1
0
mirror of https://github.com/open-telemetry/opentelemetry-go.git synced 2024-12-12 10:04:29 +02:00
opentelemetry-go/example/passthrough
Anthony Mirabella 7728a52135
Remove dependency on metrics packages (#1988)
* Declare internal/metric module to version it separately

Signed-off-by: Anthony J Mirabella <a9@aneurysm9.com>

* Remove dependency on metrics module from soon-to-be-stable modules

Signed-off-by: Anthony J Mirabella <a9@aneurysm9.com>

* Add PR ID to CHANGELOG

Signed-off-by: Anthony J Mirabella <a9@aneurysm9.com>

* rename metric/oteltest to metric/metrictest

Signed-off-by: Anthony J Mirabella <a9@aneurysm9.com>

* Fix metrictest package name in CHANGELOG

Signed-off-by: Anthony J Mirabella <a9@aneurysm9.com>
2021-06-10 15:05:25 -04:00
..
handler Add Passthrough example (#1912) 2021-05-18 14:03:10 -07:00
go.mod Remove dependency on metrics packages (#1988) 2021-06-10 15:05:25 -04:00
go.sum Bump github.com/google/go-cmp from 0.5.5 to 0.5.6 (#1954) 2021-06-01 11:53:02 -07:00
main.go Refactor exporter creation functions (#1985) 2021-06-10 09:22:47 -07:00
README.md Refactor exporter creation functions (#1985) 2021-06-10 09:22:47 -07:00

"Passthrough" setup for OpenTelemetry

Some Go programs may wish to propagate context without recording spans. To do this in OpenTelemetry, simply install TextMapPropagators, but do not install a TracerProvider using the SDK. This works because the default TracerProvider implementation returns a "Non-Recording" span that keeps the context of the caller but does not record spans.

For example, when you initialize your global settings, the following will propagate context without recording spans:

// Setup Propagators only
otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))

But the following will propagate context and create new, potentially recorded spans:

// Setup SDK
exp, _ := stdout.New(stdout.WithPrettyPrint())
tp = sdktrace.NewTracerProvider(
    sdktrace.WithBatcher(exp),
)
otel.SetTracerProvider(tp)
// Setup Propagators
otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))

The Demo

The demo has the following call structure:

Outer -> Passthrough -> Inner

If all components had both an SDK and propagators registered, we would expect the trace to look like:

|-------outer---------|
 |-Passthrough recv-|
  |Passthrough send|
    |---inner---|

However, in this demo, only the outer and inner have TracerProvider backed by the SDK. All components have Propagators set. In this case, we expect to see:

|-------outer---------|
    |---inner---|