Add event processor in OpenTelemetry SpanProcessor to link errors and transactions (#1983)

Author: sl0thentr0py

CHANGELOG.md

@@ -15,6 +15,8 @@
     end
     ```
 
+- Add global event processor in OpenTelemetry `SpanProcessor` to link errors with transactions [#1983](https://github.com/getsentry/sentry-ruby/pull/1983)
+
 
 ### Bug Fixes
 

sentry-opentelemetry/lib/sentry/opentelemetry/span_processor.rb

@@ -18,6 +18,7 @@ class SpanProcessor < ::OpenTelemetry::SDK::Trace::SpanProcessor
 
       def initialize
         @span_map = {}
+        setup_event_processor
       end
 
       def on_start(otel_span, parent_context)
@@ -152,6 +153,19 @@ def update_span_with_otel_data(sentry_span, otel_span)
         sentry_span.set_op(op)
         sentry_span.set_description(description)
       end
+
+      def setup_event_processor
+        Sentry.add_global_event_processor do |event, _hint|
+          span_context = ::OpenTelemetry::Trace.current_span.context
+          next event unless span_context.valid?
+
+          sentry_span = @span_map[span_context.hex_span_id]
+          next event unless sentry_span
+
+          event.contexts[:trace] ||= sentry_span.get_trace_context
+          event
+        end
+      end
     end
   end
 end

sentry-opentelemetry/spec/sentry/opentelemetry/span_processor_spec.rb

@@ -78,6 +78,23 @@
     it 'raises error on instantiation' do
       expect { described_class.new }.to raise_error(NoMethodError)
     end
+
+    context 'global event processor' do
+      let(:event_processor) { Sentry::Scope.global_event_processors.first }
+      let(:event) { Sentry::Event.new(configuration: Sentry.configuration) }
+      let(:hint) { {} }
+
+      before { subject.on_start(root_span, empty_context) }
+
+      it 'sets trace context on event' do
+        OpenTelemetry::Context.with_current(root_parent_context) do
+          event_processor.call(event, hint)
+          expect(event.contexts).to include(:trace)
+          expect(event.contexts[:trace][:trace_id]).to eq(root_span.context.hex_trace_id)
+          expect(event.contexts[:trace][:span_id]).to eq(root_span.context.hex_span_id)
+        end
+      end
+    end
   end
 
   describe '#on_start' do