Handle Rack hijacking interface

instrumentation/rack/lib/opentelemetry/instrumentation/rack/middlewares/event_handler.rb

@@ -109,7 +109,7 @@ def on_finish(request, response)
             span = OpenTelemetry::Instrumentation::Rack.current_span
             return unless span.recording?
 
-            add_response_attributes(span, response) if response
+            add_response_attributes(span, response) if response && !request.env.key?('rack.hijack?')
           rescue StandardError => e
             OpenTelemetry.handle_error(exception: e)
           ensure

instrumentation/rack/lib/opentelemetry/instrumentation/rack/middlewares/tracer_middleware.rb

@@ -81,7 +81,7 @@ def call(env)
                 request_span.add_event('http.proxy.request.started', timestamp: request_start_time) unless request_start_time.nil?
                 OpenTelemetry::Instrumentation::Rack.with_span(request_span) do
                   @app.call(env).tap do |status, headers, response|
-                    set_attributes_after_request(request_span, status, headers, response)
+                    set_attributes_after_request(request_span, status, headers, response) unless env.key?('rack.hijack?')
                     config[:response_propagators].each { |propagator| propagator.inject(headers) }
                   end
                 end

instrumentation/rack/test/opentelemetry/instrumentation/rack/middlewares/event_handler_test.rb

@@ -105,6 +105,19 @@
       _(proxy_event).must_be_nil
     end
 
+    describe 'with an hijacked response' do
+      let(:service) do
+        lambda do |env|
+          env['rack.hijack?'] = true
+          [-1, {}, []]
+        end
+      end
+
+      it 'track a span without error' do
+        _(rack_span.status.code).must_equal OpenTelemetry::Trace::Status::UNSET
+      end
+    end
+
     describe 'when baggage is set' do
       let(:headers) do
         Hash(

instrumentation/rack/test/opentelemetry/instrumentation/rack/middlewares/tracer_middleware_test.rb

@@ -72,6 +72,19 @@
       _(first_span.status.code).must_equal OpenTelemetry::Trace::Status::UNSET
     end
 
+    describe 'with an hijacked response' do
+      let(:app) do
+        lambda do |env|
+          env['rack.hijack?'] = true
+          [-1, {}, []]
+        end
+      end
+
+      it 'track a span without error' do
+        _(first_span.status.code).must_equal OpenTelemetry::Trace::Status::UNSET
+      end
+    end
+
     it 'has no parent' do
       _(first_span.parent_span_id).must_equal OpenTelemetry::Trace::INVALID_SPAN_ID
     end