1 files changed, 49 insertions, 0 deletions
diff --git a/lib/gitlab/ci/config/external/mapper/variables_expander.rb b/lib/gitlab/ci/config/external/mapper/variables_expander.rb
new file mode 100644
index 00000000000..fddf04984d8
--- /dev/null
+++ b/lib/gitlab/ci/config/external/mapper/variables_expander.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Ci
+    class Config
+      module External
+        class Mapper
+          # Handles variable expansion
+          class VariablesExpander < Base
+            def expand(data)
+              if data.is_a?(String)
+                expand_variable(data)
+              else
+                transform_and_expand_variable(data)
+              end
+            end
+
+            private
+
+            def process_without_instrumentation(locations)
+              locations.map { |location| expand(location) }
+            end
+
+            def transform_and_expand_variable(data)
+              data.transform_values do |values|
+                case values
+                when Array
+                  values.map { |value| expand_variable(value.to_s) }
+                when String
+                  expand_variable(values)
+                else
+                  values
+                end
+              end
+            end
+
+            def expand_variable(data)
+              ExpandVariables.expand(data, -> { variables })
+            end
+
+            def variables
+              @variables ||= context.variables_hash
+            end
+          end
+        end
+      end
+    end
+  end
+end