debug/api.go
// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// Package debug interfaces Go runtime debugging facilities.
// This package is mostly glue code making these facilities available
// through the CLI and RPC subsystem. If you want to use them from Go code,
// use package runtime instead.
package debug
import (
"bytes"
"errors"
"io"
"os"
"os/user"
"path/filepath"
"runtime"
"runtime/debug"
"runtime/pprof"
"strings"
"sync"
"time"
"github.com/ethereum/go-ethereum/log"
)
// Handler is the global debugging handler.
var Handler = new(HandlerT)
// HandlerT implements the debugging API.
// Do not create values of this type, use the one
// in the Handler variable instead.
type HandlerT struct {
mu sync.Mutex
cpuW io.WriteCloser
cpuFile string
traceW io.WriteCloser
traceFile string
}
// Verbosity sets the log verbosity ceiling. The verbosity of individual packages
// and source files can be raised using Vmodule.
func (*HandlerT) Verbosity(level int) {
glogger.Verbosity(log.Lvl(level))
}
// Vmodule sets the log verbosity pattern. See package log for details on the
// pattern syntax.
func (*HandlerT) Vmodule(pattern string) error {
return glogger.Vmodule(pattern)
}
// BacktraceAt sets the log backtrace location. See package log for details on
// the pattern syntax.
func (*HandlerT) BacktraceAt(location string) error {
return glogger.BacktraceAt(location)
}
// MemStats returns detailed runtime memory statistics.
func (*HandlerT) MemStats() *runtime.MemStats {
s := new(runtime.MemStats)
runtime.ReadMemStats(s)
return s
}
// GcStats returns GC statistics.
func (*HandlerT) GcStats() *debug.GCStats {
s := new(debug.GCStats)
debug.ReadGCStats(s)
return s
}
// CpuProfile turns on CPU profiling for nsec seconds and writes
// profile data to file.
func (h *HandlerT) CpuProfile(file string, nsec uint) error {
if err := h.StartCPUProfile(file); err != nil {
return err
}
time.Sleep(time.Duration(nsec) * time.Second)
h.StopCPUProfile()
return nil
}
// StartCPUProfile turns on CPU profiling, writing to the given file.
func (h *HandlerT) StartCPUProfile(file string) error {
h.mu.Lock()
defer h.mu.Unlock()
if h.cpuW != nil {
return errors.New("CPU profiling already in progress")
}
f, err := os.Create(expandHome(file))
if err != nil {
return err
}
if err := pprof.StartCPUProfile(f); err != nil {
f.Close()
return err
}
h.cpuW = f
h.cpuFile = file
log.Info("CPU profiling started", "dump", h.cpuFile)
return nil
}
// StopCPUProfile stops an ongoing CPU profile.
func (h *HandlerT) StopCPUProfile() error {
h.mu.Lock()
defer h.mu.Unlock()
pprof.StopCPUProfile()
if h.cpuW == nil {
return errors.New("CPU profiling not in progress")
}
log.Info("Done writing CPU profile", "dump", h.cpuFile)
h.cpuW.Close()
h.cpuW = nil
h.cpuFile = ""
return nil
}
// GoTrace turns on tracing for nsec seconds and writes
// trace data to file.
func (h *HandlerT) GoTrace(file string, nsec uint) error {
if err := h.StartGoTrace(file); err != nil {
return err
}
time.Sleep(time.Duration(nsec) * time.Second)
h.StopGoTrace()
return nil
}
// BlockProfile turns on goroutine profiling for nsec seconds and writes profile data to
// file. It uses a profile rate of 1 for most accurate information. If a different rate is
// desired, set the rate and write the profile manually.
func (*HandlerT) BlockProfile(file string, nsec uint) error {
runtime.SetBlockProfileRate(1)
time.Sleep(time.Duration(nsec) * time.Second)
defer runtime.SetBlockProfileRate(0)
return writeProfile("block", file)
}
// SetBlockProfileRate sets the rate of goroutine block profile data collection.
// rate 0 disables block profiling.
func (*HandlerT) SetBlockProfileRate(rate int) {
runtime.SetBlockProfileRate(rate)
}
// WriteBlockProfile writes a goroutine blocking profile to the given file.
func (*HandlerT) WriteBlockProfile(file string) error {
return writeProfile("block", file)
}
// MutexProfile turns on mutex profiling for nsec seconds and writes profile data to file.
// It uses a profile rate of 1 for most accurate information. If a different rate is
// desired, set the rate and write the profile manually.
func (*HandlerT) MutexProfile(file string, nsec uint) error {
runtime.SetMutexProfileFraction(1)
time.Sleep(time.Duration(nsec) * time.Second)
defer runtime.SetMutexProfileFraction(0)
return writeProfile("mutex", file)
}
// SetMutexProfileFraction sets the rate of mutex profiling.
func (*HandlerT) SetMutexProfileFraction(rate int) {
runtime.SetMutexProfileFraction(rate)
}
// WriteMutexProfile writes a goroutine blocking profile to the given file.
func (*HandlerT) WriteMutexProfile(file string) error {
return writeProfile("mutex", file)
}
// WriteMemProfile writes an allocation profile to the given file.
// Note that the profiling rate cannot be set through the API,
// it must be set on the command line.
func (*HandlerT) WriteMemProfile(file string) error {
return writeProfile("heap", file)
}
// Stacks returns a printed representation of the stacks of all goroutines.
func (*HandlerT) Stacks() string {
buf := new(bytes.Buffer)
pprof.Lookup("goroutine").WriteTo(buf, 2)
return buf.String()
}
// FreeOSMemory returns unused memory to the OS.
func (*HandlerT) FreeOSMemory() {
debug.FreeOSMemory()
}
// SetGCPercent sets the garbage collection target percentage. It returns the previous
// setting. A negative value disables GC.
func (*HandlerT) SetGCPercent(v int) int {
return debug.SetGCPercent(v)
}
func writeProfile(name, file string) error {
p := pprof.Lookup(name)
log.Info("Writing profile records", "count", p.Count(), "type", name, "dump", file)
f, err := os.Create(expandHome(file))
if err != nil {
return err
}
defer f.Close()
return p.WriteTo(f, 0)
}
// expands home directory in file paths.
// ~someuser/tmp will not be expanded.
func expandHome(p string) string {
if strings.HasPrefix(p, "~/") || strings.HasPrefix(p, "~\\") {
home := os.Getenv("HOME")
if home == "" {
if usr, err := user.Current(); err == nil {
home = usr.HomeDir
}
}
if home != "" {
p = home + p[1:]
}
}
return filepath.Clean(p)
}