Dynamic Configuration Refactoring

old/middlewares/tracing/entrypoint.go

@@ -0,0 +1,57 @@
+package tracing
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/containous/traefik/old/log"
+	"github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/ext"
+	"github.com/urfave/negroni"
+)
+
+type entryPointMiddleware struct {
+	entryPoint string
+	*Tracing
+}
+
+// NewEntryPoint creates a new middleware that the incoming request
+func (t *Tracing) NewEntryPoint(name string) negroni.Handler {
+	log.Debug("Added entrypoint tracing middleware")
+	return &entryPointMiddleware{Tracing: t, entryPoint: name}
+}
+
+func (e *entryPointMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
+	opNameFunc := generateEntryPointSpanName
+
+	ctx, _ := e.Extract(opentracing.HTTPHeaders, HTTPHeadersCarrier(r.Header))
+	span := e.StartSpan(opNameFunc(r, e.entryPoint, e.SpanNameLimit), ext.RPCServerOption(ctx))
+	ext.Component.Set(span, e.ServiceName)
+	LogRequest(span, r)
+	ext.SpanKindRPCServer.Set(span)
+
+	r = r.WithContext(opentracing.ContextWithSpan(r.Context(), span))
+
+	recorder := newStatusCodeRecoder(w, 200)
+	next(recorder, r)
+
+	LogResponseCode(span, recorder.Status())
+	span.Finish()
+}
+
+// generateEntryPointSpanName will return a Span name of an appropriate lenth based on the 'spanLimit' argument.  If needed, it will be truncated, but will not be less than 24 characters.
+func generateEntryPointSpanName(r *http.Request, entryPoint string, spanLimit int) string {
+	name := fmt.Sprintf("Entrypoint %s %s", entryPoint, r.Host)
+
+	if spanLimit > 0 && len(name) > spanLimit {
+		if spanLimit < EntryPointMaxLengthNumber {
+			log.Warnf("SpanNameLimit is set to be less than required static number of characters, defaulting to %d + 3", EntryPointMaxLengthNumber)
+			spanLimit = EntryPointMaxLengthNumber + 3
+		}
+		hash := computeHash(name)
+		limit := (spanLimit - EntryPointMaxLengthNumber) / 2
+		name = fmt.Sprintf("Entrypoint %s %s %s", truncateString(entryPoint, limit), truncateString(r.Host, limit), hash)
+	}
+
+	return name
+}