traefik/pkg/tracing/tracing.go

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package tracing
import (
"context"
"fmt"
"io"
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"net"
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"net/http"
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"strconv"
"strings"
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"github.com/rs/zerolog/log"
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"github.com/traefik/traefik/v3/pkg/config/static"
"github.com/traefik/traefik/v3/pkg/tracing/opentelemetry"
"go.opentelemetry.io/contrib/propagators/autoprop"
"go.opentelemetry.io/otel"
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"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/codes"
"go.opentelemetry.io/otel/propagation"
semconv "go.opentelemetry.io/otel/semconv/v1.21.0"
"go.opentelemetry.io/otel/trace"
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)
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// Backend is an abstraction for tracking backend (OpenTelemetry, ...).
type Backend interface {
Setup(serviceName string, sampleRate float64, globalAttributes map[string]string) (trace.Tracer, io.Closer, error)
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}
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// NewTracing Creates a Tracing.
func NewTracing(conf *static.Tracing) (*Tracer, io.Closer, error) {
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var backend Backend
if conf.OTLP != nil {
backend = conf.OTLP
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}
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if backend == nil {
log.Debug().Msg("Could not initialize tracing, using OpenTelemetry by default")
defaultBackend := &opentelemetry.Config{}
backend = defaultBackend
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}
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otel.SetTextMapPropagator(autoprop.NewTextMapPropagator())
tr, closer, err := backend.Setup(conf.ServiceName, conf.SampleRate, conf.GlobalAttributes)
if err != nil {
return nil, nil, err
}
return NewTracer(tr, conf.CapturedRequestHeaders, conf.CapturedResponseHeaders), closer, nil
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}
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// TracerFromContext extracts the trace.Tracer from the given context.
func TracerFromContext(ctx context.Context) *Tracer {
// Prevent picking trace.noopSpan tracer.
if !trace.SpanContextFromContext(ctx).IsValid() {
return nil
}
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span := trace.SpanFromContext(ctx)
if span != nil && span.TracerProvider() != nil {
tracer := span.TracerProvider().Tracer("github.com/traefik/traefik")
if tracer, ok := tracer.(*Tracer); ok {
return tracer
}
return nil
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}
return nil
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}
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// ExtractCarrierIntoContext reads cross-cutting concerns from the carrier into a Context.
func ExtractCarrierIntoContext(ctx context.Context, headers http.Header) context.Context {
propagator := otel.GetTextMapPropagator()
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return propagator.Extract(ctx, propagation.HeaderCarrier(headers))
}
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// InjectContextIntoCarrier sets cross-cutting concerns from the request context into the request headers.
func InjectContextIntoCarrier(req *http.Request) {
propagator := otel.GetTextMapPropagator()
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propagator.Inject(req.Context(), propagation.HeaderCarrier(req.Header))
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}
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// 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...))
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}
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}
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// Span is trace.Span wrapping the Traefik TracerProvider.
type Span struct {
trace.Span
tracerProvider *TracerProvider
}
// TracerProvider returns the span's TraceProvider.
func (s Span) TracerProvider() trace.TracerProvider {
return s.tracerProvider
}
// TracerProvider is trace.TracerProvider wrapping the Traefik Tracer implementation.
type TracerProvider struct {
trace.TracerProvider
tracer *Tracer
}
// Tracer returns the trace.Tracer for the given options.
// It returns specifically the Traefik Tracer when requested.
func (t TracerProvider) Tracer(name string, options ...trace.TracerOption) trace.Tracer {
if name == "github.com/traefik/traefik" {
return t.tracer
}
return t.TracerProvider.Tracer(name, options...)
}
// Tracer is trace.Tracer with additional properties.
type Tracer struct {
trace.Tracer
capturedRequestHeaders []string
capturedResponseHeaders []string
}
// NewTracer builds and configures a new Tracer.
func NewTracer(tracer trace.Tracer, capturedRequestHeaders, capturedResponseHeaders []string) *Tracer {
return &Tracer{
Tracer: tracer,
capturedRequestHeaders: capturedRequestHeaders,
capturedResponseHeaders: capturedResponseHeaders,
}
}
// Start starts a new span.
// spancheck linter complains about span.End not being called, but this is expected here,
// hence its deactivation.
//
//nolint:spancheck
func (t *Tracer) Start(ctx context.Context, spanName string, opts ...trace.SpanStartOption) (context.Context, trace.Span) {
if t == nil {
return ctx, nil
}
spanCtx, span := t.Tracer.Start(ctx, spanName, opts...)
wrappedSpan := &Span{Span: span, tracerProvider: &TracerProvider{tracer: t}}
return trace.ContextWithSpan(spanCtx, wrappedSpan), wrappedSpan
}
// CaptureClientRequest used to add span attributes from the request as a Client.
// TODO: need to update the semconv package as it does not implement fully Semantic Convention v1.23.0.
