add go pprof capabilities

app/node/prof.go

@@ -0,0 +1,93 @@
+package node
+
+import (
+	"fmt"
+	"net/http"
+	_ "net/http/pprof"
+	"os"
+	"runtime"
+	"runtime/pprof"
+	"time"
+)
+
+type profMode string
+
+const (
+	profModeDisabled profMode = ""
+	profModeHTTP     profMode = "http"
+	profModeCPU      profMode = "cpu"
+	profModeMem      profMode = "mem"
+	profModeBlock    profMode = "block"
+	profModeMutex    profMode = "mutex"
+)
+
+func startProfilers(mode profMode, pprofFile string) (func(), error) {
+	if pprofFile == "" {
+		pprofFile = fmt.Sprintf("kwild-%s.pprof", mode)
+	}
+
+	switch mode {
+	case profModeHTTP:
+		// http pprof uses http.DefaultServeMux, so we register a redirect
+		// handler with the root path on the default mux.
+		http.Handle("/", http.RedirectHandler("/debug/pprof/", http.StatusSeeOther))
+		go func() {
+			if err := http.ListenAndServe("localhost:6060", nil); err != nil {
+				fmt.Printf("http.ListenAndServe: %v\n", err)
+			}
+		}()
+		return func() {}, nil
+	case profModeCPU:
+		f, err := os.Create(pprofFile)
+		if err != nil {
+			return nil, err
+		}
+		err = pprof.StartCPUProfile(f)
+		if err != nil {
+			return nil, fmt.Errorf("error starting CPU profiler: %w", err)
+		}
+		return pprof.StopCPUProfile, nil
+	case profModeMem:
+		f, err := os.Create(pprofFile)
+		if err != nil {
+			return nil, err
+		}
+		timer := time.NewTimer(time.Second * 15)
+		go func() {
+			<-timer.C
+			if err = pprof.WriteHeapProfile(f); err != nil {
+				fmt.Printf("WriteHeapProfile: %v\n", err)
+			}
+			f.Close()
+		}()
+		return func() { timer.Reset(0) }, nil
+	case profModeBlock:
+		f, err := os.Create(pprofFile)
+		if err != nil {
+			return nil, fmt.Errorf("could not create block profile file %q: %v", pprofFile, err)
+		}
+		runtime.SetBlockProfileRate(1)
+		return func() {
+			pprof.Lookup("block").WriteTo(f, 0)
+			f.Close()
+			runtime.SetBlockProfileRate(0)
+		}, nil
+	case profModeMutex:
+		f, err := os.Create(pprofFile)
+		if err != nil {
+			return nil, fmt.Errorf("could not create mutex profile file %q: %v", pprofFile, err)
+		}
+		runtime.SetMutexProfileFraction(1)
+		return func() {
+			if mp := pprof.Lookup("mutex"); mp != nil {
+				mp.WriteTo(f, 0)
+			}
+			f.Close()
+			runtime.SetMutexProfileFraction(0)
+		}, nil
+	case profModeDisabled:
+		return func() {}, nil
+	default:
+		return nil, fmt.Errorf("unknown profile mode %s", mode)
+	}
+}

app/node/start.go

@@ -40,6 +40,13 @@ func StartCmd() *cobra.Command {
 				return string(rawToml)
 			}))
 
+			stopProfiler, err := startProfilers(profMode(cfg.ProfileMode), cfg.ProfileFile)
+			if err != nil {
+				cmd.Usage()
+				return err
+			}
+			defer stopProfiler()
+
 			return runNode(cmd.Context(), rootDir, cfg)
 		},
 	}

config/config.go

@@ -208,8 +208,8 @@ type Config struct {
 	LogFormat log.Format `toml:"log_format" comment:"log format\npossible values: 'json', 'text' (kv), and 'plain' (fmt-style)"`
 	// LogOutput []string   `toml:"log_output" comment:"output paths for the log"`
 
-	// ProfileMode string `toml:"profile_mode"`
-	// ProfileFile string `toml:"profile_file"`
+	ProfileMode string `toml:"profile_mode,commented" comment:"profile mode (http, cpu, mem, mutex, or block)"`
+	ProfileFile string `toml:"profile_file,commented" comment:"profile output file path (e.g. cpu.pprof)"`
 
 	P2P          PeerConfig                   `toml:"p2p" comment:"P2P related configuration"`
 	Consensus    ConsensusConfig              `toml:"consensus" comment:"Consensus related configuration"`