              factory
+                .value(@config[key])
+                .with(key: key, parent: self)
+
+              @entries[key] = factory.create!
+            end
+
+            yield if block_given?
+
+            @entries.each_value do |entry|
+              entry.compose!(deps)
+            end
+          end
+
+          class_methods do
+            def nodes
+              Hash[(@nodes || {}).map { |key, factory| [key, factory.dup] }]
+            end
+
+            private # rubocop:disable Lint/UselessAccessModifier
+
+            def entry(key, entry, metadata)
+              factory = Entry::Factory.new(entry)
+                .with(description: metadata[:description])
+
+              (@nodes ||= {}).merge!(key.to_sym => factory)
+            end
+
+            def helpers(*nodes)
+              nodes.each do |symbol|
+                define_method("#{symbol}_defined?") do
+                  @entries[symbol].specified? if @entries[symbol]
+                end
+
+                define_method("#{symbol}_value") do
+                  return unless @entries[symbol] && @entries[symbol].valid?
+
+                  @entries[symbol].value
+                end
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end