chore: remove GUI "debugging" toggle, debug HTTP metrics (#10235)

This removes the `debugging` bool under GUI configuration, and two no
longer relevant development endpoints: `httpmetrics` (which I can't
imagine anyone using for anything -- if we need such metrics today, the
right place is the Prometheus exported metrics) and the `peerCompletion`
endpoint (previously used by integration tests).

The debugging bool initially enabled just those two endpoints, which are
not for end users. Then we added profiling and support bundles, which
are very useful indeed for end users to access, and they were hidden
behind the same debug flag. I don't see any reason for keeping that flag
now that these methods are more generally useful.

https://github.com/syncthing/docs/pull/949

gui/default/index.html

@@ -108,7 +108,7 @@
               <li><a href="" ng-click="about.show()"><span class="fa fa-fw fa-heart"></span>&nbsp;<span translate>About</span></a></li>
             </ul>
           </li>
-          <li ng-if="authenticated || config.gui.debugging" class="dropdown action-menu">
+          <li ng-if="authenticated" class="dropdown action-menu">
             <a href="#" class="dropdown-toggle" data-toggle="dropdown" aria-expanded="false">
               <span class="fa fa-cog"></span>
               <span class="hidden-xs" translate>Actions</span>
@@ -116,14 +116,13 @@
             </a>
             <ul class="dropdown-menu">
               <li ng-if="authenticated"><a href="" ng-click="showSettings()"><span class="fa fa-fw fa-cog"></span>&nbsp;<span translate>Settings</span></a></li>
-              <li ng-if="authenticated"><a href="" ng-click="showDeviceIdentification(thisDevice())"><span class="fa fa-fw fa-qrcode"></span>&nbsp;<span translate>Show ID</span></a></li>
+              <li ng-if="authenticated"><a href="" ng-click="advanced()"><span class="fa fa-fw fa-cogs"></span>&nbsp;<span translate>Advanced</span></a></li>
 
               <li ng-if="authenticated" class="divider" aria-hidden="true"></li>
-              <li ng-if="authenticated"><a href="" ng-click="advanced()"><span class="fa fa-fw fa-cogs"></span>&nbsp;<span translate>Advanced</span></a></li>
-              <li ng-if="authenticated"><a href="" ng-click="logging.show()"><span class="fa fa-fw fa-wrench"></span>&nbsp;<span translate>Logs</span></a></li>
 
-              <li class="divider" aria-hidden="true" ng-if="config.gui.debugging"></li>
-              <li><a href="/rest/debug/support" target="_blank" ng-if="config.gui.debugging"><span class="fa fa-fw fa-user-md"></span>&nbsp;<span translate>Support Bundle</span></a></li>
+              <li ng-if="authenticated"><a href="" ng-click="showDeviceIdentification(thisDevice())"><span class="fa fa-fw fa-qrcode"></span>&nbsp;<span translate>Show ID</span></a></li>
+              <li ng-if="authenticated"><a href="" ng-click="logging.show()"><span class="fa fa-fw fa-wrench"></span>&nbsp;<span translate>Logs</span></a></li>
+              <li ng-if="authenticated"><a href="/rest/debug/support" target="_blank"><span class="fa fa-fw fa-user-md"></span>&nbsp;<span translate>Support Bundle</span></a></li>
 
               <li ng-if="authenticated" class="divider" aria-hidden="true"></li>
               <li ng-if="authenticated && isAuthEnabled()"><a href="" ng-click="logout()"><span class="far fa-fw fa-sign-out"></span>&nbsp;<span translate>Log Out</span></a></li>

lib/api/api.go

@@ -36,7 +36,6 @@ import (
 	"github.com/calmh/incontainer"
 	"github.com/julienschmidt/httprouter"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
-	"github.com/rcrowley/go-metrics"
 	"github.com/thejerf/suture/v4"
 	"github.com/vitrun/qart/qr"
 	"golang.org/x/text/runes"
@@ -336,16 +335,14 @@ func (s *service) Serve(ctx context.Context) error {
 
 	// Debug endpoints, not for general use
 	debugMux := http.NewServeMux()
-	debugMux.HandleFunc("/rest/debug/peerCompletion", s.getPeerCompletion)
-	debugMux.HandleFunc("/rest/debug/httpmetrics", s.getSystemHTTPMetrics)
 	debugMux.HandleFunc("/rest/debug/cpuprof", s.getCPUProf) // duration
 	debugMux.HandleFunc("/rest/debug/heapprof", s.getHeapProf)
 	debugMux.HandleFunc("/rest/debug/support", s.getSupportBundle)
 	debugMux.HandleFunc("/rest/debug/file", s.getDebugFile)
-	restMux.Handler(http.MethodGet, "/rest/debug/*method", s.whenDebugging(debugMux))
+	restMux.Handler(http.MethodGet, "/rest/debug/*method", debugMux)
 
 	// A handler that disables caching
-	noCacheRestMux := noCacheMiddleware(metricsMiddleware(restMux))
+	noCacheRestMux := noCacheMiddleware(restMux)
 
 	// The main routing handler
 	mux := http.NewServeMux()
@@ -489,9 +486,6 @@ func (*service) VerifyConfiguration(_, to config.Configuration) error {
 }
 
 func (s *service) CommitConfiguration(from, to config.Configuration) bool {
-	// No action required when this changes, so mask the fact that it changed at all.
-	from.GUI.Debugging = to.GUI.Debugging
-
 	if to.GUI == from.GUI {
 		// No GUI changes, we're done here.
 		return true
@@ -594,15 +588,6 @@ func corsMiddleware(next http.Handler, allowFrameLoading bool) http.Handler {
 	})
 }
 
