Migrate correlation and tracing code to LabKit

This change is a fairly straightforward refactor to extract the tracing
and correlation-id code from the gitlab rails codebase into the new
LabKit-Ruby project.

The corresponding import into LabKit-Ruby was in
https://gitlab.com/gitlab-org/labkit-ruby/merge_requests/1

The code itself remains very similar for now.

Extracting it allows us to reuse it in other projects, such as
Gitaly-Ruby. This will give us the advantages of correlation-ids and
distributed tracing in that project too.

1 files changed, 7 insertions, 9 deletions

diff --git a/config/initializers/tracing.rb b/config/initializers/tracing.rb
index ddd91150c90..3c8779f238f 100644
--- a/config/initializers/tracing.rb
+++ b/config/initializers/tracing.rb
@@ -1,16 +1,14 @@
 # frozen_string_literal: true
 
-if Gitlab::Tracing.enabled?
-  require 'opentracing'
-
+if Labkit::Tracing.enabled?
   Rails.application.configure do |config|
-    config.middleware.insert_after Gitlab::Middleware::CorrelationId, ::Gitlab::Tracing::RackMiddleware
+    config.middleware.insert_after Gitlab::Middleware::CorrelationId, ::Labkit::Tracing::RackMiddleware
   end
 
   # Instrument the Sidekiq client
   Sidekiq.configure_client do |config|
     config.client_middleware do |chain|
-      chain.add Gitlab::Tracing::Sidekiq::ClientMiddleware
+      chain.add Labkit::Tracing::Sidekiq::ClientMiddleware
     end
   end
 
@@ -18,20 +16,20 @@ if Gitlab::Tracing.enabled?
   if Sidekiq.server?
     Sidekiq.configure_server do |config|
       config.server_middleware do |chain|
-        chain.add Gitlab::Tracing::Sidekiq::ServerMiddleware
+        chain.add Labkit::Tracing::Sidekiq::ServerMiddleware
       end
     end
   end
 
   # Instrument Rails
-  Gitlab::Tracing::Rails::ActiveRecordSubscriber.instrument
-  Gitlab::Tracing::Rails::ActionViewSubscriber.instrument
+  Labkit::Tracing::Rails::ActiveRecordSubscriber.instrument
+  Labkit::Tracing::Rails::ActionViewSubscriber.instrument
 
   # In multi-processed clustered architectures (puma, unicorn) don't
   # start tracing until the worker processes are spawned. This works
   # around issues when the opentracing implementation spawns threads
   Gitlab::Cluster::LifecycleEvents.on_worker_start do
-    tracer = Gitlab::Tracing::Factory.create_tracer(Gitlab.process_name, Gitlab::Tracing.connection_string)
+    tracer = Labkit::Tracing::Factory.create_tracer(Gitlab.process_name, Labkit::Tracing.connection_string)
     OpenTracing.global_tracer = tracer if tracer
   end
 end