Logging & Structured Tracing with OpenTelemetry

OpenTelemetry (OTel)

This lesson explains the main concept clearly with beginner-friendly examples and background so you can learn why the code works.

OTel provides observability – traces, metrics, logs.

$ go get go.opentelemetry.io/otel/sdk@latest
$ go get go.opentelemetry.io/otel/exporters/trace/jaeger

import (
    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/trace"
    "go.opentelemetry.io/otel/sdk/trace"
    "go.opentelemetry.io/otel/exporters/trace/jaeger"
)

func initTracer() func(context.Context) error {
    exp, _ := jaeger.New(jaeger.WithCollectorEndpoint())
    tp := trace.NewTracerProvider(trace.WithBatcher(exp))
    otel.SetTracerProvider(tp)
    return tp.Shutdown
}

Wrap a handler:

func traced(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        ctx, span := otel.Tracer("myapp").Start(r.Context(), "request")
        defer span.End()
        next.ServeHTTP(w, r.WithContext(ctx))
    })
}