Add k8s resource attributes automatically

Co-authored-by: Romain <rtribotte@users.noreply.github.com>

cmd/traefik/logger.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"io"
@@ -22,7 +23,7 @@ func init() {
 	zerolog.SetGlobalLevel(zerolog.ErrorLevel)
 }
 
-func setupLogger(staticConfiguration *static.Configuration) error {
+func setupLogger(ctx context.Context, staticConfiguration *static.Configuration) error {
 	// Validate that the experimental flag is set up at this point,
 	// rather than validating the static configuration before the setupLogger call.
 	// This ensures that validation messages are not logged using an un-configured logger.
@@ -39,16 +40,16 @@ func setupLogger(staticConfiguration *static.Configuration) error {
 	zerolog.SetGlobalLevel(logLevel)
 
 	// create logger
-	logCtx := zerolog.New(w).With().Timestamp()
+	logger := zerolog.New(w).With().Timestamp()
 	if logLevel <= zerolog.DebugLevel {
-		logCtx = logCtx.Caller()
+		logger = logger.Caller()
 	}
 
-	log.Logger = logCtx.Logger().Level(logLevel)
+	log.Logger = logger.Logger().Level(logLevel)
 
 	if staticConfiguration.Log != nil && staticConfiguration.Log.OTLP != nil {
 		var err error
-		log.Logger, err = logs.SetupOTelLogger(log.Logger, staticConfiguration.Log.OTLP)
+		log.Logger, err = logs.SetupOTelLogger(ctx, log.Logger, staticConfiguration.Log.OTLP)
 		if err != nil {
 			return fmt.Errorf("setting up OpenTelemetry logger: %w", err)
 		}

cmd/traefik/traefik.go

@@ -90,7 +90,10 @@ Complete documentation is available at https://traefik.io`,
 }
 
 func runCmd(staticConfiguration *static.Configuration) error {
-	if err := setupLogger(staticConfiguration); err != nil {
+	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer cancel()
+
+	if err := setupLogger(ctx, staticConfiguration); err != nil {
 		return fmt.Errorf("setting up logger: %w", err)
 	}
 
@@ -123,8 +126,6 @@ func runCmd(staticConfiguration *static.Configuration) error {
 		return err
 	}
 
-	ctx, _ := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
-
 	if staticConfiguration.Ping != nil {
 		staticConfiguration.Ping.WithContext(ctx)
 	}
@@ -210,8 +211,8 @@ func setupServer(staticConfiguration *static.Configuration) (*server.Server, err
 		}
 	}
 	metricsRegistry := metrics.NewMultiRegistry(metricRegistries)
-	accessLog := setupAccessLog(staticConfiguration.AccessLog)
+	accessLog := setupAccessLog(ctx, staticConfiguration.AccessLog)
-	tracer, tracerCloser := setupTracing(staticConfiguration.Tracing)
+	tracer, tracerCloser := setupTracing(ctx, staticConfiguration.Tracing)
 	observabilityMgr := middleware.NewObservabilityMgr(*staticConfiguration, metricsRegistry, semConvMetricRegistry, accessLog, tracer, tracerCloser)
 
 	// Entrypoints
@@ -586,12 +587,12 @@ func appendCertMetric(gauge gokitmetrics.Gauge, certificate *x509.Certificate) {
 	gauge.With(labels...).Set(notAfter)
 }
 
-func setupAccessLog(conf *types.AccessLog) *accesslog.Handler {
+func setupAccessLog(ctx context.Context, conf *types.AccessLog) *accesslog.Handler {
 	if conf == nil {
 		return nil
 	}
 
-	accessLoggerMiddleware, err := accesslog.NewHandler(conf)
+	accessLoggerMiddleware, err := accesslog.NewHandler(ctx, conf)
 	if err != nil {
 		log.Warn().Err(err).Msg("Unable to create access logger")
 		return nil
@@ -600,12 +601,12 @@ func setupAccessLog(conf *types.AccessLog) *accesslog.Handler {
 	return accessLoggerMiddleware
 }
 
-func setupTracing(conf *static.Tracing) (*tracing.Tracer, io.Closer) {
+func setupTracing(ctx context.Context, conf *static.Tracing) (*tracing.Tracer, io.Closer) {
 	if conf == nil {
 		return nil, nil
 	}
 
-	tracer, closer, err := tracing.NewTracing(conf)
+	tracer, closer, err := tracing.NewTracing(ctx, conf)
 	if err != nil {
 		log.Warn().Err(err).Msg("Unable to create tracer")
 		return nil, nil

docs/content/migration/v3.md

@@ -322,9 +322,11 @@ and Traefik now keeps them encoded to avoid any ambiguity.
 
