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// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
package main
import (
"context"
"io"
"log"
"net/http"
"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
"go.opentelemetry.io/otel"
"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/baggage"
"go.opentelemetry.io/otel/exporters/stdout/stdoutmetric"
"go.opentelemetry.io/otel/exporters/stdout/stdouttrace"
"go.opentelemetry.io/otel/propagation"
sdkmetric "go.opentelemetry.io/otel/sdk/metric"
"go.opentelemetry.io/otel/sdk/resource"
sdktrace "go.opentelemetry.io/otel/sdk/trace"
semconv "go.opentelemetry.io/otel/semconv/v1.20.0"
"go.opentelemetry.io/otel/trace"
)
func initTracer() (*sdktrace.TracerProvider, error) {
// Create stdout exporter to be able to retrieve
// the collected spans.
exporter, err := stdouttrace.New(stdouttrace.WithPrettyPrint())
if err != nil {
return nil, err
}
// For the demonstration, use sdktrace.AlwaysSample sampler to sample all traces.
// In a production application, use sdktrace.ProbabilitySampler with a desired probability.
tp := sdktrace.NewTracerProvider(
sdktrace.WithSampler(sdktrace.AlwaysSample()),
sdktrace.WithBatcher(exporter),
sdktrace.WithResource(resource.NewWithAttributes(semconv.SchemaURL, semconv.ServiceName("ExampleService"))),
)
otel.SetTracerProvider(tp)
otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
return tp, err
}
func initMeter() (*sdkmetric.MeterProvider, error) {
exp, err := stdoutmetric.New()
if err != nil {
return nil, err
}
mp := sdkmetric.NewMeterProvider(sdkmetric.WithReader(sdkmetric.NewPeriodicReader(exp)))
otel.SetMeterProvider(mp)
return mp, nil
}
func main() {
tp, err := initTracer()
if err != nil {
log.Fatal(err)
}
defer func() {
if err := tp.Shutdown(context.Background()); err != nil {
log.Printf("Error shutting down tracer provider: %v", err)
}
}()
mp, err := initMeter()
if err != nil {
log.Fatal(err)
}
defer func() {
if err := mp.Shutdown(context.Background()); err != nil {
log.Printf("Error shutting down meter provider: %v", err)
}
}()
uk := attribute.Key("username")
helloHandler := func(w http.ResponseWriter, req *http.Request) {
ctx := req.Context()
span := trace.SpanFromContext(ctx)
bag := baggage.FromContext(ctx)
span.AddEvent("handling this...", trace.WithAttributes(uk.String(bag.Member("username").Value())))
_, _ = io.WriteString(w, "Hello, world!\n")
}
otelHandler := otelhttp.NewHandler(http.HandlerFunc(helloHandler), "Hello")
http.Handle("/hello", otelHandler)
err = http.ListenAndServe(":7777", nil) //nolint:gosec // Ignoring G114: Use of net/http serve function that has no support for setting timeouts.
if err != nil {
log.Fatal(err)
}
}
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