Provide a performance bar link to the Jaeger UI

Jaeger is a distributed tracing tool. This change adds a "Tracing" link
to the performance bar to directly link to a current request in Jaeger.

This is useful for two reasons: 1 - it provides affordance to developers
that the distributed tracing tool is available, so that it can quickly
be discovered. 2 - it allows developers to quickly find a specific trace
without having to manually navigate to a second user-interface.

2 files changed, 32 insertions, 0 deletions

diff --git a/lib/gitlab/tracing.rb b/lib/gitlab/tracing.rb
index 3c4db42ac06..0d9b0be1c8e 100644
--- a/lib/gitlab/tracing.rb
+++ b/lib/gitlab/tracing.rb
@@ -13,5 +13,24 @@ module Gitlab
     def self.connection_string
       ENV['GITLAB_TRACING']
     end
+
+    def self.tracing_url_template
+      ENV['GITLAB_TRACING_URL']
+    end
+
+    def self.tracing_url_enabled?
+      enabled? && tracing_url_template.present?
+    end
+
+    # This will provide a link into the distributed tracing for the current trace,
+    # if it has been captured.
+    def self.tracing_url
+      return unless tracing_url_enabled?
+
+      tracing_url_template % {
+        correlation_id: Gitlab::CorrelationId.current_id.to_s,
+        service: Gitlab.process_name
+      }
+    end
   end
 end
diff --git a/lib/peek/views/tracing.rb b/lib/peek/views/tracing.rb
new file mode 100644
index 00000000000..0de32a8fdda
--- /dev/null
+++ b/lib/peek/views/tracing.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module Peek
+  module Views
+    class Tracing < View
+      def results
+        {
+          tracing_url: Gitlab::Tracing.tracing_url
+        }
+      end
+    end
+  end
+end