Include failure_reason on BuildSerializer41111-show-failure-reason-in-job-page

- Add a method on Ci::Build presenter to map the failure to an
  appropriate description

Closes #41111

3 files changed, 26 insertions, 1 deletions

diff --git a/app/presenters/ci/build_presenter.rb b/app/presenters/ci/build_presenter.rb
index 255475e1fe6..655cb817a80 100644
--- a/app/presenters/ci/build_presenter.rb
+++ b/app/presenters/ci/build_presenter.rb
@@ -28,5 +28,22 @@ module Ci
           trigger_request.user_variables
         end
     end
+
+    def failure_reason_description
+      failure_descriptions[failure_reason]
+    end
+
+    private
+
+    def failure_descriptions
+      {
+        "unknown_failure" => "Unknown failure",
+        "script_failure" => "Script failure",
+        "api_failure" => "API failure",
+        "stuck_or_timeout_failure" => "Stuck or timeout failure",
+        "runner_system_failure" => "Runner system failure",
+        "missing_dependency_failure" => "Missing dependency failure"
+      }
+    end
   end
 end
diff --git a/app/serializers/job_entity.rb b/app/serializers/job_entity.rb
index 523b522d449..fea65b5d58f 100644
--- a/app/serializers/job_entity.rb
+++ b/app/serializers/job_entity.rb
@@ -25,7 +25,10 @@ class JobEntity < Grape::Entity
   expose :playable?, as: :playable
   expose :created_at
   expose :updated_at
-  expose :detailed_status, as: :status, with: StatusEntity
+  expose :status do
+    expose :failure_reason
+    expose :detailed_status, merge: true, with: StatusEntity
+  end
 
   private
 
@@ -50,4 +53,8 @@ class JobEntity < Grape::Entity
   def path_to(route, build)
     send("#{route}_path", build.project.namespace, build.project, build) # rubocop:disable GitlabSecurity/PublicSend
   end
+
+  def failure_reason
+    Ci::BuildPresenter.new(build).failure_reason_description
+  end
 end
diff --git a/spec/serializers/build_serializer_spec.rb b/spec/serializers/build_serializer_spec.rb
index 9673b11c2a2..147306dc790 100644
--- a/spec/serializers/build_serializer_spec.rb
+++ b/spec/serializers/build_serializer_spec.rb
@@ -39,6 +39,7 @@ describe BuildSerializer do
         expect(subject[:label]).to eq(status.label)
         expect(subject[:icon]).to eq(status.icon)
         expect(subject[:favicon]).to match_asset_path("/assets/ci_favicons/#{status.favicon}.ico")
+        expect(subject[:failure_reason]).to eq('Unknown failure')
       end
     end
   end