 ## v3.5.0
 
-### TraceVerbosity on Routers and Entrypoints
+### Observability
 
-Starting with v3.5, a new `traceVerbosity` option is available for both entrypoints and routers.
+#### TraceVerbosity on Routers and Entrypoints
+
+Starting with `v3.5.0`, a new `traceVerbosity` option is available for both entrypoints and routers.
 This option allows you to control the level of detail for tracing spans.
 Routers can override the value inherited from their entrypoint.
 
@@ -339,3 +341,20 @@ Possible values are:
 - `detailed`: enables the creation of additional spans for each middleware executed for each request processed by a router.
 
 See the updated documentation for [entrypoints](../reference/install-configuration/entrypoints.md) and [dynamic routers](../reference/dynamic-configuration/file.md#observability-options).
+
+#### K8s Resource Attributes
+
+Since `v3.5.0`, the semconv attributes `k8s.pod.name` and `k8s.pod.uid` are injected automatically in OTel resource attributes when OTel tracing/logs/metrics are enabled.
+
+For that purpose, the following right has to be added to the Traefik Kubernetes RBACs:
+
+```yaml
+  ...
+  - apiGroups:
+      - ""
+    resources:
+      - pods
+    verbs:
+      - get
+  ...
+```

docs/content/reference/dynamic-configuration/kubernetes-crd-rbac.yml

@@ -15,6 +15,14 @@ rules:
       - get
       - list
       - watch
+  # The pods right is needed to inject k8s.pod.uid and k8s.pod.name OTel attributes.
+  # When OTel tracing/logs/metrics are not enabled, this rule is not needed.
+  - apiGroups:
+      - ""
+    resources:
+       - pods
+    verbs:
+        - get
   - apiGroups:
       - discovery.k8s.io
     resources:

docs/content/reference/dynamic-configuration/kubernetes-gateway-rbac.yml

@@ -11,6 +11,14 @@ rules:
     verbs:
       - list
       - watch
+  # The pods get right is needed to inject k8s.pod.uid and k8s.pod.name in OTel attributes.
+  # When OTel tracing/logs/metrics are not enabled, this rule is not needed.
+  - apiGroups:
+      - ""
+    resources:
+      - pods
+    verbs:
+      - get
   - apiGroups:
       - ""
     resources:

pkg/logs/otel.go

@@ -1,6 +1,7 @@
 package logs
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"reflect"
@@ -12,12 +13,12 @@ import (
 )
 
 // SetupOTelLogger sets up the OpenTelemetry logger.
-func SetupOTelLogger(logger zerolog.Logger, config *types.OTelLog) (zerolog.Logger, error) {
+func SetupOTelLogger(ctx context.Context, logger zerolog.Logger, config *types.OTelLog) (zerolog.Logger, error) {
 	if config == nil {
 		return logger, nil
 	}
 
-	provider, err := config.NewLoggerProvider()
+	provider, err := config.NewLoggerProvider(ctx)
 	if err != nil {
 		return zerolog.Logger{}, fmt.Errorf("setting up OpenTelemetry logger provider: %w", err)
 	}

pkg/logs/otel_test.go

@@ -171,7 +171,7 @@ func TestLog(t *testing.T) {
 			out := zerolog.MultiLevelWriter(zerolog.ConsoleWriter{Out: os.Stderr, TimeFormat: time.RFC3339})
 			logger := zerolog.New(out).With().Caller().Logger()
 
-			logger, err := SetupOTelLogger(logger, config)
+			logger, err := SetupOTelLogger(t.Context(), logger, config)
 			require.NoError(t, err)
 
 			ctx := trace.ContextWithSpanContext(t.Context(), trace.NewSpanContext(trace.SpanContextConfig{

pkg/metrics/otel.go

@@ -217,6 +217,7 @@ func newOpenTelemetryMeterProvider(ctx context.Context, config *types.OTLP) (*sd
 		resource.WithOS(),
 		resource.WithProcess(),
 		resource.WithTelemetrySDK(),
+		resource.WithDetectors(types.K8sAttributesDetector{}),
 		// The following order allows the user to override the service name and version,
 		// as well as any other attributes set by the above detectors.
 		resource.WithAttributes(

