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mirror of https://github.com/open-telemetry/opentelemetry-go.git synced 2024-12-04 09:43:23 +02:00
opentelemetry-go/example/passthrough
Tyler Yahn 12e16d41e7
Bump golang.org/x/sys/unix (#3235)
* Bump golang.org/x/sys/unix

Fix #3234

Address GO-2022-0493 by upgrading golang.org/x/sys/unix from
v0.0.0-20210423185535-09eb48e85fd7 to
v0.0.0-20220919091848-fb04ddd9f9c8.

* Add changes to changelog
2022-09-27 09:08:34 -07:00
..
handler Use already enabled revive linter and add depguard (#2883) 2022-05-19 15:15:07 -05:00
go.mod Bump golang.org/x/sys/unix (#3235) 2022-09-27 09:08:34 -07:00
go.sum Bump golang.org/x/sys/unix (#3235) 2022-09-27 09:08:34 -07:00
main.go Use already enabled revive linter and add depguard (#2883) 2022-05-19 15:15:07 -05:00
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---|