public static ISpanBuilder ObtainConsumerSpanBuilder(ITracer tracer, Headers headers, string spanName)
{
// See if we have a trace header
IHeader traceHeader = null;
// For whatever insane reason this linq query is not working ??
//traceHeader = cr.Message.Headers.FirstOrDefault(p => p.Key == "tracing-id");
foreach (var header in headers)
{
bool isKey = header.Key == "tracing-id";
if (isKey)
{
traceHeader = header;
break;
}
}
ISpanBuilder spanBuilder;
if (traceHeader != null)
{
var map = KafkaTracingContextHelper.Decode(traceHeader.GetValueBytes());
var ctx = tracer.Extract(BuiltinFormats.TextMap, new TextMapExtractAdapter(map));
spanBuilder = tracer.BuildSpan(spanName)
.WithTag(Tags.SpanKind.Key, Tags.SpanKindConsumer)
.AsChildOf(ctx);
}
else
{
spanBuilder = tracer.BuildSpan(spanName)
.WithTag(Tags.SpanKind.Key, Tags.SpanKindConsumer);
}
return(spanBuilder);
}
public Task ConsumeAsync(CancellationToken stoppingToken)
{
return(Task.Run(async() =>
{
var topics = string.Join(",", _consumer.Subscription);
while (!stoppingToken.IsCancellationRequested)
{
try
{
ConsumeResult <TKey, string> cr = _consumer.Consume(stoppingToken);
if (cr.IsPartitionEOF)
{
continue;
}
IHeader messageTypeHeader = cr.Message.Headers.First(h => h.Key == "type");
string eventType = Encoding.UTF8.GetString(messageTypeHeader.GetValueBytes());
IDomainEvent <TKey> @event = _eventDeserializer.Deserialize <TKey>(eventType, cr.Message.Value);
if (@event == null)
{
throw new SerializationException($"unable to deserialize event {eventType} : {cr.Message.Value}");
}
await OnEventReceived(@event);
}
catch (OperationCanceledException ex)
{
OnConsumerStopped(ex);
throw;
}
catch (Exception ex)
{
OnExceptionThrown(ex);
}
}
}, stoppingToken));
}