pkg/middlewares/accesslog/logger.go

@@ -85,7 +85,7 @@ func (h *Handler) AliceConstructor() alice.Constructor {
 }
 
 // NewHandler creates a new Handler.
-func NewHandler(config *types.AccessLog) (*Handler, error) {
+func NewHandler(ctx context.Context, config *types.AccessLog) (*Handler, error) {
 	var file io.WriteCloser = noopCloser{os.Stdout}
 	if len(config.FilePath) > 0 {
 		f, err := openAccessLogFile(config.FilePath)
@@ -116,7 +116,7 @@ func NewHandler(config *types.AccessLog) (*Handler, error) {
 	}
 
 	if config.OTLP != nil {
-		otelLoggerProvider, err := config.OTLP.NewLoggerProvider()
+		otelLoggerProvider, err := config.OTLP.NewLoggerProvider(ctx)
 		if err != nil {
 			return nil, fmt.Errorf("setting up OpenTelemetry logger provider: %w", err)
 		}

pkg/middlewares/accesslog/logger_test.go

@@ -85,7 +85,7 @@ func TestOTelAccessLog(t *testing.T) {
 			},
 		},
 	}
-	logHandler, err := NewHandler(config)
+	logHandler, err := NewHandler(t.Context(), config)
 	require.NoError(t, err)
 	t.Cleanup(func() {
 		err := logHandler.Close()
@@ -138,7 +138,7 @@ func TestLogRotation(t *testing.T) {
 	rotatedFileName := fileName + ".rotated"
 
 	config := &types.AccessLog{FilePath: fileName, Format: CommonFormat}
-	logHandler, err := NewHandler(config)
+	logHandler, err := NewHandler(t.Context(), config)
 	require.NoError(t, err)
 	t.Cleanup(func() {
 		err := logHandler.Close()
@@ -282,7 +282,7 @@ func TestLoggerHeaderFields(t *testing.T) {
 				Fields:   &test.accessLogFields,
 			}
 
-			logger, err := NewHandler(config)
+			logger, err := NewHandler(t.Context(), config)
 			require.NoError(t, err)
 			t.Cleanup(func() {
 				err := logger.Close()
@@ -979,7 +979,7 @@ func captureStdout(t *testing.T) (out *os.File, restoreStdout func()) {
 
 func doLoggingTLSOpt(t *testing.T, config *types.AccessLog, enableTLS, tracing bool) {
 	t.Helper()
-	logger, err := NewHandler(config)
+	logger, err := NewHandler(t.Context(), config)
 	require.NoError(t, err)
 	t.Cleanup(func() {
 		err := logger.Close()
@@ -1076,7 +1076,7 @@ func logWriterTestHandlerFunc(rw http.ResponseWriter, r *http.Request) {
 func doLoggingWithAbortedStream(t *testing.T, config *types.AccessLog) {
 	t.Helper()
 
-	logger, err := NewHandler(config)
+	logger, err := NewHandler(t.Context(), config)
 	require.NoError(t, err)
 	t.Cleanup(func() {
 		err := logger.Close()

pkg/tracing/tracing.go

@@ -25,11 +25,11 @@ import (
 
 // Backend is an abstraction for tracking backend (OpenTelemetry, ...).
 type Backend interface {
-	Setup(serviceName string, sampleRate float64, resourceAttributes map[string]string) (trace.Tracer, io.Closer, error)
+	Setup(ctx context.Context, serviceName string, sampleRate float64, resourceAttributes map[string]string) (trace.Tracer, io.Closer, error)
 }
 
 // NewTracing Creates a Tracing.
-func NewTracing(conf *static.Tracing) (*Tracer, io.Closer, error) {
+func NewTracing(ctx context.Context, conf *static.Tracing) (*Tracer, io.Closer, error) {
 	var backend Backend
 
 	if conf.OTLP != nil {
@@ -44,7 +44,7 @@ func NewTracing(conf *static.Tracing) (*Tracer, io.Closer, error) {
 
 	otel.SetTextMapPropagator(autoprop.NewTextMapPropagator())
 
-	tr, closer, err := backend.Setup(conf.ServiceName, conf.SampleRate, conf.ResourceAttributes)
+	tr, closer, err := backend.Setup(ctx, conf.ServiceName, conf.SampleRate, conf.ResourceAttributes)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -84,13 +84,6 @@ func InjectContextIntoCarrier(req *http.Request) {
 	propagator.Inject(req.Context(), propagation.HeaderCarrier(req.Header))
 }
 
