3 files changed, 154 insertions, 0 deletions
diff --git a/lib/gitlab/ci/config/entry/product/matrix.rb b/lib/gitlab/ci/config/entry/product/matrix.rb
new file mode 100644
index 00000000000..6af809d46c1
--- /dev/null
+++ b/lib/gitlab/ci/config/entry/product/matrix.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Ci
+    class Config
+      module Entry
+        ##
+        # Entry that represents matrix style parallel builds.
+        #
+        module Product
+          class Matrix < ::Gitlab::Config::Entry::Node
+            include ::Gitlab::Utils::StrongMemoize
+            include ::Gitlab::Config::Entry::Validatable
+            include ::Gitlab::Config::Entry::Attributable
+
+            validations do
+              validates :config, array_of_hashes: true
+
+              validate on: :composed do
+                limit = Entry::Product::Parallel::PARALLEL_LIMIT
+
+                if number_of_generated_jobs > limit
+                  errors.add(:config, "generates too many jobs (maximum is #{limit})")
+                end
+              end
+            end
+
+            def compose!(deps = nil)
+              super(deps) do
+                @config.each_with_index do |variables, index|
+                  @entries[index] = ::Gitlab::Config::Entry::Factory.new(Entry::Product::Variables)
+                    .value(variables)
+                    .with(parent: self, description: 'matrix variables definition.') # rubocop:disable CodeReuse/ActiveRecord
+                    .create!
+                end
+
+                @entries.each_value do |entry|
+                  entry.compose!(deps)
+                end
+              end
+            end
+
+            def value
+              strong_memoize(:value) do
+                @entries.values.map(&:value)
+              end
+            end
+
+            # rubocop:disable CodeReuse/ActiveRecord
+            def number_of_generated_jobs
+              value.sum do |config|
+                config.values.reduce(1) { |acc, values| acc * values.size }
+              end
+            end
+            # rubocop:enable CodeReuse/ActiveRecord
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/ci/config/entry/product/parallel.rb b/lib/gitlab/ci/config/entry/product/parallel.rb
new file mode 100644
index 00000000000..cd9eabbbc66
--- /dev/null
+++ b/lib/gitlab/ci/config/entry/product/parallel.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Ci
+    class Config
+      module Entry
+        ##
+        # Entry that represents a parallel job config.
+        #
+        module Product
+          class Parallel < ::Gitlab::Config::Entry::Simplifiable
+            strategy :ParallelBuilds, if: -> (config) { config.is_a?(Numeric) }
+            strategy :MatrixBuilds, if: -> (config) { config.is_a?(Hash) }
+
+            PARALLEL_LIMIT = 50
+
+            class ParallelBuilds < ::Gitlab::Config::Entry::Node
+              include ::Gitlab::Config::Entry::Validatable
+
+              validations do
+                validates :config, numericality: { only_integer: true,
+                                                   greater_than_or_equal_to: 2,
+                                                   less_than_or_equal_to: Entry::Product::Parallel::PARALLEL_LIMIT },
+                                   allow_nil: true
+              end
+
+              def value
+                { number: super.to_i }
+              end
+            end
+
+            class MatrixBuilds < ::Gitlab::Config::Entry::Node
+              include ::Gitlab::Config::Entry::Attributable
+              include ::Gitlab::Config::Entry::Configurable
+
+              PERMITTED_KEYS = %i[matrix].freeze
+
+              validations do
+                validates :config, allowed_keys: PERMITTED_KEYS
+                validates :config, required_keys: PERMITTED_KEYS
+              end
+
+              entry :matrix, Entry::Product::Matrix,
+                description: 'Variables definition for matrix builds'
+            end
+
+            class UnknownStrategy < ::Gitlab::Config::Entry::Node
+              def errors
+                ["#{location} should be an integer or a hash"]
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/ci/config/entry/product/variables.rb b/lib/gitlab/ci/config/entry/product/variables.rb
new file mode 100644
index 00000000000..ac4f70fb69e
--- /dev/null
+++ b/lib/gitlab/ci/config/entry/product/variables.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Ci
+    class Config
+      module Entry
+        ##
+        # Entry that represents variables for parallel matrix builds.
+        #
+        module Product
+          class Variables < ::Gitlab::Config::Entry::Node
+            include ::Gitlab::Config::Entry::Validatable
+
+            validations do
+              validates :config, variables: { array_values: true }
+              validates :config, length: {
+                minimum: 2,
+                too_short: 'requires at least %{count} items'
+              }
+            end
+
+            def self.default(**)
+              {}
+            end
+
+            def value
+              @config
+                .map { |key, value| [key.to_s, Array(value).map(&:to_s)] }
+                .to_h
+            end
+          end
+        end
+      end
+    end
+  end
+end