add Zipkin shared_span_context Configuration

[ericmustin]

Summary

👋 Hello, would y'all take a PR to add support for configuring shared_span_context on the zipkin tracing configuration?

kuma/pkg/xds/envoy/listeners/v2/tracing_configurer.go

Lines 59 to 64 in d24b69d

	zipkinConfig := envoy_trace.ZipkinConfig{
	CollectorCluster: names.GetTracingClusterName(backendName),
	CollectorEndpoint: url.Path,
	TraceId_128Bit: cfg.TraceId128Bit,
	CollectorEndpointVersion: apiVersion(&cfg, url),
	}

This config option, which controls whether to reuse span_id for both client and server spans (a concept largely unique to zipkin), causes some users to experience issues downstream in Opentelemetry, so having the configurability would be super helpful. for context:

• Continue a span (client/server Span sharing; concept supported by Zipkin) open-telemetry/opentelemetry-specification#1007
• [exporter/datadog]: drop duplicate span ids from zipkin traces open-telemetry/opentelemetry-collector-contrib#2622

[jakubdyszkiewicz]

Hey @ericmustin

Sounds reasonable to add it, feel free to send a PR!

[ericmustin]

@jakubdyszkiewicz pushed up a pr, lmk what u think

[ericmustin]

just chiming in to say i tested the latest release (1.1.1) which contains the linked pr here and this does work as expected:

And now look, some nice, connected distributed traces of kong/kuma/envoy/nodejs in zipkin+opentelemetry, being displayed in datadog :)