Hi everyone,
I'm experimenting on how to add tracing to Kafka Streams.
One option is to override and access
`InternalTopologyBuilder#addProcessor`. Currently this method it is final,
and builder is not exposed as part of `StreamsBuilder`:
```
public class StreamsBuilder {
/** The actual topology that is constructed by this StreamsBuilder. */
private final Topology topology = new Topology();
/** The topology's internal builder. */
final InternalTopologyBuilder internalTopologyBuilder =
topology.internalTopologyBuilder;
private final InternalStreamsBuilder internalStreamsBuilder = new
InternalStreamsBuilder(internalTopologyBuilder);
```
The goal is that If `builder#addProcessor` is exposed, we could decorate
every `ProcessorSupplier` and capture traces from it:
```
@Override
public void addProcessor(String name, ProcessorSupplier supplier,
String... predecessorNames) {
super.addProcessor(name, new TracingProcessorSupplier(tracer, name,
supplier), predecessorNames);
}
```
Would it make sense to propose this as a change:
https://github.com/apache/kafka/compare/trunk...jeqo:tracing-topology ? or
maybe there is a better way to do this?
TopologyWrapper does something similar:
https://github.com/apache/kafka/blob/trunk/streams/src/test/java/org/apache/kafka/streams/TopologyWrapper.java
Thanks in advance for any help.
Cheers,
Jorge.
