[hw-7] add metrics, tracing

cart/internal/infra/tracing/otel.go

@@ -0,0 +1,22 @@
+package tracing
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+)
+
+func InitOTLP(ctx context.Context, serviceName, endpoint string) (shutdown func(context.Context) error, err error) {
+	exp, err := otlptracehttp.New(ctx,
+		otlptracehttp.WithEndpoint(endpoint),
+		otlptracehttp.WithInsecure(),
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	NewTracer(serviceName, sdktrace.WithBatcher(exp))
+
+	return Shutdown, nil
+}