-func metricsMiddleware(h http.Handler) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		t := metrics.GetOrRegisterTimer(r.URL.Path, nil)
-		t0 := time.Now()
-		h.ServeHTTP(w, r)
-		t.UpdateSince(t0)
-	})
-}
-
 func redirectToHTTPSMiddleware(h http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.TLS == nil {
@@ -644,17 +629,6 @@ func localhostMiddleware(h http.Handler) http.Handler {
 	})
 }
 
-func (s *service) whenDebugging(h http.Handler) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		if s.cfg.GUI().Debugging {
-			h.ServeHTTP(w, r)
-			return
-		}
-
-		http.Error(w, "Debugging disabled", http.StatusForbidden)
-	})
-}
-
 func (s *service) getPendingDevices(w http.ResponseWriter, _ *http.Request) {
 	devices, err := s.model.PendingDevices()
 	if err != nil {
@@ -1284,26 +1258,6 @@ func (s *service) getSupportBundle(w http.ResponseWriter, r *http.Request) {
 	io.Copy(w, &zipFilesBuffer)
 }
 
-func (*service) getSystemHTTPMetrics(w http.ResponseWriter, _ *http.Request) {
-	stats := make(map[string]interface{})
-	metrics.Each(func(name string, intf interface{}) {
-		if m, ok := intf.(*metrics.StandardTimer); ok {
-			pct := m.Percentiles([]float64{0.50, 0.95, 0.99})
-			for i := range pct {
-				pct[i] /= 1e6 // ns to ms
-			}
-			stats[name] = map[string]interface{}{
-				"count":         m.Count(),
-				"sumMs":         m.Sum() / 1e6, // ns to ms
-				"ratesPerS":     []float64{m.Rate1(), m.Rate5(), m.Rate15()},
-				"percentilesMs": pct,
-			}
-		}
-	})
-	bs, _ := json.MarshalIndent(stats, "", "  ")
-	w.Write(bs)
-}
-
 func (s *service) getSystemDiscovery(w http.ResponseWriter, _ *http.Request) {
 	devices := make(map[string]discover.CacheEntry)
 
@@ -1628,35 +1582,6 @@ func (*service) getQR(w http.ResponseWriter, r *http.Request) {
 	w.Write(code.PNG())
 }
 
-func (s *service) getPeerCompletion(w http.ResponseWriter, _ *http.Request) {
-	tot := map[string]float64{}
-	count := map[string]float64{}
-
-	for _, folder := range s.cfg.Folders() {
-		for _, device := range folder.DeviceIDs() {
-			deviceStr := device.String()
-			if s.model.ConnectedTo(device) {
-				comp, err := s.model.Completion(device, folder.ID)
-				if err != nil {
-					http.Error(w, err.Error(), http.StatusInternalServerError)
-					return
-				}
-				tot[deviceStr] += comp.CompletionPct
-			} else {
-				tot[deviceStr] = 0
-			}
-			count[deviceStr]++
-		}
-	}
-
-	comp := map[string]int{}
-	for device := range tot {
-		comp[device] = int(tot[device] / count[device])
-	}
-
-	sendJSON(w, comp)
-}
-
 func (s *service) getFolderVersions(w http.ResponseWriter, r *http.Request) {
 	qs := r.URL.Query()
 	versions, err := s.model.GetFolderVersions(qs.Get("folder"))

lib/config/guiconfiguration.go

@@ -30,7 +30,6 @@ type GUIConfiguration struct {
 	APIKey                    string   `json:"apiKey" xml:"apikey,omitempty"`
 	InsecureAdminAccess       bool     `json:"insecureAdminAccess" xml:"insecureAdminAccess,omitempty"`
 	Theme                     string   `json:"theme" xml:"theme" default:"default"`
-	Debugging                 bool     `json:"debugging" xml:"debugging,attr"`
 	InsecureSkipHostCheck     bool     `json:"insecureSkipHostcheck" xml:"insecureSkipHostcheck,omitempty"`
 	InsecureAllowFrameLoading bool     `json:"insecureAllowFrameLoading" xml:"insecureAllowFrameLoading,omitempty"`
 	SendBasicAuthPrompt       bool     `json:"sendBasicAuthPrompt" xml:"sendBasicAuthPrompt,attr"`

lib/ur/usage_report.go

@@ -308,9 +308,6 @@ func (s *Service) reportData(ctx context.Context, urVersion int, preview bool) (
 			if guiCfg.InsecureAdminAccess {
 				report.GUIStats.InsecureAdminAccess++
 			}
-			if guiCfg.Debugging {
-				report.GUIStats.Debugging++
-			}
 			if guiCfg.InsecureSkipHostCheck {
 				report.GUIStats.InsecureSkipHostCheck++
 			}

test/h1/config.xml

@@ -65,7 +65,7 @@
         <remoteGUIPort>0</remoteGUIPort>
         <numConnections>3</numConnections>
     </device>
-    <gui enabled="true" tls="false" debugging="true" sendBasicAuthPrompt="false">
+    <gui enabled="true" tls="false" sendBasicAuthPrompt="false">
         <address>127.0.0.1:8081</address>
         <user>testuser</user>
         <password>$2a$10$7tKL5uvLDGn5s2VLPM2yWOK/II45az0mTel8hxAUJDRQN1Tk2QYwu</password>

test/h2/config.xml

@@ -65,7 +65,7 @@
         <remoteGUIPort>0</remoteGUIPort>
         <numConnections>3</numConnections>
     </device>
-    <gui enabled="true" tls="false" debugging="true" sendBasicAuthPrompt="false">
+    <gui enabled="true" tls="false" sendBasicAuthPrompt="false">
         <address>127.0.0.1:8082</address>
         <metricsWithoutAuth>false</metricsWithoutAuth>
         <apikey>abc123</apikey>