func (t *Tracer) CaptureClientRequest(span trace.Span, r *http.Request) {
if t == nil || span == nil || r == nil {
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return
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}
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// Common attributes https://github.com/open-telemetry/semantic-conventions/blob/v1.23.0/docs/http/http-spans.md#common-attributes
span.SetAttributes(semconv.HTTPRequestMethodKey.String(r.Method))
span.SetAttributes(semconv.NetworkProtocolVersion(proto(r.Proto)))
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// Client attributes https://github.com/open-telemetry/semantic-conventions/blob/v1.23.0/docs/http/http-spans.md#http-client
span.SetAttributes(semconv.URLFull(r.URL.String()))
span.SetAttributes(semconv.URLScheme(r.URL.Scheme))
span.SetAttributes(semconv.UserAgentOriginal(r.UserAgent()))
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host, port, err := net.SplitHostPort(r.URL.Host)
if err != nil {
span.SetAttributes(attribute.String("network.peer.address", host))
span.SetAttributes(semconv.ServerAddress(r.URL.Host))
switch r.URL.Scheme {
case "http":
span.SetAttributes(attribute.String("network.peer.port", "80"))
span.SetAttributes(semconv.ServerPort(80))
case "https":
span.SetAttributes(attribute.String("network.peer.port", "443"))
span.SetAttributes(semconv.ServerPort(443))
}
} else {
span.SetAttributes(attribute.String("network.peer.address", host))
span.SetAttributes(attribute.String("network.peer.port", port))
intPort, _ := strconv.Atoi(port)
span.SetAttributes(semconv.ServerAddress(host))
span.SetAttributes(semconv.ServerPort(intPort))
}
for _, header := range t.capturedRequestHeaders {
// User-agent is already part of the semantic convention as a recommended attribute.
if strings.EqualFold(header, "User-Agent") {
continue
}
if value := r.Header[header]; value != nil {
span.SetAttributes(attribute.StringSlice(fmt.Sprintf("http.request.header.%s", strings.ToLower(header)), value))
}
}
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}
// CaptureServerRequest used to add span attributes from the request as a Server.
// TODO: need to update the semconv package as it does not implement fully Semantic Convention v1.23.0.
func (t *Tracer) CaptureServerRequest(span trace.Span, r *http.Request) {
if t == nil || span == nil || r == nil {
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return
}
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// Common attributes https://github.com/open-telemetry/semantic-conventions/blob/v1.23.0/docs/http/http-spans.md#common-attributes
span.SetAttributes(semconv.HTTPRequestMethodKey.String(r.Method))
span.SetAttributes(semconv.NetworkProtocolVersion(proto(r.Proto)))
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// Server attributes https://github.com/open-telemetry/semantic-conventions/blob/v1.23.0/docs/http/http-spans.md#http-server-semantic-conventions
span.SetAttributes(semconv.HTTPRequestBodySize(int(r.ContentLength)))
span.SetAttributes(semconv.URLPath(r.URL.Path))
span.SetAttributes(semconv.URLQuery(r.URL.RawQuery))
span.SetAttributes(semconv.URLScheme(r.Header.Get("X-Forwarded-Proto")))
span.SetAttributes(semconv.UserAgentOriginal(r.UserAgent()))
span.SetAttributes(semconv.ServerAddress(r.Host))
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host, port, err := net.SplitHostPort(r.RemoteAddr)
if err != nil {
span.SetAttributes(semconv.ClientAddress(r.RemoteAddr))
span.SetAttributes(attribute.String("network.peer.address", r.RemoteAddr))
} else {
span.SetAttributes(attribute.String("network.peer.address", host))
span.SetAttributes(attribute.String("network.peer.port", port))
span.SetAttributes(semconv.ClientAddress(host))
intPort, _ := strconv.Atoi(port)
span.SetAttributes(semconv.ClientPort(intPort))
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}
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span.SetAttributes(semconv.ClientSocketAddress(r.Header.Get("X-Forwarded-For")))
for _, header := range t.capturedRequestHeaders {
// User-agent is already part of the semantic convention as a recommended attribute.
if strings.EqualFold(header, "User-Agent") {
continue
}
if value := r.Header[header]; value != nil {
span.SetAttributes(attribute.StringSlice(fmt.Sprintf("http.request.header.%s", strings.ToLower(header)), value))
}
}
}
// CaptureResponse captures the response attributes to the span.
func (t *Tracer) CaptureResponse(span trace.Span, responseHeaders http.Header, code int, spanKind trace.SpanKind) {
if t == nil || span == nil {
return
}
var status codes.Code
var desc string
switch spanKind {
case trace.SpanKindServer:
status, desc = serverStatus(code)
case trace.SpanKindClient:
status, desc = clientStatus(code)
default:
status, desc = defaultStatus(code)
}
span.SetStatus(status, desc)
if code > 0 {
span.SetAttributes(semconv.HTTPResponseStatusCode(code))
}
for _, header := range t.capturedResponseHeaders {
if value := responseHeaders[header]; value != nil {
span.SetAttributes(attribute.StringSlice(fmt.Sprintf("http.response.header.%s", strings.ToLower(header)), value))
}
}
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}
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func proto(proto string) string {
switch proto {
case "HTTP/1.0":
return "1.0"
case "HTTP/1.1":
return "1.1"
case "HTTP/2":
return "2"
case "HTTP/3":
return "3"
default:
return proto
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}
}
// serverStatus returns a span status code and message for an HTTP status code
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// value returned by a server. Status codes in the 400-499 range are not
// returned as errors.
func serverStatus(code int) (codes.Code, string) {
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if code < 100 || code >= 600 {
return codes.Error, fmt.Sprintf("Invalid HTTP status code %d", code)
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}
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if code >= 500 {
return codes.Error, ""
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}
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return codes.Unset, ""
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}
// clientStatus returns a span status code and message for an HTTP status code
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// value returned by a server. Status codes in the 400-499 range are not
// returned as errors.
func clientStatus(code int) (codes.Code, string) {
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if code < 100 || code >= 600 {
return codes.Error, fmt.Sprintf("Invalid HTTP status code %d", code)
}
if code >= 400 {
return codes.Error, ""
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}
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return codes.Unset, ""
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}
// defaultStatus returns a span status code and message for an HTTP status code
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// value generated internally.
func defaultStatus(code int) (codes.Code, string) {
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if code < 100 || code >= 600 {
return codes.Error, fmt.Sprintf("Invalid HTTP status code %d", code)
}
if code >= 500 {
return codes.Error, ""
}
return codes.Unset, ""
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}