72 lines
1.9 KiB
Go
72 lines
1.9 KiB
Go
package observability
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import (
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"context"
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"net/http"
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"github.com/containous/alice"
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"github.com/rs/zerolog/log"
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"github.com/traefik/traefik/v3/pkg/logs"
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"github.com/traefik/traefik/v3/pkg/tracing"
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"go.opentelemetry.io/otel/attribute"
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"go.opentelemetry.io/otel/trace"
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)
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// Traceable embeds tracing information.
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type Traceable interface {
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GetTracingInformation() (name string, typeName string, spanKind trace.SpanKind)
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}
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// WrapMiddleware adds traceability to an alice.Constructor.
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func WrapMiddleware(ctx context.Context, constructor alice.Constructor) alice.Constructor {
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return func(next http.Handler) (http.Handler, error) {
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if constructor == nil {
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return nil, nil
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}
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handler, err := constructor(next)
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if err != nil {
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return nil, err
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}
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if traceableHandler, ok := handler.(Traceable); ok {
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name, typeName, spanKind := traceableHandler.GetTracingInformation()
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log.Ctx(ctx).Debug().Str(logs.MiddlewareName, name).Msg("Adding tracing to middleware")
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return NewMiddleware(handler, name, typeName, spanKind), nil
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}
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return handler, nil
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}
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}
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// NewMiddleware returns a http.Handler struct.
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func NewMiddleware(next http.Handler, name string, typeName string, spanKind trace.SpanKind) http.Handler {
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return &middlewareTracing{
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next: next,
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name: name,
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typeName: typeName,
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spanKind: spanKind,
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}
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}
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// middlewareTracing is used to wrap http handler middleware.
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type middlewareTracing struct {
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next http.Handler
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name string
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typeName string
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spanKind trace.SpanKind
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}
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func (w *middlewareTracing) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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if tracer := tracing.TracerFromContext(req.Context()); tracer != nil {
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tracingCtx, span := tracer.Start(req.Context(), w.typeName, trace.WithSpanKind(w.spanKind))
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defer span.End()
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req = req.WithContext(tracingCtx)
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span.SetAttributes(attribute.String("traefik.middleware.name", w.name))
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}
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if w.next != nil {
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w.next.ServeHTTP(rw, req)
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}
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}
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