Add helper for setting up pprof handlers

This follows the suggestion of controller-runtime to use the metrics
server for registering the handlers using `AddMetricsExtraHandler`.

Signed-off-by: Hidde Beydals <hello@hidde.co>

runtime/pprof/pprof.go

@@ -0,0 +1,41 @@
+/*
+Copyright 2021 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package pprof
+
+import (
+	"net/http"
+	"net/http/pprof"
+
+	"github.com/go-logr/logr"
+	ctrl "sigs.k8s.io/controller-runtime"
+)
+
+var endpoints = map[string]http.Handler{
+	"/debug/pprof/":        http.HandlerFunc(pprof.Index),
+	"/debug/pprof/cmdline": http.HandlerFunc(pprof.Cmdline),
+	"/debug/pprof/profile": http.HandlerFunc(pprof.Profile),
+	"/debug/pprof/symbol":  http.HandlerFunc(pprof.Symbol),
+	"/debug/pprof/trace":   http.HandlerFunc(pprof.Trace),
+}
+
+func SetupHandlers(mgr ctrl.Manager, setupLog logr.Logger) {
+	for p, h := range endpoints {
+		if err := mgr.AddMetricsExtraHandler(p, h); err != nil {
+			setupLog.Error(err, "unable to add pprof handler")
+		}
+	}
+}