Add sidekiq config propagate_traces to control trace header injection

Author: sl0thentr0py

CHANGELOG.md

@@ -4,6 +4,14 @@
 
 - Add new sidekiq config `report_only_dead_jobs` ([#2581](https://github.com/getsentry/sentry-ruby/pull/2581))
 - Add `max_nesting` of 10 to breadcrumbs data serialization ([#2583](https://github.com/getsentry/sentry-ruby/pull/2583))
+- Add sidekiq config `propagate_traces` to control trace header injection ([#2588](https://github.com/getsentry/sentry-ruby/pull/2588))
+
+  If you use schedulers you can get one large trace with all your jobs which is undesirable.
+  We recommend using the following to propagate traces only from the Rails server and not elsewhere.
+
+  ```ruby
+  config.sidekiq.propagate_traces = false unless Rails.const_defined?('Server')
+  ```
 
 ### Bug Fixes
 

sentry-sidekiq/lib/sentry/sidekiq/configuration.rb

@@ -24,9 +24,13 @@ class Configuration
       # Only report jobs that don't have `dead: false` set in the job's `sidekiq_options`
       attr_accessor :report_only_dead_jobs
 
+      # Whether we should inject headers while enqueuing the job in order to have a connected trace
+      attr_accessor :propagate_traces
+
       def initialize
         @report_after_job_retries = false
         @report_only_dead_jobs = false
+        @propagate_traces = true
       end
     end
   end

sentry-sidekiq/lib/sentry/sidekiq/sentry_context_middleware.rb

@@ -95,7 +95,10 @@ def call(worker_class, job, queue, _redis_pool)
 
         user = Sentry.get_current_scope.user
         job["sentry_user"] = user unless user.empty?
-        job["trace_propagation_headers"] ||= Sentry.get_trace_propagation_headers
+
+        if Sentry.configuration.sidekiq.propagate_traces
+          job["trace_propagation_headers"] ||= Sentry.get_trace_propagation_headers
+        end
 
         Sentry.with_child_span(op: "queue.publish", description: worker_class.to_s) do |span|
           set_span_data(span, id: job["jid"], queue: queue)

sentry-sidekiq/spec/sentry/sidekiq/configuration_spec.rb

@@ -26,4 +26,16 @@
       expect(subject.report_after_job_retries).to eq(false)
     end
   end
+
+  describe "#report_only_dead_jobs" do
+    it "has correct default value" do
+      expect(subject.report_only_dead_jobs).to eq(false)
+    end
+  end
+
+  describe "#propagate_traces" do
+    it "has correct default value" do
+      expect(subject.propagate_traces).to eq(true)
+    end
+  end
 end

sentry-sidekiq/spec/sentry/sidekiq/sentry_context_middleware_spec.rb

@@ -222,5 +222,19 @@
       expect(event.spans[0][:data]['messaging.message.id']).to eq(message_id)
       expect(event.spans[0][:data]['messaging.destination.name']).to eq('default')
     end
+
+    it "does not propagate headers with propagate_traces = false" do
+      perform_basic_setup do |config|
+        config.traces_sample_rate = 1.0
+        config.sidekiq.propagate_traces = false
+      end
+
+      Sentry.get_current_scope.set_span(transaction)
+
+      client.push('queue' => 'default', 'class' => HappyWorker, 'args' => [])
+
+      expect(queue.size).to be(1)
+      expect(queue.first["trace_propagation_headers"]).to be_nil
+    end
   end
 end