wip

04-manual-instrumentation.md

@@ -1,40 +1,32 @@
 # Manual instrumentation using the OpenTelemetry SDK
 
-# Register Tracer
+This tutorial section covers the manual instrumentation of a go application with the opentelemetry-sdk.
 
-```go
-var tracer = otel.GetTracerProvider().Tracer("github.com/kubecon-eu-2024/backend")
-```
+As a basis for the instrumentation we use [backend4](./app/backend4/main.go). To compile the application you need [go 1.22 or newer](https://go.dev/doc/install).
 
+# Configure OpenTelemetry-go-sdk
 
-# init
+```diff
+func main() {
++	otelExporter, err := otlptracegrpc.New(context.Background())
++	if err != nil {
++		fmt.Printf("failed to create trace exporter: %s\n", err)
++		os.Exit(1)
++	}
++	tp := sdktrace.NewTracerProvider(sdktrace.WithBatcher(otelExporter))
++	otel.SetTracerProvider(tp)
+...
+```
 
-```go
-	var otlpAddr = flag.String("otlp-grpc", "", "default otlp/gRPC address, by default disabled. Example value: localhost:4317")
-	flag.Parse()
-	if *otlpAddr != "" {
-		ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
-		defer cancel()
 
-		grpcOptions := []grpc.DialOption{grpc.WithTransportCredentials(insecure.NewCredentials()), grpc.WithBlock()}
-		conn, err := grpc.DialContext(ctx, *otlpAddr, grpcOptions...)
-		if err != nil {
-			fmt.Printf("failed to create gRPC connection to collector: %s\n", err)
-			os.Exit(1)
-		}
-		defer conn.Close()
+## Create and register a global trace provider
 
-		// Set up a trace exporter
-		otelExporter, err := otlptracegrpc.New(ctx, otlptracegrpc.WithGRPCConn(conn))
-		if err != nil {
-			fmt.Printf("failed to create trace exporter: %s\n", err)
-			os.Exit(1)
-		}
-		tp := sdktrace.NewTracerProvider(sdktrace.WithSyncer(otelExporter))
-		otel.SetTracerProvider(tp)
-	}
+```diff
++var tracer = otel.GetTracerProvider().Tracer("github.com/kubecon-eu-2024/backend")
 ```
 
+## Identifying critical path and operations for instrumentation
+
 ```diff
 	mux.HandleFunc("GET /rolldice", func(w http.ResponseWriter, r *http.Request) {
 +		var span trace.Span
@@ -76,6 +68,16 @@ func causeDelay(ctx context.Context, rate int) {
 }
 ```
 
+## Configuring an OTLP exporter and setting the endpoint
+
+```bash
+ocker run --rm -it -p 127.0.0.1:4317:4317 -p 127.0.0.1:16686:16686 -e COLLECTOR_OTLP_ENABLED=true -e LOG_LEVEL=debug  jaegertracing/all-in-one:latest
+```
+
+```bash
+OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4317 OTEL_SERVICE_NAME=go-backend go run app/backend4/main.go
+```
+
 ---
 
 [Next steps](./05-sampling.md)

app/backend4/main.go

@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"crypto/sha256"
-	"flag"
 	"fmt"
 	"math/rand"
 	"net/http"
@@ -17,8 +16,6 @@ import (
 	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 	"go.opentelemetry.io/otel/trace"
-	"google.golang.org/grpc"
-	"google.golang.org/grpc/credentials/insecure"
 )
 
 var tracer = otel.GetTracerProvider().Tracer("github.com/kubecon-eu-2024/backend")
@@ -46,29 +43,14 @@ func init() {
 }
 
 func main() {
-	var otlpAddr = flag.String("otlp-grpc", "", "default otlp/gRPC address, by default disabled. Example value: localhost:4317")
-	flag.Parse()
-	if *otlpAddr != "" {
-		ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
-		defer cancel()
-
-		grpcOptions := []grpc.DialOption{grpc.WithTransportCredentials(insecure.NewCredentials()), grpc.WithBlock()}
-		conn, err := grpc.DialContext(ctx, *otlpAddr, grpcOptions...)
-		if err != nil {
-			fmt.Printf("failed to create gRPC connection to collector: %s\n", err)
-			os.Exit(1)
-		}
-		defer conn.Close()
-
-		// Set up a trace exporter
-		otelExporter, err := otlptracegrpc.New(ctx, otlptracegrpc.WithGRPCConn(conn))
-		if err != nil {
-			fmt.Printf("failed to create trace exporter: %s\n", err)
-			os.Exit(1)
-		}
-		tp := sdktrace.NewTracerProvider(sdktrace.WithSyncer(otelExporter))
-		otel.SetTracerProvider(tp)
+	otelExporter, err := otlptracegrpc.New(context.Background())
+	if err != nil {
+		fmt.Printf("failed to create trace exporter: %s\n", err)
+		os.Exit(1)
 	}
+	tp := sdktrace.NewTracerProvider(sdktrace.WithBatcher(otelExporter))
+	otel.SetTracerProvider(tp)
+
 	v, ok := os.LookupEnv("ERROR_RATE")
 	if !ok {
 		v = "0"