Merge branch '534-jenkins-ci-service-doesn-t-send-x-gitlab-event-header' into 'master'

Add standard web hook headers to Jenkins CI post

Closes #534

The Jenkins web hook was not sending the standard web hook headers.
Specifically, the `gitlab-plugin` for Jenkins needs to use the
`X-GitLab-Event` header. This makes our EE service unable to work with
the newer GitLab Plugin for Jenkins.

See https://github.com/jenkinsci/gitlab-plugin/issues/272

See merge request !374

app/models/hooks/service_hook.rb

 class ServiceHook < WebHook
   belongs_to :service
 
-  def execute(data)
-    super(data, 'service_hook')
+  def execute(data, hook_name = 'service_hook')
+    super(data, hook_name)
   end
 end

app/models/project_services/jenkins_service.rb

@@ -46,14 +46,9 @@ class JenkinsService < CiService
   end
 
   def execute(data)
-    self.class.post(
-      hook_url,
-      body: data.to_json,
-      headers: {
-        'Content-Type' => 'application/json',
-        'Authorization' => "Basic #{auth}"
-      }
-    )
+    return unless supported_events.include?(data[:object_kind])
+
+    service_hook.execute(data, "#{data[:object_kind]}_hook")
   end
 
   def test(data)

spec/models/project_services/jenkins_service_spec.rb

@@ -74,6 +74,30 @@ describe JenkinsService do
     end
   end
 
+  describe '#execute' do
+    it 'adds default web hook headers to the request' do
+      user = create(:user, username: 'username')
+      project = create(:project, name: 'project')
+      push_sample_data = Gitlab::PushDataBuilder.build_sample(project, user)
+      jenkins_service = described_class.create(
+        active: true,
+        project: project,
+        properties: {
+          jenkins_url: 'http://jenkins.example.com/',
+          project_name: 'my_project'
+        }
+      )
+      stub_request(:post, jenkins_service.hook_url)
+
+      jenkins_service.execute(push_sample_data)
+
+      expect(
+        a_request(:post, jenkins_service.hook_url)
+          .with(headers: { 'X-Gitlab-Event' => 'Push Hook' })
+      ).to have_been_made.once
+    end
+  end
+
   describe 'Stored password invalidation' do
     let(:project) { create(:project) }