Allow pprof profiling HTTP API (#132)

* Allow pprof profiling HTTP endpoints

Author: timvaillancourt

cmd/freno/main.go

@@ -44,6 +44,7 @@ func main() {
 	verbose := flag.Bool("verbose", false, "verbose")
 	debug := flag.Bool("debug", false, "debug mode (very verbose)")
 	stack := flag.Bool("stack", false, "add stack trace upon error")
+	enableProfiling := flag.Bool("enable-profiling", false, "enable pprof profiling http api")
 
 	help := flag.Bool("help", false, "show the help")
 	flag.Parse()
@@ -89,6 +90,9 @@ func main() {
 	if *httpPort > 0 {
 		config.Settings().ListenPort = *httpPort
 	}
+	if *enableProfiling {
+		config.Settings().EnableProfiling = *enableProfiling
+	}
 
 	switch {
 	case *http:

pkg/config/config.go

@@ -108,6 +108,7 @@ type ConfigurationSettings struct {
 	BackendMySQLPassword string
 	MemcacheServers      []string // if given, freno will report to aggregated values to given memcache
 	MemcachePath         string   // use as prefix to metric path in memcache key, e.g. if `MemcachePath` is "myprefix" the key would be "myprefix/mysql/maincluster". Default: "freno"
+	EnableProfiling      bool     // enable pprof profiling http api
 	Stores               StoresSettings
 }
 

pkg/http/api.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"net/http/pprof"
 	"os"
 	"strconv"
 	"strings"
@@ -370,6 +371,18 @@ func ConfigureRoutes(api API) *httprouter.Router {
 	register(router, "/debug/vars", metricsHandle)
 	register(router, "/debug/metrics", metricsHandle)
 
+	if config.Settings().EnableProfiling {
+		router.HandlerFunc(http.MethodGet, "/debug/pprof/", pprof.Index)
+		router.HandlerFunc(http.MethodGet, "/debug/pprof/cmdline", pprof.Cmdline)
+		router.HandlerFunc(http.MethodGet, "/debug/pprof/profile", pprof.Profile)
+		router.HandlerFunc(http.MethodGet, "/debug/pprof/symbol", pprof.Symbol)
+		router.HandlerFunc(http.MethodGet, "/debug/pprof/trace", pprof.Trace)
+		router.Handler(http.MethodGet, "/debug/pprof/goroutine", pprof.Handler("goroutine"))
+		router.Handler(http.MethodGet, "/debug/pprof/heap", pprof.Handler("heap"))
+		router.Handler(http.MethodGet, "/debug/pprof/threadcreate", pprof.Handler("threadcreate"))
+		router.Handler(http.MethodGet, "/debug/pprof/block", pprof.Handler("block"))
+	}
+
 	register(router, "/help", api.Help)
 
 	router.GET("/config/memcache", api.MemcacheConfig)