Documentation
¶
Overview ¶
Package datadogtrace provides a LogLayer plugin that injects Datadog APM trace and span IDs into log entries, enabling Datadog's log/trace correlation feature.
The plugin reads the active span via a user-supplied Extract function from the per-call context.Context (attached via WithContext). It then emits dd.trace_id, dd.span_id, plus the optional dd.service / dd.env / dd.version reserved attributes.
The plugin does not depend on any specific Datadog tracer library: the user wires up the extractor for whichever version of dd-trace-go (v1, v2, or an OTel-bridged tracer) they already use. This keeps LogLayer's dependency footprint minimal for users who don't need Datadog APM correlation.
Usage with dd-trace-go v1:
import (
"context"
ddtracer "gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
"go.loglayer.dev"
"go.loglayer.dev/plugins/datadogtrace"
"go.loglayer.dev/transports/structured"
)
ddtracer.Start(ddtracer.WithService("checkout-api"))
defer ddtracer.Stop()
log := loglayer.New(loglayer.Config{
Transport: structured.New(structured.Config{}),
Plugins: []loglayer.Plugin{
datadogtrace.New(datadogtrace.Config{
Service: "checkout-api",
Env: "production",
Extract: func(ctx context.Context) (uint64, uint64, bool) {
if span, ok := ddtracer.SpanFromContext(ctx); ok {
sc := span.Context()
return sc.TraceID(), sc.SpanID(), true
}
return 0, 0, false
},
}),
},
})
// Inside an HTTP handler whose context carries a span, bind once:
handlerLog := log.WithContext(r.Context())
handlerLog.Info("served")
// Output includes dd.trace_id and dd.span_id, ready for log/trace
// correlation in the Datadog UI.
See https://go.loglayer.dev for usage guides and the full API reference.
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func New ¶
func New(cfg Config) loglayer.Plugin
New constructs the plugin. Panics if cfg.Extract is nil. The returned plugin implements [loglayer.DataHook]; when cfg.OnError is set it's wrapped via [loglayer.WithErrorReporter] so recovered hook panics reach the caller-supplied callback instead of the framework's stderr default.
Example ¶
New returns a plugin that injects dd.trace_id and dd.span_id onto every entry. Extract is required; wire it to whichever Datadog tracer your service uses (dd-trace-go v1, v2, or an OTel bridge).
t := lltesting.New(lltesting.Config{})
log := loglayer.New(loglayer.Config{
Transport: t,
DisableFatalExit: true,
Plugins: []loglayer.Plugin{
datadogtrace.New(datadogtrace.Config{
Service: "checkout-api",
Env: "production",
Extract: func(ctx context.Context) (uint64, uint64, bool) {
// Replace with ddtracer.SpanFromContext(ctx) etc.
return 0, 0, false
},
}),
},
})
log.Info("served")
Types ¶
type Config ¶
type Config struct {
// ID for the plugin. Defaults to "datadog-trace-injector".
ID string
// Extract returns the active span's trace and span IDs from the
// per-call context. Returns ok=false when no span is attached or
// when the IDs aren't yet available.
//
// Required. Wire it to whatever tracer library your service uses.
// See the package doc for the standard dd-trace-go v1 wiring.
Extract func(ctx context.Context) (traceID, spanID uint64, ok bool)
// Service, Env, Version are optional Datadog reserved attributes
// emitted on every entry as dd.service / dd.env / dd.version.
// Set them once here to avoid duplicating them in every log call.
// Empty values are omitted from the output.
Service string
Env string
Version string
// OnError is forwarded to the resulting Plugin's OnError. The
// LogLayer framework recovers extractor panics centrally; if you
// pass a non-nil OnError here, you'll see the recovered panic.
// Defaults to silent.
OnError func(err error)
}
Config holds plugin configuration.
Source Files