Opentracing support

middlewares/tracing/forwarder.go

@@ -0,0 +1,46 @@
+package tracing
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/containous/traefik/log"
+	"github.com/opentracing/opentracing-go/ext"
+	"github.com/urfave/negroni"
+)
+
+type forwarderMiddleware struct {
+	frontend string
+	backend  string
+	opName   string
+	*Tracing
+}
+
+// NewForwarderMiddleware creates a new forwarder middleware that traces the outgoing request
+func (t *Tracing) NewForwarderMiddleware(frontend, backend string) negroni.Handler {
+	log.Debugf("Added outgoing tracing middleware %s", frontend)
+	return &forwarderMiddleware{
+		Tracing:  t,
+		frontend: frontend,
+		backend:  backend,
+		opName:   fmt.Sprintf("forward %s/%s", frontend, backend),
+	}
+}
+
+func (f *forwarderMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
+	span, r, finish := StartSpan(r, f.opName, true)
+	defer finish()
+	span.SetTag("frontend.name", f.frontend)
+	span.SetTag("backend.name", f.backend)
+	ext.HTTPMethod.Set(span, r.Method)
+	ext.HTTPUrl.Set(span, r.URL.String())
+	span.SetTag("http.host", r.Host)
+
+	InjectRequestHeaders(r)
+
+	w = &statusCodeTracker{w, 200}
+
+	next(w, r)
+
+	LogResponseCode(span, w.(*statusCodeTracker).status)
+}