-// SetStatusErrorf flags the span as in error and log an event.
-func SetStatusErrorf(ctx context.Context, format string, args ...interface{}) {
-	if span := trace.SpanFromContext(ctx); span != nil {
-		span.SetStatus(codes.Error, fmt.Sprintf(format, args...))
-	}
-}
-
 // Span is trace.Span wrapping the Traefik TracerProvider.
 type Span struct {
 	trace.Span

pkg/tracing/tracing_test.go

@@ -350,7 +350,7 @@ func TestTracing(t *testing.T) {
 				},
 			}
 
-			tracer, closer, err := NewTracing(tracingConfig)
+			tracer, closer, err := NewTracing(t.Context(), tracingConfig)
 			require.NoError(t, err)
 			t.Cleanup(func() {
 				_ = closer.Close()
@@ -402,7 +402,7 @@ func TestTracerProvider(t *testing.T) {
 	otlpConfig.SetDefaults()
 
 	config := &static.Tracing{OTLP: otlpConfig}
-	tracer, closer, err := NewTracing(config)
+	tracer, closer, err := NewTracing(t.Context(), config)
 	if err != nil {
 		t.Fatal(err)
 	}

pkg/types/k8sdetector.go

@@ -0,0 +1,70 @@
+package types
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/rs/zerolog/log"
+	"go.opentelemetry.io/otel/sdk/resource"
+	semconv "go.opentelemetry.io/otel/semconv/v1.26.0"
+	kerror "k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	kclientset "k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/rest"
+)
+
+// K8sAttributesDetector detects the metadata of the Traefik pod running in a Kubernetes cluster.
+// It reads the pod name from the hostname file and the namespace from the service account namespace file and queries the Kubernetes API to get the pod's UID.
+type K8sAttributesDetector struct{}
+
+func (K8sAttributesDetector) Detect(ctx context.Context) (*resource.Resource, error) {
+	attrs := os.Getenv("OTEL_RESOURCE_ATTRIBUTES")
+	if strings.Contains(attrs, string(semconv.K8SPodNameKey)) || strings.Contains(attrs, string(semconv.K8SPodUIDKey)) {
+		return resource.Empty(), nil
+	}
+
+	// The InClusterConfig function returns a config for the Kubernetes API server
+	// when it is running inside a Kubernetes cluster.
+	config, err := rest.InClusterConfig()
+	if err != nil && errors.Is(err, rest.ErrNotInCluster) {
+		return resource.Empty(), nil
+	}
+	if err != nil {
+		return nil, fmt.Errorf("creating in cluster config: %w", err)
+	}
+
+	client, err := kclientset.NewForConfig(config)
+	if err != nil {
+		return nil, fmt.Errorf("creating Kubernetes client: %w", err)
+	}
+
+	podName, err := os.Hostname()
+	if err != nil {
+		return nil, fmt.Errorf("getting pod name: %w", err)
+	}
+
+	podNamespaceBytes, err := os.ReadFile("/var/run/secrets/kubernetes.io/serviceaccount/namespace")
+	if err != nil {
+		return nil, fmt.Errorf("getting pod namespace: %w", err)
+	}
+	podNamespace := string(podNamespaceBytes)
+
+	pod, err := client.CoreV1().Pods(podNamespace).Get(ctx, podName, metav1.GetOptions{})
+	if err != nil && kerror.IsForbidden(err) {
+		log.Error().Err(err).Msg("Unable to build K8s resource attributes for Traefik pod")
+		return resource.Empty(), nil
+	}
+	if err != nil {
+		return nil, fmt.Errorf("getting pod metadata: %w", err)
+	}
+
+	// To avoid version conflicts with other detectors, we use a Schemaless resource.
+	return resource.NewSchemaless(
+		semconv.K8SPodUID(string(pod.UID)),
+		semconv.K8SPodName(pod.Name),
+		semconv.K8SNamespaceName(podNamespace),
+	), nil
+}

pkg/types/logs.go

@@ -13,7 +13,7 @@ import (
 	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp"
 	otelsdk "go.opentelemetry.io/otel/sdk/log"
 	"go.opentelemetry.io/otel/sdk/resource"
-	semconv "go.opentelemetry.io/otel/semconv/v1.27.0"
+	semconv "go.opentelemetry.io/otel/semconv/v1.26.0"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/encoding/gzip"
 )
@@ -164,7 +164,7 @@ func (o *OTelLog) SetDefaults() {
 }
 
