Allow projects to be started from a template

Started implementation for the first iteration of
gitlab-org/gitlab-ce#32420. This will allow users to select a template
to start with, instead of an empty repository in the project just
created.

Internally this is basically a small extension of the ImportExport
GitLab projects we already support. We just import a certain import
tar archive. This commits includes the first one: Ruby on Rails. In the
future more will be added.

8 files changed, 101 insertions, 36 deletions

diff --git a/app/assets/images/project_templates/rails.png b/app/assets/images/project_templates/rails.png
new file mode 100644
index 00000000000..dbee6bf6227
--- /dev/null
+++ b/app/assets/images/project_templates/rails.png
diff --git a/app/controllers/import/gitlab_projects_controller.rb b/app/controllers/import/gitlab_projects_controller.rb
index 36d246d185b..6463d2dfd5b 100644
--- a/app/controllers/import/gitlab_projects_controller.rb
+++ b/app/controllers/import/gitlab_projects_controller.rb
@@ -12,15 +12,7 @@ class Import::GitlabProjectsController < Import::BaseController
       return redirect_back_or_default(options: { alert: "You need to upload a GitLab project export archive." })
     end
 
-    import_upload_path = Gitlab::ImportExport.import_upload_path(filename: project_params[:file].original_filename)
-
-    FileUtils.mkdir_p(File.dirname(import_upload_path))
-    FileUtils.copy_entry(project_params[:file].path, import_upload_path)
-
-    @project = Gitlab::ImportExport::ProjectCreator.new(project_params[:namespace_id],
-                                                        current_user,
-                                                        import_upload_path,
-                                                        project_params[:path]).execute
+    @project = ::Projects::GitlabProjectsImporterService.new(current_user, project_params).execute
 
     if @project.saved?
       redirect_to(
diff --git a/app/controllers/projects_controller.rb b/app/controllers/projects_controller.rb
index c769693255c..275474d02f6 100644
--- a/app/controllers/projects_controller.rb
+++ b/app/controllers/projects_controller.rb
@@ -27,7 +27,12 @@ class ProjectsController < Projects::ApplicationController
   end
 
   def create
-    @project = ::Projects::CreateService.new(current_user, project_params).execute
+    @project =
+      if project_from_template?
+        ::Projects::CreateFromTemplateService.new(current_user, project_params).execute
+      else
+        ::Projects::CreateService.new(current_user, project_params).execute
+      end
 
     if @project.saved?
       cookies[:issue_board_welcome_hidden] = { path: project_path(@project), value: nil, expires: Time.at(0) }
@@ -324,6 +329,7 @@ class ProjectsController < Projects::ApplicationController
       :runners_token,
       :tag_list,
       :visibility_level,
+      :template_title,
 
       project_feature_attributes: %i[
         builds_access_level
@@ -345,6 +351,10 @@ class ProjectsController < Projects::ApplicationController
     false
   end
 
+  def project_from_template?
+    project_params[:template_title]&.present?
+  end
+
   def project_view_files?
     if current_user
       current_user.project_view == 'files'
diff --git a/app/models/project.rb b/app/models/project.rb
index d827bfaa806..e7c404bf817 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -71,6 +71,7 @@ class Project < ActiveRecord::Base
 
   attr_accessor :new_default_branch
   attr_accessor :old_path_with_namespace
+  attr_accessor :template_title
   attr_writer :pipeline_status
 
