Merge branch 'zj-slash-commands-mattermost' into 'master'

Slash command for mattermost

Closes  #22540

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)


See merge request !7438

2 files changed, 28 insertions, 5 deletions

diff --git a/lib/api/helpers.rb b/lib/api/helpers.rb
index 84cc9200d1b..2c593dbb4ea 100644
--- a/lib/api/helpers.rb
+++ b/lib/api/helpers.rb
@@ -85,8 +85,8 @@ module API
       end
     end
 
-    def project_service
-      @project_service ||= user_project.find_or_initialize_service(params[:service_slug].underscore)
+    def project_service(project = user_project)
+      @project_service ||= project.find_or_initialize_service(params[:service_slug].underscore)
       @project_service || not_found!("Service")
     end
 
diff --git a/lib/api/services.rb b/lib/api/services.rb
index fc8598daa32..4d23499aa39 100644
--- a/lib/api/services.rb
+++ b/lib/api/services.rb
@@ -1,10 +1,10 @@
 module API
   # Projects API
   class Services < Grape::API
-    before { authenticate! }
-    before { authorize_admin_project }
-
     resource :projects do
+      before { authenticate! }
+      before { authorize_admin_project }
+
       # Set <service_slug> service for project
       #
       # Example Request:
@@ -59,5 +59,28 @@ module API
         present project_service, with: Entities::ProjectService, include_passwords: current_user.is_admin?
       end
     end
+
+    resource :projects do
+      desc 'Trigger a slash command' do
+        detail 'Added in GitLab 8.13'
+      end
+      post ':id/services/:service_slug/trigger' do
+        project = Project.find_with_namespace(params[:id]) || Project.find_by(id: params[:id])
+
+        # This is not accurate, but done to prevent leakage of the project names
+        not_found!('Service') unless project
+
+        service = project_service(project)
+
+        result = service.try(:active?) && service.try(:trigger, params)
+
+        if result
+          status result[:status] || 200
+          present result
+        else
+          not_found!('Service')
+        end
+      end
+    end
   end
 end