README
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telemetry
Common library for any Go code that wants to interface with telemetry.
telemetry expects everything to be configured via default otel environment variables to maximize portability and flexibility.
To modify the sample rate and sampling strategy, for example, you can use:
OTEL_TRACES_SAMPLER=parentbased_traceidratio
OTEL_TRACES_SAMPLER_ARG=0.001
See https://opentelemetry-python.readthedocs.io/en/latest/sdk/trace.sampling.html
Setup
telemetry is designed to minimize the boilerplate needed to get up and running quickly. To enable it, you simply add the following:
ctx := context.Background()
closeFunc := telemetry.EnableOTELTracing(ctx)
defer func() { _ = closeFunc(ctx) }()
From that point on, tracing is configured for you, and you can use it as normal. For example, you can run:
tracer := otel.Tracer("my-tracer")
Sampling
This library also contains convenience functions for forcing certain traces to be sampled. For example, to always sample HTTP requests with a specific HTTP header and value, you can run:
telemetry.AlwaysSampleHeaderHandler("name", "value", otelhttp.NewHandler(...)))
If the value is "*", then it will always sample requests that have the header set to any value.
telemetry includes this ability to force traces to be sampled more generally, though. If you want to force a trace to be sampled, you can call the following to add forced sampling to its context:
ctx := telemetry.AlwaysSample(r.Context())
That should be done for the root span.
Documentation
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Index ¶
- func AlwaysSample(ctx context.Context) context.Context
- func AlwaysSampleHeaderHandler(header string, value string, handler http.Handler) http.Handler
- func EnableOTELMetrics(ctx context.Context) func(context.Context) error
- func EnableOTELTracing(ctx context.Context) func(context.Context) error
- func ForceableSampler(wrapped sdktrace.Sampler) sdktrace.Sampler
- func NewHandler(handler http.Handler, filters ...ForceSampleFilter) http.Handler
- type ForceSampleFilter
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func AlwaysSample ¶
AlwaysSample returns a context that will always be sampled by the sampler.
func AlwaysSampleHeaderHandler ¶
AlwaysSampleHeaderHandler wraps the passed handler and always samples requests that have the specified header set to the specified value.
func EnableOTELMetrics ¶
EnableOTELMetrics enables OTEL metrics, configuring the OTEL provider using environment variables.
func EnableOTELTracing ¶
Sample rates should be configured via environment variables. See https://opentelemetry-python.readthedocs.io/en/latest/sdk/trace.sampling.html For example: OTEL_TRACES_SAMPLER=traceidratio OTEL_TRACES_SAMPLER_ARG=0.001
func ForceableSampler ¶
ForceableSampler returns a Sampler that uses the sampler from the environment but that checks the parent context for a special key that overrides the sampler to always sample.
func NewHandler ¶
func NewHandler(handler http.Handler, filters ...ForceSampleFilter) http.Handler
NewHandler wraps the passed handler and allows callers to set rules for things that should always be sampled.
Types ¶
type ForceSampleFilter ¶
func AlwaysSampleHTTPHeader ¶
func AlwaysSampleHTTPHeader(header string, value string) ForceSampleFilter
AlwaysSampleHTTPHeader returns a ForceSampleFilter that will always sample requests that have the specified header set to the specified value. If the value is "*", then it will always sample requests that have the header set to any value.
Source Files