   alias_attribute :title, :name
diff --git a/app/services/projects/create_from_template_service.rb b/app/services/projects/create_from_template_service.rb
new file mode 100644
index 00000000000..3fc5c4ad157
--- /dev/null
+++ b/app/services/projects/create_from_template_service.rb
@@ -0,0 +1,14 @@
+module Projects
+  class CreateFromTemplateService < BaseService
+    def initialize(user, params)
+      @current_user, @params = user, params.dup
+    end
+
+    def execute
+      params[:file] = Gitlab::ProjectTemplate.find(params[:template_title]).file
+
+      @params[:from_template] = true
+      GitlabProjectsImporterService.new(@current_user, @params).execute
+    end
+  end
+end
diff --git a/app/services/projects/gitlab_projects_importer_service.rb b/app/services/projects/gitlab_projects_importer_service.rb
new file mode 100644
index 00000000000..4cb98c54de5
--- /dev/null
+++ b/app/services/projects/gitlab_projects_importer_service.rb
@@ -0,0 +1,33 @@
+# This service is an adapter used to for the GitLab Import feature, and
+# creating a project from a template.
+# The latter will under the hood just import an archive supplied by GitLab.
+module Projects
+  class GitlabProjectsImporterService
+    attr_reader :current_user, :params
+
+    def initialize(user, params)
+      @current_user, @params = user, params.dup
+    end
+
+    def execute
+      FileUtils.mkdir_p(File.dirname(import_upload_path))
+      FileUtils.copy_entry(file.path, import_upload_path)
+
+      Gitlab::ImportExport::ProjectCreator.new(params[:namespace_id],
+                                               current_user,
+                                               import_upload_path,
+                                               params[:path]).execute
+    end
+
+    private
+
+    def import_upload_path
+      @import_upload_path ||= Gitlab::ImportExport
+        .import_upload_path(filename: "#{params[:namespace_id]}-#{params[:path]}")
+    end
+
+    def file
+      params[:file]
+    end
+  end
+end
diff --git a/app/views/projects/_project_templates.html.haml b/app/views/projects/_project_templates.html.haml
new file mode 100644
index 00000000000..bef64ca7433
--- /dev/null
+++ b/app/views/projects/_project_templates.html.haml
@@ -0,0 +1,8 @@
+.col-sm-12.template-buttons
+  - Gitlab::ProjectTemplate.all.each do |template|
+    -# The title should be the value posted to the controller, a pretty name to print would be
+    -# template.name
+    = template.title
+    = image_tag(template.logo_path)
+
+  = f.text_field :template_title, placeholder: "rails", class: "form-control", tabindex: 2, autofocus: true, required: true
diff --git a/app/views/projects/new.html.haml b/app/views/projects/new.html.haml
index a2d7a21d5f6..c01645e2ec9 100644
--- a/app/views/projects/new.html.haml
+++ b/app/views/projects/new.html.haml
@@ -17,36 +17,17 @@
           Create or Import your project from popular Git services
     .col-lg-9
       = form_for @project, html: { class: 'new_project' } do |f|
-        .row
-          .form-group.col-xs-12.col-sm-6
-            = f.label :namespace_id, class: 'label-light' do
-              %span
-                Project path
-            .form-group
-              .input-group
-                - if current_user.can_select_namespace?
-                  .input-group-addon
-                    = root_url
-                  = f.select :namespace_id, namespaces_options(namespace_id_from(params) || :current_user, display_path: true, extra_group: namespace_id_from(params)), {}, { class: 'select2 js-select-namespace', tabindex: 1}
-
-                - else
-                  .input-group-addon.static-namespace
-                    #{root_url}#{current_user.username}/
-                  = f.hidden_field :namespace_id, value: current_user.namespace_id
-          .form-group.col-xs-12.col-sm-6.project-path
-            = f.label :path, class: 'label-light' do
-              %span
-                Project name
-            = f.text_field :path, placeholder: "my-awesome-project", class: "form-control", tabindex: 2, autofocus: true, required: true
-        - if current_user.can_create_group?
-          .help-block
-            Want to house several dependent projects under the same namespace?
-            = link_to "Create a group", new_group_path
+        .project-template.js-toggle-container
+          .form_group.clearfix
+            = f.label :template_project, class: 'label-light' do
+              Start from template
+            .col-sm-12.import-buttons
+              = render 'project_templates', f: f
 
         - if import_sources_enabled?
           .project-import.js-toggle-container
             .form-group.clearfix
-              = f.label :visibility_level, class: 'label-light' do
+              = f.label :visibility_level, class: 'label-light' do #the label here seems wrong
                 Import project from
               .col-sm-12.import-buttons
                 %div
@@ -90,6 +71,32 @@
             .js-toggle-content.hide
               = render "shared/import_form", f: f
 
+        .row
+          .form-group.col-xs-12.col-sm-6
+            = f.label :namespace_id, class: 'label-light' do
+              %span
+                Project path
+            .form-group
+              .input-group
+                - if current_user.can_select_namespace?
+                  .input-group-addon
+                    = root_url
+                  = f.select :namespace_id, namespaces_options(namespace_id_from(params) || :current_user, display_path: true, extra_group: namespace_id_from(params)), {}, { class: 'select2 js-select-namespace', tabindex: 1}
+
+                - else
+                  .input-group-addon.static-namespace
+                    #{root_url}#{current_user.username}/
+                  = f.hidden_field :namespace_id, value: current_user.namespace_id
+          .form-group.col-xs-12.col-sm-6.project-path
+            = f.label :path, class: 'label-light' do
+              %span
+                Project name
+            = f.text_field :path, placeholder: "my-awesome-project", class: "form-control", tabindex: 2, autofocus: true, required: true
+        - if current_user.can_create_group?
+          .help-block
+            Want to house several dependent projects under the same namespace?
+            = link_to "Create a group", new_group_path
+
         .form-group
           = f.label :description, class: 'label-light' do
             Project description