private void ProcessStartEvent(TRequest request, Uri requestUrl) { Logger.Trace()?.Log("Processing start event... Request URL: {RequestUrl}", Http.Sanitize(requestUrl)); var transaction = _agent.Tracer.CurrentTransaction; if (transaction == null) { Logger.Debug()?.Log("No current transaction, skip creating span for outgoing HTTP request"); return; } var span = ExecutionSegmentCommon.StartSpanOnCurrentExecutionSegment(_agent, $"{RequestGetMethod(request)} {requestUrl.Host}", ApiConstants.TypeExternal, ApiConstants.SubtypeHttp, InstrumentationFlag.HttpClient, true); if (!ProcessingRequests.TryAdd(request, span)) { // Consider improving error reporting - see https://github.com/elastic/apm-agent-dotnet/issues/280 Logger.Error()?.Log("Failed to add to ProcessingRequests - ???"); return; } if (!RequestHeadersContain(request, TraceContext.TraceParentHeaderName)) { // We call TraceParent.BuildTraceparent explicitly instead of DistributedTracingData.SerializeToString because // in the future we might change DistributedTracingData.SerializeToString to use some other internal format // but here we want the string to be in W3C 'traceparent' header format. RequestHeadersAdd(request, TraceContext.TraceParentHeaderName, TraceContext.BuildTraceparent(span.OutgoingDistributedTracingData)); } if (transaction is Transaction t) { if (t.ConfigSnapshot.UseElasticTraceparentHeader) { if (!RequestHeadersContain(request, TraceContext.TraceParentHeaderNamePrefixed)) { RequestHeadersAdd(request, TraceContext.TraceParentHeaderNamePrefixed, TraceContext.BuildTraceparent(span.OutgoingDistributedTracingData)); } } } if (!RequestHeadersContain(request, TraceContext.TraceStateHeaderName) && transaction.OutgoingDistributedTracingData.HasTraceState) { RequestHeadersAdd(request, TraceContext.TraceStateHeaderName, TraceContext.BuildTraceState(transaction.OutgoingDistributedTracingData)); } if (!span.ShouldBeSentToApmServer) { return; } span.Context.Http = new Http { Method = RequestGetMethod(request) }; span.Context.Http.SetUrl(requestUrl); }