Merge branch '17521-gitlab-ci-yml-templates' into 'master'

GitLab CI Yaml template dropdown

## What does this MR do?
Make it possible to select a dropdown for an easy start with GitLab CI.

## What are the relevant issue numbers?
Closes #17521

## TODO
- [ ] Backend
  - [x] CHANGELOG item
  - [x] Fix rubocop failure
  - [x] API Support
  - [x] New tests
  - [x] Add disclaimer to the top of the gitlab-ci.yml
- [ ] Frontend
  - [x] New tests

See merge request !4411

4 files changed, 39 insertions, 32 deletions

diff --git a/lib/api/api.rb b/lib/api/api.rb
index 0e7a1cc2623..f8f680a6311 100644
--- a/lib/api/api.rb
+++ b/lib/api/api.rb
@@ -33,7 +33,6 @@ module API
     mount ::API::Commits
     mount ::API::DeployKeys
     mount ::API::Files
-    mount ::API::Gitignores
     mount ::API::GroupMembers
     mount ::API::Groups
     mount ::API::Internal
@@ -58,6 +57,7 @@ module API
     mount ::API::Subscriptions
     mount ::API::SystemHooks
     mount ::API::Tags
+    mount ::API::Templates
     mount ::API::Triggers
     mount ::API::Users
     mount ::API::Variables
diff --git a/lib/api/entities.rb b/lib/api/entities.rb
index 3fde7aa989f..0ee96d4c67b 100644
--- a/lib/api/entities.rb
+++ b/lib/api/entities.rb
@@ -473,11 +473,11 @@ module API
       expose :content
     end
 
-    class GitignoresList < Grape::Entity
+    class TemplatesList < Grape::Entity
       expose :name
     end
 
-    class Gitignore < Grape::Entity
+    class Template < Grape::Entity
       expose :name, :content
     end
   end
diff --git a/lib/api/gitignores.rb b/lib/api/gitignores.rb
deleted file mode 100644
index 270c9501dd2..00000000000
--- a/lib/api/gitignores.rb
+++ /dev/null
@@ -1,29 +0,0 @@
-module API
-  class Gitignores < Grape::API
-
-    # Get the list of the available gitignore templates
-    #
-    # Example Request:
-    #   GET /gitignores
-    get 'gitignores' do
-      present Gitlab::Gitignore.all, with: Entities::GitignoresList
-    end
-
-    # Get the text for a specific gitignore
-    #
-    # Parameters:
-    #   name (required) - The name of a license
-    #
-    # Example Request:
-    #   GET /gitignores/Elixir
-    #
-    get 'gitignores/:name' do
-      required_attributes! [:name]
-
-      gitignore = Gitlab::Gitignore.find(params[:name])
-      not_found!('.gitignore') unless gitignore
-
-      present gitignore, with: Entities::Gitignore
-    end
-  end
-end
diff --git a/lib/api/templates.rb b/lib/api/templates.rb
new file mode 100644
index 00000000000..18408797756
--- /dev/null
+++ b/lib/api/templates.rb
@@ -0,0 +1,36 @@
+module API
+  class Templates < Grape::API
+    TEMPLATE_TYPES = {
+      gitignores:     Gitlab::Template::Gitignore,
+      gitlab_ci_ymls: Gitlab::Template::GitlabCiYml
+    }.freeze
+
+    TEMPLATE_TYPES.each do |template, klass|
+      # Get the list of the available template
+      #
+      # Example Request:
+      #   GET /gitignores
+      #   GET /gitlab_ci_ymls
+      get template.to_s do
+        present klass.all, with: Entities::TemplatesList
+      end
+
+      # Get the text for a specific template
+      #
+      # Parameters:
+      #   name (required) - The name of a template
+      #
+      # Example Request:
+      #   GET /gitignores/Elixir
+      #   GET /gitlab_ci_ymls/Ruby
+      get "#{template}/:name" do
+        required_attributes! [:name]
+
+        new_template = klass.find(params[:name])
+        not_found!(template.to_s.singularize) unless new_template
+
+        present new_template, with: Entities::Template
+      end
+    end
+  end
+end