1 files changed, 73 insertions, 0 deletions
diff --git a/lib/gitlab/ci/input/inputs.rb b/lib/gitlab/ci/input/inputs.rb
new file mode 100644
index 00000000000..743ae2ecf1e
--- /dev/null
+++ b/lib/gitlab/ci/input/inputs.rb
@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Ci
+    module Input
+      ##
+      # Inputs::Input class represents user-provided inputs, configured using `with:` keyword.
+      #
+      # Input arguments are only valid with an associated component's inputs specification from component's header.
+      #
+      class Inputs
+        UnknownSpecArgumentError = Class.new(StandardError)
+
+        ARGUMENTS = [
+          Input::Arguments::Required, # Input argument is required
+          Input::Arguments::Default,  # Input argument has a default value
+          Input::Arguments::Options,  # Input argument that needs to be allowlisted
+          Input::Arguments::Unknown   # Input argument has not been recognized
+        ].freeze
+
+        def initialize(spec, args)
+          @spec = spec
+          @args = args
+          @inputs = []
+          @errors = []
+
+          validate!
+          fabricate!
+        end
+
+        def errors
+          @errors + @inputs.flat_map(&:errors)
+        end
+
+        def valid?
+          errors.none?
+        end
+
+        def unknown
+          @args.keys - @spec.keys
+        end
+
+        def count
+          @inputs.count
+        end
+
+        def to_hash
+          @inputs.inject({}) do |hash, argument|
+            raise ArgumentError unless argument.valid?
+
+            hash.merge(argument.to_hash)
+          end
+        end
+
+        private
+
+        def validate!
+          @errors.push("unknown input arguments: #{unknown.inspect}") if unknown.any?
+        end
+
+        def fabricate!
+          @spec.each do |key, spec|
+            argument = ARGUMENTS.find { |klass| klass.matches?(spec) }
+
+            raise UnknownSpecArgumentError if argument.nil?
+
+            @inputs.push(argument.new(key, spec, @args[key]))
+          end
+        end
+      end
+    end
+  end
+end