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);
}
