From bbc9671d50eed2223a05bb2af204ac2dacbf38e2 Mon Sep 17 00:00:00 2001
From: Tom Wilkie <tom.wilkie@gmail.com>
Date: Fri, 1 Sep 2017 12:12:51 +0100
Subject: [PATCH] Get profile handlers working again after #3054 and #3146.

Ensures the pprod endpoints deal with path-prefixes correctly; adds a test so we don't break it again.
---
 web/web.go      |  6 ++++++
 web/web_test.go | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/web/web.go b/web/web.go
index 1c6d7fb95..0f87f6b94 100644
--- a/web/web.go
+++ b/web/web.go
@@ -246,6 +246,11 @@ func serveDebug(w http.ResponseWriter, req *http.Request) {
 	ctx := req.Context()
 	subpath := route.Param(ctx, "subpath")
 
+	if subpath == "/pprof" {
+		http.Redirect(w, req, req.URL.Path+"/", http.StatusMovedPermanently)
+		return
+	}
+
 	if !strings.HasPrefix(subpath, "/pprof/") {
 		http.NotFound(w, req)
 		return
@@ -262,6 +267,7 @@ func serveDebug(w http.ResponseWriter, req *http.Request) {
 	case "trace":
 		pprof.Trace(w, req)
 	default:
+		req.URL.Path = "/debug/pprof/" + subpath
 		pprof.Index(w, req)
 	}
 }
diff --git a/web/web_test.go b/web/web_test.go
index 9784a17b9..ef54ac04a 100644
--- a/web/web_test.go
+++ b/web/web_test.go
@@ -15,6 +15,7 @@ package web
 
 import (
 	"net/http"
+	"net/http/httptest"
 	"net/url"
 	"testing"
 	"time"
@@ -146,3 +147,37 @@ func TestReadyAndHealthy(t *testing.T) {
 	}
 
 }
+
+func TestDebugHandler(t *testing.T) {
+	for _, tc := range []struct {
+		prefix, url string
+		code        int
+	}{
+		{"/", "/debug/pprof/cmdline", 200},
+		{"/foo", "/foo/debug/pprof/cmdline", 200},
+
+		{"/", "/debug/pprof/goroutine", 200},
+		{"/foo", "/foo/debug/pprof/goroutine", 200},
+
+		{"/", "/debug/pprof/foo", 404},
+		{"/foo", "/bar/debug/pprof/goroutine", 404},
+	} {
+		opts := &Options{
+			RoutePrefix: tc.prefix,
+			MetricsPath: "/metrics",
+		}
+		handler := New(opts)
+		handler.Ready()
+
+		w := httptest.NewRecorder()
+		req, err := http.NewRequest("GET", tc.url, nil)
+		if err != nil {
+			t.Fatalf("Unexpected error %s", err)
+		}
+
+		handler.router.ServeHTTP(w, req)
+		if w.Code != tc.code {
+			t.Fatalf("Unexpected status code %d: %s", w.Code, w.Body.String())
+		}
+	}
+}