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.

2 files changed, 47 insertions, 0 deletions

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