VictoriaMetrics/docs/guides/getting-started-with-opentelemetry/app.go-collector.example
Andrii Chubatiuk 77c3bbf3fc
docs: updated guides structure, removed deprecated sort option ()
### Describe Your Changes

* `sort` param is unused by the current website engine, and was present only for compatibility
with previous website engine. It is time to remove it as it makes no effect
* re-structure guides content into folders to simplify assets management

### Checklist

The following checks are **mandatory**:

- [ ] My change adheres [VictoriaMetrics contributing
guidelines](https://docs.victoriametrics.com/contributing/).

(cherry picked from commit 35d77a3bed)
2024-08-07 16:59:22 +02:00

224 lines
5.8 KiB
Plaintext

package main
import (
"context"
"errors"
"io"
"log"
"math/rand"
"net"
"net/http"
"os"
"os/signal"
"strconv"
"time"
"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
"go.opentelemetry.io/otel"
"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp"
"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
"go.opentelemetry.io/otel/propagation"
otelmetric "go.opentelemetry.io/otel/metric"
"go.opentelemetry.io/otel/sdk/metric"
"go.opentelemetry.io/otel/sdk/resource"
"go.opentelemetry.io/otel/sdk/trace"
semconv "go.opentelemetry.io/otel/semconv/v1.25.0"
)
func main() {
if err := run(); err != nil {
log.Fatalln(err)
}
}
func run() (err error) {
// Handle SIGINT (CTRL+C) gracefully.
ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
defer stop()
// Set up OpenTelemetry.
otelShutdown, err := setupOTelSDK(ctx)
if err != nil {
return
}
// Handle shutdown properly so nothing leaks.
defer func() {
err = errors.Join(err, otelShutdown(context.Background()))
}()
// Start HTTP server.
srv := &http.Server{
Addr: ":8080",
BaseContext: func(_ net.Listener) context.Context { return ctx },
ReadTimeout: time.Second,
WriteTimeout: 10 * time.Second,
Handler: newHTTPHandler(),
}
srvErr := make(chan error, 1)
go func() {
srvErr <- srv.ListenAndServe()
}()
// Wait for interruption.
select {
case err = <-srvErr:
// Error when starting HTTP server.
return
case <-ctx.Done():
// Wait for first CTRL+C.
// Stop receiving signal notifications as soon as possible.
stop()
}
// When Shutdown is called, ListenAndServe immediately returns ErrServerClosed.
err = srv.Shutdown(context.Background())
return
}
func newHTTPHandler() http.Handler {
mux := http.NewServeMux()
// handleFunc is a replacement for mux.HandleFunc
// which enriches the handler's HTTP instrumentation with the pattern as the http.route.
handleFunc := func(pattern string, handlerFunc func(http.ResponseWriter, *http.Request)) {
// Configure the "http.route" for the HTTP instrumentation.
handler := otelhttp.WithRouteTag(pattern, http.HandlerFunc(handlerFunc))
mux.Handle(pattern, handler)
}
// Register handlers.
handleFunc("/rolldice", rolldice)
// Add HTTP instrumentation for the whole server.
handler := otelhttp.NewHandler(mux, "/")
return handler
}
var (
tracer = otel.Tracer("rolldice")
meter = otel.Meter("rolldice")
rollCnt otelmetric.Int64Counter
)
func init() {
var err error
rollCnt, err = meter.Int64Counter("dice.rolls",
otelmetric.WithDescription("The number of rolls by roll value"),
otelmetric.WithUnit("{roll}"))
if err != nil {
panic(err)
}
}
func rolldice(w http.ResponseWriter, r *http.Request) {
ctx, span := tracer.Start(r.Context(), "roll")
defer span.End()
roll := 1 + rand.Intn(6)
rollValueAttr := attribute.Int("roll.value", roll)
span.SetAttributes(rollValueAttr)
rollCnt.Add(ctx, 1, otelmetric.WithAttributes(rollValueAttr))
resp := strconv.Itoa(roll) + "\n"
if _, err := io.WriteString(w, resp); err != nil {
log.Printf("Write failed: %v\n", err)
}
}
// setupOTelSDK bootstraps the OpenTelemetry pipeline.
// If it does not return an error, make sure to call shutdown for proper cleanup.
func setupOTelSDK(ctx context.Context) (shutdown func(context.Context) error, err error) {
var shutdownFuncs []func(context.Context) error
// shutdown calls cleanup functions registered via shutdownFuncs.
// The errors from the calls are joined.
// Each registered cleanup will be invoked once.
shutdown = func(ctx context.Context) error {
var err error
for _, fn := range shutdownFuncs {
err = errors.Join(err, fn(ctx))
}
shutdownFuncs = nil
return err
}
// handleErr calls shutdown for cleanup and makes sure that all errors are returned.
handleErr := func(inErr error) {
err = errors.Join(inErr, shutdown(ctx))
}
// Set up propagator.
prop := newPropagator()
otel.SetTextMapPropagator(prop)
// Set up trace provider.
tracerProvider, err := newTraceProvider(ctx)
if err != nil {
handleErr(err)
return
}
shutdownFuncs = append(shutdownFuncs, tracerProvider.Shutdown)
otel.SetTracerProvider(tracerProvider)
// Set up meter provider.
meterProvider, err := newMeterProvider(ctx)
if err != nil {
handleErr(err)
return
}
shutdownFuncs = append(shutdownFuncs, meterProvider.Shutdown)
otel.SetMeterProvider(meterProvider)
return
}
func newPropagator() propagation.TextMapPropagator {
return propagation.NewCompositeTextMapPropagator(
propagation.TraceContext{},
propagation.Baggage{},
)
}
func newTraceProvider(ctx context.Context) (*trace.TracerProvider, error) {
traceExporter, err := otlptracehttp.New(ctx, otlptracehttp.WithInsecure(), otlptracehttp.WithEndpoint("localhost:4318"))
if err != nil {
return nil, err
}
traceProvider := trace.NewTracerProvider(
trace.WithBatcher(traceExporter,
// Default is 5s. Set to 1s for demonstrative purposes.
trace.WithBatchTimeout(time.Second)),
)
return traceProvider, nil
}
func newMeterProvider(ctx context.Context) (*metric.MeterProvider, error) {
metricExporter, err := otlpmetrichttp.New(ctx, otlpmetrichttp.WithInsecure(), otlpmetrichttp.WithEndpoint("localhost:4318"))
if err != nil {
return nil, err
}
//metricExporter, err := stdoutmetric.New()
//if err != nil {
// return nil, err
//}
res, err := resource.Merge(resource.Default(),
resource.NewWithAttributes(semconv.SchemaURL,
semconv.ServiceName("dice-roller"),
semconv.ServiceVersion("0.1.0"),
))
if err != nil {
return nil, err
}
meterProvider := metric.NewMeterProvider(
metric.WithResource(res),
metric.WithReader(metric.NewPeriodicReader(metricExporter,
// Default is 1m. Set to 3s for demonstrative purposes.
metric.WithInterval(3*time.Second))),
)
return meterProvider, nil
}