Feature: Implement @jambonz/tracing library

[ajukes]

Move tracing to a new library and implement into Feature Server.

• For inbound calls extract X-Trace-ID | X-Span-ID from Sip Header
• Add X-Trace-ID | X-Span-ID to outgoing sip headers
• Simplify logging/debugging as all span creation is within same class
• This should allow us to have uncoupled servers/services under the same traceId in Jaeger.

Example Trace

[davehorton]

I'm not quite clear on how this works. You've added two new files but no changes to tracer.js and I can't see these files referenced anywhere

[davehorton]

also can you confirm this works with inbound calls as well as REST api triggered outdials?

[ajukes]

SipPropagator works similar to B3Propagator. here

Using the extract method to return a Context which then is used to create the span. I mean I could simply do the following in the call-tracer.js file

const ctx = trace.setSpanContext(context, {
      traceId,
      spanId,
      isRemote: true,
      traceFlags: TraceFlags.SAMPLED
    });

But it seemed cleaner to do the extracting of traceId, spanId in the SipPropagator class. I haven't hooked this into the tracer config but I suppose that could be the next natural step. Then instead of manually instantiating SipPropagator we could just leverage propagation.extract(context.active(), input); seen here

What are your thoughts? Unless I have completely missed the mark here.

I haven't tested REST calls yet, I will update the PR once tested.

[ajukes]

@davehorton Can you confirm that the traces for outbound REST calls were successfully being propagated before this PR? I have a feeling they wasn't as all outbound calls (regardless whether INBOUND or REST initiated the call) have a trace id of "0000000000000000" - I think there is an underlying bug here separate to this PR.

[ajukes]

I can see REST call in jaeger with a traceID representing the callSid so the propagator works as expected. However, what jambonz saves to the DB is "000000000000.."

[davehorton]

can you set this PR to draft status for now?

[ajukes]

@davehorton I just rebased but am unsure if I implemented correctly. let me know if I need to redo.

Thanks