 // NewLoggerProvider creates a new OpenTelemetry logger provider.
-func (o *OTelLog) NewLoggerProvider() (*otelsdk.LoggerProvider, error) {
+func (o *OTelLog) NewLoggerProvider(ctx context.Context) (*otelsdk.LoggerProvider, error) {
 	var (
 		err      error
 		exporter otelsdk.Exporter
@@ -178,23 +178,27 @@ func (o *OTelLog) NewLoggerProvider() (*otelsdk.LoggerProvider, error) {
 		return nil, fmt.Errorf("setting up exporter: %w", err)
 	}
 
-	attr := []attribute.KeyValue{
+	var resAttrs []attribute.KeyValue
-		semconv.ServiceNameKey.String(o.ServiceName),
-		semconv.ServiceVersionKey.String(version.Version),
-	}
-
 	for k, v := range o.ResourceAttributes {
-		attr = append(attr, attribute.String(k, v))
+		resAttrs = append(resAttrs, attribute.String(k, v))
 	}
 
-	res, err := resource.New(context.Background(),
+	res, err := resource.New(ctx,
-		resource.WithAttributes(attr...),
 		resource.WithContainer(),
-		resource.WithFromEnv(),
 		resource.WithHost(),
 		resource.WithOS(),
 		resource.WithProcess(),
 		resource.WithTelemetrySDK(),
+		resource.WithDetectors(K8sAttributesDetector{}),
+		// The following order allows the user to override the service name and version,
+		// as well as any other attributes set by the above detectors.
+		resource.WithAttributes(
+			semconv.ServiceName(o.ServiceName),
+			semconv.ServiceVersion(version.Version),
+		),
+		resource.WithAttributes(resAttrs...),
+		// Use the environment variables to allow overriding above resource attributes.
+		resource.WithFromEnv(),
 	)
 	if err != nil {
 		return nil, fmt.Errorf("building resource: %w", err)

pkg/types/tracing.go

@@ -17,7 +17,7 @@ import (
 	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
 	"go.opentelemetry.io/otel/sdk/resource"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
-	semconv "go.opentelemetry.io/otel/semconv/v1.27.0"
+	semconv "go.opentelemetry.io/otel/semconv/v1.26.0"
 	"go.opentelemetry.io/otel/trace"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/encoding/gzip"
@@ -52,7 +52,7 @@ func (c *OTelTracing) SetDefaults() {
 }
 
 // Setup sets up the tracer.
-func (c *OTelTracing) Setup(serviceName string, sampleRate float64, resourceAttributes map[string]string) (trace.Tracer, io.Closer, error) {
+func (c *OTelTracing) Setup(ctx context.Context, serviceName string, sampleRate float64, resourceAttributes map[string]string) (trace.Tracer, io.Closer, error) {
 	var (
 		err      error
 		exporter *otlptrace.Exporter
@@ -66,23 +66,27 @@ func (c *OTelTracing) Setup(serviceName string, sampleRate float64, resourceAttr
 		return nil, nil, fmt.Errorf("setting up exporter: %w", err)
 	}
 
-	attr := []attribute.KeyValue{
+	var resAttrs []attribute.KeyValue
-		semconv.ServiceNameKey.String(serviceName),
-		semconv.ServiceVersionKey.String(version.Version),
-	}
-
 	for k, v := range resourceAttributes {
-		attr = append(attr, attribute.String(k, v))
+		resAttrs = append(resAttrs, attribute.String(k, v))
 	}
 
-	res, err := resource.New(context.Background(),
+	res, err := resource.New(ctx,
-		resource.WithAttributes(attr...),
 		resource.WithContainer(),
-		resource.WithFromEnv(),
 		resource.WithHost(),
 		resource.WithOS(),
 		resource.WithProcess(),
 		resource.WithTelemetrySDK(),
+		resource.WithDetectors(K8sAttributesDetector{}),
+		// The following order allows the user to override the service name and version,
+		// as well as any other attributes set by the above detectors.
+		resource.WithAttributes(
+			semconv.ServiceName(serviceName),
+			semconv.ServiceVersion(version.Version),
+		),
+		resource.WithAttributes(resAttrs...),
+		// Use the environment variables to allow overriding above resource attributes.
+		resource.WithFromEnv(),
 	)
 	if err != nil {
 		return nil, nil, fmt.Errorf("building resource: %w", err)