[hotrod]: Upgrade redis service to native OTEL instrumentation

## Which problem is this PR solving?

Related to #3380 
Part of #3381 

- This adds `OTEL tracerProvider` and removes `OT tracer` for Redis
service hotROD app

Before:

![r2](https://github.com/jaegertracing/jaeger/assets/11625672/446d03b9-2da0-47b2-9312-b8bc86c7e78a)


After:

![r1](https://github.com/jaegertracing/jaeger/assets/11625672/ed3f2ca6-7a01-4ab2-a13c-56c1f3388fe6)

---------

Signed-off-by: afzal442 <[email protected]>
Co-authored-by: Afzal <[email protected]>

examples/hotrod/pkg/tracing/init.go

@@ -34,6 +34,7 @@ import (
 	"go.opentelemetry.io/otel/sdk/resource"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 	semconv "go.opentelemetry.io/otel/semconv/v1.7.0"
+	"go.opentelemetry.io/otel/trace"
 	"go.uber.org/zap"
 
 	"github.com/jaegertracing/jaeger/examples/hotrod/pkg/log"
@@ -43,9 +44,24 @@ import (
 
 var once sync.Once
 
-// Init initializes OpenTelemetry SDK and uses OTel-OpenTracing Bridge
-// to return an OpenTracing-compatible tracer.
+// InitOTEL initializes OpenTelemetry SDK.
+func InitOTEL(serviceName string, exporterType string, metricsFactory metrics.Factory, logger log.Factory) trace.Tracer {
+	_, oteltp := initBOTH(serviceName, exporterType, metricsFactory, logger)
+
+	logger.Bg().Debug("Created OTEL tracer", zap.String("service-name", serviceName))
+	return oteltp.Tracer(serviceName)
+}
+
+// Init returns OTel-OpenTracing Bridge.
 func Init(serviceName string, exporterType string, metricsFactory metrics.Factory, logger log.Factory) opentracing.Tracer {
+	otTracer, _ := initBOTH(serviceName, exporterType, metricsFactory, logger)
+
+	logger.Bg().Debug("Created OTEL->OT bridge", zap.String("service-name", serviceName))
+	return otTracer
+}
+
+// initBOTH initializes OpenTelemetry SDK and uses OTel-OpenTracing Bridge
+func initBOTH(serviceName string, exporterType string, metricsFactory metrics.Factory, logger log.Factory) (opentracing.Tracer, trace.TracerProvider) {
 	once.Do(func() {
 		otel.SetTextMapPropagator(
 			propagation.NewCompositeTextMapPropagator(
@@ -70,9 +86,8 @@ func Init(serviceName string, exporterType string, metricsFactory metrics.Factor
 			semconv.ServiceNameKey.String(serviceName),
 		)),
 	)
-	otTracer, _ := otbridge.NewTracerPair(tp.Tracer(""))
-	logger.Bg().Debug("created OTEL->OT bridge", zap.String("service-name", serviceName))
-	return otTracer
+	otTracer, _ := otbridge.NewTracerPair(tp.Tracer(serviceName))
+	return otTracer, tp
 }
 
 // withSecure instructs the client to use HTTPS scheme, instead of hotrod's desired default HTTP

examples/hotrod/services/driver/redis.go

@@ -22,8 +22,9 @@ import (
 	"math/rand"
 	"sync"
 
-	"github.com/opentracing/opentracing-go"
-	"github.com/opentracing/opentracing-go/ext"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+	"go.opentelemetry.io/otel/trace"
 	"go.uber.org/zap"
 
 	"github.com/jaegertracing/jaeger/examples/hotrod/pkg/delay"
@@ -35,27 +36,24 @@ import (
 
 // Redis is a simulator of remote Redis cache
 type Redis struct {
-	tracer opentracing.Tracer // simulate redis as a separate process
+	tracer trace.Tracer // simulate redis as a separate process
 	logger log.Factory
 	errorSimulator
 }
 
 func newRedis(otelExporter string, metricsFactory metrics.Factory, logger log.Factory) *Redis {
 	return &Redis{
-		tracer: tracing.Init("redis", otelExporter, metricsFactory, logger),
+		tracer: tracing.InitOTEL("redis-manual", otelExporter, metricsFactory, logger),
 		logger: logger,
 	}
 }
 
 // FindDriverIDs finds IDs of drivers who are near the location.
 func (r *Redis) FindDriverIDs(ctx context.Context, location string) []string {
-	if span := opentracing.SpanFromContext(ctx); span != nil {
-		span := r.tracer.StartSpan("FindDriverIDs", opentracing.ChildOf(span.Context()))
-		span.SetTag("param.location", location)
-		ext.SpanKindRPCClient.Set(span)
-		defer span.Finish()
-		ctx = opentracing.ContextWithSpan(ctx, span)
-	}
+	ctx, span := r.tracer.Start(ctx, "FindDriverIDs", trace.WithSpanKind(trace.SpanKindClient))
+	span.SetAttributes(attribute.Key("param.driver.location").String(location))
+	defer span.End()
+
 	// simulate RPC delay
 	delay.Sleep(config.RedisFindDelay, config.RedisFindDelayStdDev)
 
@@ -70,23 +68,21 @@ func (r *Redis) FindDriverIDs(ctx context.Context, location string) []string {
 
 // GetDriver returns driver and the current car location
 func (r *Redis) GetDriver(ctx context.Context, driverID string) (Driver, error) {
-	if span := opentracing.SpanFromContext(ctx); span != nil {
-		span := r.tracer.StartSpan("GetDriver", opentracing.ChildOf(span.Context()))
-		span.SetTag("param.driverID", driverID)
-		ext.SpanKindRPCClient.Set(span)
-		defer span.Finish()
-		ctx = opentracing.ContextWithSpan(ctx, span)
-	}
+	ctx, span := r.tracer.Start(ctx, "GetDriver", trace.WithSpanKind(trace.SpanKindClient))
+	span.SetAttributes(attribute.Key("param.driverID").String(driverID))
+	defer span.End()
+
 	// simulate RPC delay
 	delay.Sleep(config.RedisGetDelay, config.RedisGetDelayStdDev)
 	if err := r.checkError(); err != nil {
-		if span := opentracing.SpanFromContext(ctx); span != nil {
-			ext.Error.Set(span, true)
-		}
+		span.RecordError(err)
+		span.SetStatus(codes.Error, "An error occurred")
 		r.logger.For(ctx).Error("redis timeout", zap.String("driver_id", driverID), zap.Error(err))
 		return Driver{}, err
 	}
 
+	r.logger.For(ctx).Info("Got driver's ID", zap.String("driverID", driverID))
+
 	// #nosec
 	return Driver{
 		DriverID: driverID,