From 0bef57a6002e2fcd0e878358e5152a66a2216be2 Mon Sep 17 00:00:00 2001
From: Sergey Lanzman <sergeylanz@google.com>
Date: Fri, 24 Aug 2018 20:51:56 +0300
Subject: [PATCH] add SetUntraceableEndpoints for add UntraceableEndpoints like
 Health urls

---
 plugin/ochttp/client.go |  2 +-
 plugin/ochttp/server.go |  2 +-
 plugin/ochttp/trace.go  | 26 +++++++++++++++++++-------
 3 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/plugin/ochttp/client.go b/plugin/ochttp/client.go
index 68faf24f5..38d451575 100644
--- a/plugin/ochttp/client.go
+++ b/plugin/ochttp/client.go
@@ -63,7 +63,7 @@ type Transport struct {
 // RoundTrip implements http.RoundTripper, delegating to Base and recording stats and traces for the request.
 func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
 	rt := t.base()
-	if isHealthEndpoint(req.URL.Path) {
+	if isUntraceableEndpoints(req.URL.Path) {
 		return rt.RoundTrip(req)
 	}
 	// TODO: remove excessive nesting of http.RoundTrippers here.
diff --git a/plugin/ochttp/server.go b/plugin/ochttp/server.go
index 72aa8c2d7..c6b9da51e 100644
--- a/plugin/ochttp/server.go
+++ b/plugin/ochttp/server.go
@@ -82,7 +82,7 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *Handler) startTrace(w http.ResponseWriter, r *http.Request) (*http.Request, func()) {
-	if isHealthEndpoint(r.URL.Path) {
+	if isUntraceableEndpoints(r.URL.Path) {
 		return r, func() {}
 	}
 	var name string
diff --git a/plugin/ochttp/trace.go b/plugin/ochttp/trace.go
index 980b6390f..351a11cb7 100644
--- a/plugin/ochttp/trace.go
+++ b/plugin/ochttp/trace.go
@@ -28,6 +28,13 @@ import (
 
 var defaultFormat propagation.HTTPFormat = &b3.HTTPFormat{}
 
+// Disable canonical health checking endpoints
+// like /healthz and /_ah/health for now.
+var untraceableEndpoints = map[string]bool{
+	"/healthz":    true,
+	"/_ah/health": true,
+}
+
 // Attributes recorded on the span for the requests.
 // Only trace exporters will need them.
 const (
@@ -205,13 +212,18 @@ var codeToStr = map[int32]string{
 	trace.StatusCodeUnauthenticated:    `"UNAUTHENTICATED"`,
 }
 
-func isHealthEndpoint(path string) bool {
-	// Health checking is pretty frequent and
-	// traces collected for health endpoints
-	// can be extremely noisy and expensive.
-	// Disable canonical health checking endpoints
-	// like /healthz and /_ah/health for now.
-	if path == "/healthz" || path == "/_ah/health" {
+// Set Untraceable Endpoints like Health checking
+// is pretty frequent and traces collected
+// for health endpoints can be extremely noisy and expensive.
+func SetUntraceableEndpoints(newUntraceableEndpoints []string) {
+	untraceableEndpoints = map[string]bool{}
+	for _, endpoint := range newUntraceableEndpoints {
+		untraceableEndpoints[endpoint] = true
+	}
+}
+
+func isUntraceableEndpoints(path string) bool {
+	if _, exist := untraceableEndpoints[path]; exist {
 		return true
 	}
 	return false