Add logs to dice example

Use slog to log a message on the server handler.

example/dice/go.mod

@@ -1,14 +1,18 @@
 module go.opentelemetry.io/otel/example/dice
 
-go 1.21
+go 1.22
 
 require (
+	go.opentelemetry.io/contrib/bridges/otelslog v0.1.0
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.51.0
 	go.opentelemetry.io/otel v1.26.0
+	go.opentelemetry.io/otel/exporters/stdout/stdoutlog v0.2.0-alpha
 	go.opentelemetry.io/otel/exporters/stdout/stdoutmetric v1.26.0
 	go.opentelemetry.io/otel/exporters/stdout/stdouttrace v1.26.0
+	go.opentelemetry.io/otel/log v0.2.0-alpha
 	go.opentelemetry.io/otel/metric v1.26.0
 	go.opentelemetry.io/otel/sdk v1.26.0
+	go.opentelemetry.io/otel/sdk/log v0.2.0-alpha
 	go.opentelemetry.io/otel/sdk/metric v1.26.0
 )
 
@@ -33,3 +37,9 @@ replace go.opentelemetry.io/otel/metric => ../../metric
 replace go.opentelemetry.io/otel/sdk/metric => ../../sdk/metric
 
 replace go.opentelemetry.io/otel/sdk => ../../sdk
+
+replace go.opentelemetry.io/otel/exporters/stdout/stdoutlog => ../../exporters/stdout/stdoutlog
+
+replace go.opentelemetry.io/otel/log => ../../log
+
+replace go.opentelemetry.io/otel/sdk/log => ../../sdk/log

example/dice/go.sum

@@ -13,8 +13,16 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+go.opentelemetry.io/contrib/bridges/otelslog v0.1.0 h1:XQka5HbIS6JOeZvWz3oKyvzGmMaw7bsHH6r26Kmbrc4=
+go.opentelemetry.io/contrib/bridges/otelslog v0.1.0/go.mod h1:TTRD9H+Ddlxv9NaX+2kQXUGiYAOpcOS0kkTlC1EI4Wg=
 go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.51.0 h1:Xs2Ncz0gNihqu9iosIZ5SkBbWo5T8JhhLJFMQL1qmLI=
 go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.51.0/go.mod h1:vy+2G/6NvVMpwGX/NyLqcC41fxepnuKHk16E6IZUcJc=
+go.opentelemetry.io/otel/exporters/stdout/stdoutlog v0.2.0-alpha h1:CiSTize9+jaVKIBrg0f7TrXwYbcPoNVzEMjZzodjVJg=
+go.opentelemetry.io/otel/exporters/stdout/stdoutlog v0.2.0-alpha/go.mod h1:EHpoV+lMtXn4szUpPuWWLcG+t5HnL09w/WRA7LT3RBE=
+go.opentelemetry.io/otel/log v0.2.0-alpha h1:ixOPvMzserpqA07SENHvRzkZOsnG0XbPr74hv1AQ+n0=
+go.opentelemetry.io/otel/log v0.2.0-alpha/go.mod h1:vbFZc65yq4c4ssvXY43y/nIqkNJLxORrqw0L85P59LA=
+go.opentelemetry.io/otel/sdk/log v0.2.0-alpha h1:jGTkL/jroJ31jnP6jDl34N/mDOfRGGYZHcHsCM+5kWA=
+go.opentelemetry.io/otel/sdk/log v0.2.0-alpha/go.mod h1:Hd8Lw9FPGUM3pfY7iGMRvFaC2Nyau4Ajb5WnQ9OdIho=
 golang.org/x/sys v0.20.0 h1:Od9JTbYCk261bKm4M/mw7AklTlFYIa0bIp9BgSm1S8Y=
 golang.org/x/sys v0.20.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

example/dice/main.go

@@ -78,7 +78,8 @@ func newHTTPHandler() http.Handler {
 	}
 
 	// Register handlers.
-	handleFunc("/rolldice", rolldice)
+	handleFunc("/rolldice/", rolldice)
+	handleFunc("/rolldice/{player}", rolldice)
 
 	// Add HTTP instrumentation for the whole server.
 	handler := otelhttp.NewHandler(mux, "/")

example/dice/otel.go

@@ -9,9 +9,12 @@ import (
 	"time"
 
 	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/exporters/stdout/stdoutlog"
 	"go.opentelemetry.io/otel/exporters/stdout/stdoutmetric"
 	"go.opentelemetry.io/otel/exporters/stdout/stdouttrace"
+	"go.opentelemetry.io/otel/log/global"
 	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel/sdk/log"
 	"go.opentelemetry.io/otel/sdk/metric"
 	"go.opentelemetry.io/otel/sdk/trace"
 )
@@ -60,6 +63,15 @@ func setupOTelSDK(ctx context.Context) (shutdown func(context.Context) error, er
 	shutdownFuncs = append(shutdownFuncs, meterProvider.Shutdown)
 	otel.SetMeterProvider(meterProvider)
 
+	// Set up logger provider.
+	loggerProvider, err := newLoggerProvider()
+	if err != nil {
+		handleErr(err)
+		return
+	}
+	shutdownFuncs = append(shutdownFuncs, loggerProvider.Shutdown)
+	global.SetLoggerProvider(loggerProvider)
+
 	return
 }
 
@@ -98,3 +110,15 @@ func newMeterProvider() (*metric.MeterProvider, error) {
 	)
 	return meterProvider, nil
 }
+
+func newLoggerProvider() (*log.LoggerProvider, error) {
+	logExporter, err := stdoutlog.New()
+	if err != nil {
+		return nil, err
+	}
+
+	meterProvider := log.NewLoggerProvider(
+		log.WithProcessor(log.NewBatchProcessor(logExporter)),
+	)
+	return meterProvider, nil
+}

example/dice/rolldice.go

@@ -4,20 +4,29 @@
 package main
 
 import (
+	"fmt"
 	"io"
-	"log"
 	"math/rand"
 	"net/http"
 	"strconv"
 
+	"go.opentelemetry.io/contrib/bridges/otelslog"
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/sdk/instrumentation"
 )
 
+const name = "rolldice"
+
 var (
-	tracer  = otel.Tracer("rolldice")
-	meter   = otel.Meter("rolldice")
+	tracer = otel.Tracer(name)
+	meter  = otel.Meter(name)
+	logger = otelslog.NewLogger(
+		otelslog.WithInstrumentationScope(instrumentation.Scope{
+			Name: name,
+		}),
+	)
 	rollCnt metric.Int64Counter
 )
 
@@ -37,12 +46,21 @@ func rolldice(w http.ResponseWriter, r *http.Request) {
 
 	roll := 1 + rand.Intn(6)
 
+	player := r.PathValue("player")
+	var msg string
+	if player != "" {
+		msg = fmt.Sprintf("%s is rolling the dice", player)
+	} else {
+		msg = "Anonymous player is rolling the dice"
+	}
+	logger.InfoContext(ctx, msg, "result", roll)
+
 	rollValueAttr := attribute.Int("roll.value", roll)
 	span.SetAttributes(rollValueAttr)
 	rollCnt.Add(ctx, 1, metric.WithAttributes(rollValueAttr))
 
 	resp := strconv.Itoa(roll) + "\n"
 	if _, err := io.WriteString(w, resp); err != nil {
-		log.Printf("Write failed: %v\n", err)
+		logger.ErrorContext(ctx, "Write failed", "error", err)
 	}
 }