From b67da63a4e09c2038563903d9bcf95f691e4fc32 Mon Sep 17 00:00:00 2001
From: Tharun <rajendrantharun@live.com>
Date: Sun, 22 Nov 2020 12:13:58 +0530
Subject: [PATCH] Added profiling for controller

Signed-off-by: Tharun <rajendrantharun@live.com>
---
 cmd/controller/app/controller.go      |  2 +-
 cmd/controller/app/options/options.go |  6 ++++++
 pkg/metrics/metrics.go                | 10 +++++++++-
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/cmd/controller/app/controller.go b/cmd/controller/app/controller.go
index 96a6d76d1..6c9ba900e 100644
--- a/cmd/controller/app/controller.go
+++ b/cmd/controller/app/controller.go
@@ -69,7 +69,7 @@ func Run(opts *options.ControllerOptions, stopCh <-chan struct{}) {
 		os.Exit(1)
 	}
 
-	metricsServer, err := ctx.Metrics.Start(opts.MetricsListenAddress)
+	metricsServer, err := ctx.Metrics.Start(opts.MetricsListenAddress, opts.EnablePprof)
 	if err != nil {
 		log.Error(err, "failed to listen on prometheus address", "address", opts.MetricsListenAddress)
 		os.Exit(1)
diff --git a/cmd/controller/app/options/options.go b/cmd/controller/app/options/options.go
index a4f6a7b66..3b6ddee14 100644
--- a/cmd/controller/app/options/options.go
+++ b/cmd/controller/app/options/options.go
@@ -90,6 +90,9 @@ type ControllerOptions struct {
 	// The host and port address, separated by a ':', that the Prometheus server
 	// should expose metrics on.
 	MetricsListenAddress string
+	// EnablePprof controls whether net/http/pprof handlers are registered with
+	// the HTTP listener.
+	EnablePprof bool
 
 	DNS01CheckRetryPeriod time.Duration
 }
@@ -182,6 +185,7 @@ func NewControllerOptions() *ControllerOptions {
 		EnableCertificateOwnerRef:         defaultEnableCertificateOwnerRef,
 		MetricsListenAddress:              defaultPrometheusMetricsServerAddress,
 		DNS01CheckRetryPeriod:             defaultDNS01CheckRetryPeriod,
+		EnablePprof:                       false,
 	}
 }
 
@@ -285,6 +289,8 @@ func (s *ControllerOptions) AddFlags(fs *pflag.FlagSet) {
 
 	fs.StringVar(&s.MetricsListenAddress, "metrics-listen-address", defaultPrometheusMetricsServerAddress, ""+
 		"The host and port that the metrics endpoint should listen on.")
+	fs.BoolVar(&s.EnablePprof, "enable-profiling", false, ""+
+		"Enable profiling for controller.")
 }
 
 func (o *ControllerOptions) Validate() error {
diff --git a/pkg/metrics/metrics.go b/pkg/metrics/metrics.go
index 173e93d52..2f28ce511 100644
--- a/pkg/metrics/metrics.go
+++ b/pkg/metrics/metrics.go
@@ -27,6 +27,7 @@ import (
 	"context"
 	"net"
 	"net/http"
+	pprof "net/http/pprof"
 	"time"
 
 	logf "github.com/jetstack/cert-manager/pkg/logs"
@@ -134,7 +135,7 @@ func New(log logr.Logger) *Metrics {
 }
 
 // Start will register the Prometheu metrics, and start the Prometheus server
-func (m *Metrics) Start(listenAddress string) (*http.Server, error) {
+func (m *Metrics) Start(listenAddress string, enablePprof bool) (*http.Server, error) {
 	m.registry.MustRegister(m.certificateExpiryTimeSeconds)
 	m.registry.MustRegister(m.certificateReadyStatus)
 	m.registry.MustRegister(m.acmeClientRequestDurationSeconds)
@@ -143,6 +144,13 @@ func (m *Metrics) Start(listenAddress string) (*http.Server, error) {
 
 	router := mux.NewRouter()
 	router.Handle("/metrics", promhttp.HandlerFor(m.registry, promhttp.HandlerOpts{}))
+	if enablePprof {
+		router.HandleFunc("/debug/pprof/", pprof.Index)
+		router.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
+		router.HandleFunc("/debug/pprof/profile", pprof.Profile)
+		router.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
+		router.HandleFunc("/debug/pprof/trace", pprof.Trace)
+	}
 
 	ln, err := net.Listen("tcp", listenAddress)
 	if err != nil {