bunrouterotel/add http.forward_route;

bunrouterotel/middleware.go

@@ -2,6 +2,7 @@ package bunrouterotel
 
 import (
 	"net/http"
+	"strings"
 
 	"github.com/uptrace/bunrouter"
 	"go.opentelemetry.io/otel"
@@ -13,9 +14,11 @@ import (
 
 const (
 	tracerName = "git.blauwelle.com/go/crate/bunrouterotel"
-	version    = "0.2.0"
+	version    = "0.4.0"
 )
 
+var tracer = otel.Tracer(tracerName, trace.WithInstrumentationVersion("semver:"+version))
+
 type config struct {
 	propagators propagation.TextMapPropagator
 }
@@ -36,6 +39,15 @@ func WithPropagators(propagators propagation.TextMapPropagator) Option {
 	})
 }
 
+func getForwardedFor(r *http.Request) []string {
+	h := r.Header.Get("X-Forwarded-For")
+	a := strings.Split(h, ",")
+	for i, s := range a {
+		a[i] = strings.Trim(s, " \t")
+	}
+	return a
+}
+
 // Middleware create a span, which record the request,
 // HTTP status code is NOT recorded.
 func Middleware(serverName string, opts ...Option) bunrouter.MiddlewareFunc {
@@ -46,7 +58,6 @@ func Middleware(serverName string, opts ...Option) bunrouter.MiddlewareFunc {
 	if cfg.propagators == nil {
 		cfg.propagators = otel.GetTextMapPropagator()
 	}
-	tracer := otel.Tracer(tracerName, trace.WithInstrumentationVersion("semver:"+version))
 	return func(next bunrouter.HandlerFunc) bunrouter.HandlerFunc {
 		return func(w http.ResponseWriter, req bunrouter.Request) error {
 			ctx := cfg.propagators.Extract(req.Context(), propagation.HeaderCarrier(req.Header))
@@ -75,6 +86,10 @@ func Middleware(serverName string, opts ...Option) bunrouter.MiddlewareFunc {
 				attrs = append(attrs, attribute.String("http.route.param."+param.Key, param.Value))
 			}
 			span.SetAttributes(attrs...)
+			forwardedFor := getForwardedFor(req.Request)
+			if forwardedFor != nil {
+				span.SetAttributes(attribute.StringSlice("http.forward_route", forwardedFor))
+			}
 			defer span.End()
 			return next(w, req)
 		}