opentelemetrytracer: log the number of exported spans

Author: joaopgrassi

source/extensions/tracers/opentelemetry/grpc_trace_exporter.cc

@@ -42,6 +42,7 @@ void OpenTelemetryGrpcTraceExporter::onFailure(Grpc::Status::GrpcStatus status,
 bool OpenTelemetryGrpcTraceExporter::log(const ExportTraceServiceRequest& request) {
   client_->send(service_method_, request, *this, Tracing::NullSpan::instance(),
                 Http::AsyncClient::RequestOptions());
+  OpenTelemetryTraceExporter::logExportedSpans(request);
   return true;
 }
 

source/extensions/tracers/opentelemetry/http_trace_exporter.cc

@@ -70,6 +70,8 @@ bool OpenTelemetryHttpTraceExporter::log(const ExportTraceServiceRequest& reques
   Http::AsyncClient::Request* in_flight_request =
       thread_local_cluster->httpAsyncClient().send(std::move(message), *this, options);
 
+  OpenTelemetryTraceExporter::logExportedSpans(request);
+
   if (in_flight_request == nullptr) {
     return false;
   }

source/extensions/tracers/opentelemetry/trace_exporter.h

@@ -29,6 +29,24 @@ class OpenTelemetryTraceExporter : public Logger::Loggable<Logger::Id::tracing>
    * @return false When sending the request failed.
    */
   virtual bool log(const ExportTraceServiceRequest& request) = 0;
+
+  /**
+   * @brief Logs as debug the number of exported spans.
+   *
+   * @param request The protobuf-encoded OTLP trace request.
+   */
+  void logExportedSpans(const ExportTraceServiceRequest& request) {
+    if (!ENVOY_LOG_COMP_LEVEL_FINE_GRAIN_IF(ENVOY_LOGGER(), debug)) {
+      return;
+    }
+
+    if (request.resource_spans(0).has_resource()) {
+      if (request.resource_spans(0).scope_spans(0).has_scope()) {
+        ENVOY_LOG(debug, "Number of exported spans: {}",
+                  request.resource_spans(0).scope_spans(0).spans_size());
+      }
+    }
+  }
 };
 
 using OpenTelemetryTraceExporterPtr = std::unique_ptr<OpenTelemetryTraceExporter>;