[go]zap配合logrotate实现日志滚动
zap是Uber 提供的GoLang高性能日志库，zap 本身并不提供日志滚动功能，官方 FAQ 提到，可以使用Linux系统自带的 logrotate 或lumberjack实现日志滚动功能
lumberjack 只能向文件输出日志，如果我们希望同时向stderr 和文件输出日志，只能使用 logrotate 配合自定义 WriteSyncer 实现了
Go代码
package main
import (
"bufio"
"context"
"fmt"
"go.uber.org/zap"
"go.uber.org/zap/zapcore"
"os"
"os/signal"
"sync"
"syscall"
)
type LogWriter struct {
FileName string
fp *os.File
mu sync.Mutex
fileCnt int
sig chan os.Signal
ctx context.Context
cancel context.CancelFunc
}
func (m *LogWriter) Write(p []byte) (n int, err error) {
m.mu.Lock()
defer m.mu.Unlock()
if m.fp == nil {
if err := m.open(); err != nil {
return 0, nil
}
}
if m.fileCnt == 0 {
m.fileCnt++
m.ctx, m.cancel = context.WithCancel(context.Background())
m.sig = make(chan os.Signal, 1)
signal.Notify(m.sig, syscall.SIGHUP)
go func() {
for {
select {
case <-m.ctx.Done():
return
case _, ok := <-m.sig:
if ok == false {
return
}
func() {
m.mu.Lock()
defer m.mu.Unlock()
if m.fp != nil {
_ = m.fp.Close()
m.fp = nil
}
}()
}
}
}()
}
_, _ = os.Stderr.Write(p)
return m.fp.Write(p)
}
func (m *LogWriter) Sync() error {
m.mu.Lock()
defer m.mu.Unlock()
_ = os.Stderr.Sync()
return m.fp.Sync()
}
func (m *LogWriter) Close() error {
m.mu.Lock()
defer m.mu.Unlock()
m.cancel()
if m.fp != nil {
if err := m.fp.Close(); err != nil {
return err
}
}
if m.sig != nil {
signal.Reset(syscall.SIGHUP)
close(m.sig)
}
return nil
}
func (m *LogWriter) open() error {
if m.fp != nil {
if err := m.fp.Sync(); err != nil {
return err
}
if err := m.fp.Close(); err != nil {
return err
}
}
fp, err := os.OpenFile(m.FileName, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0644)
if err != nil {
return err
}
m.fp = fp
return nil
}
func main() {
zapid, _ := os.OpenFile("/tmp/zap.pid", os.O_CREATE|os.O_WRONLY, 0644)
_, _ = zapid.WriteString(fmt.Sprintf("%d", os.Getpid()))
_ = zapid.Sync()
_ = syscall.Flock(int(zapid.Fd()), syscall.LOCK_EX)
mylog := &LogWriter{
FileName: "/tmp/zap.log"}
cfg := zap.NewProductionEncoderConfig()
cfg.EncodeTime = zapcore.ISO8601TimeEncoder
core := zapcore.NewCore(zapcore.NewJSONEncoder(cfg), mylog, zap.InfoLevel)
logger := zap.New(core)
reader := bufio.NewReader(os.Stdin)
for i := 0; i < 10; i++ {
logger.Debug("debug msg", zap.Int("idx", i))
logger.Info("info msg", zap.Int("idx", i))
logger.Error("error msg", zap.Int("idx", i))
logger.Warn("warn msg", zap.Int("idx", i))
fmt.Printf("====================")
_, _, _ = reader.ReadRune()
}
_ = mylog.Close()
_ = syscall.Flock(int(zapid.Fd()), syscall.LOCK_UN)
_ = zapid.Close()
}
编译生成测试程序 zap_exp
go build zap_exp.go
logrotate 配置文件
/tmp/zap.log {
su robin robin
missingok
daily
minsize 1M
create 0644 robin robin
rotate 12
postrotate
PIDFILE=/tmp/zap.pid
if [ -f "$PIDFILE" ] ; then kill -HUP $(cat "$PIDFILE") ; fi
endscript
}
zap.conf 的 owner 和 group 必须为 root，并且 file mode 为 0644 ，只有 root 可以读写，其它只读
su robin robin: 运行zap_exp程序的用户名及坐在的Group，本测试中user和group均为robincreate 0644 robin robin: 日志滚动后，重新生成日志文件的file mode及ower和grouppostrotate: 需要配合zap_exp.go源码分析zap_exp.go在main函数启动后首先生成/tmp/zap.pid文件，然后将当前程序的pid写入该文件，并锁定该文件LogWriter设置signal.Notify(m.sig, syscall.SIGHUP)表明zap_exp程序接受HUP信号LogWriter收到HUP信号后关闭当前日志文件LogWriter写日志文件时，如果日志文件被关闭，程序自动重新创建logrotate程序运行时，首先从/tmp/zap.pid文件读取zap_exp程序的pid，然后向zap_exp程序发送HUP信号
测试
运行 zap_exp 程序，分别在 idx:3 和 idx:6 时手动强制执行 logrotate 程序
logrotate -s ./log.status -vf ./zap.conf
zap_exp 运行结果
./zap_exp
{
"level":"info","ts":"2020-09-10T16:53:54.896+0800","msg":"info msg","idx":0}
{
"level":"error","ts":"2020-09-10T16:53:54.896+0800","msg":"error msg","idx":0}
{
"level":"warn","ts":"2020-09-10T16:53:54.896+0800","msg":"warn msg","idx":0}
====================
{
"level":"info","ts":"2020-09-10T16:53:56.628+0800","msg":"info msg","idx":1}
{
"level":"error","ts":"2020-09-10T16:53:56.628+0800","msg":"error msg","idx":1}
{
"level":"warn","ts":"2020-09-10T16:53:56.628+0800","msg":"warn msg","idx":1}
====================
{
"level":"info","ts":"2020-09-10T16:53:57.060+0800","msg":"info msg","idx":2}
{
"level":"error","ts":"2020-09-10T16:53:57.060+0800","msg":"error msg","idx":2}
{
"level":"warn","ts":"2020-09-10T16:53:57.060+0800","msg":"warn msg","idx":2}
====================
{
"level":"info","ts":"2020-09-10T16:53:57.393+0800","msg":"info msg","idx":3}
{
"level":"error","ts":"2020-09-10T16:53:57.393+0800","msg":"error msg","idx":3}
{
"level":"warn","ts":"2020-09-10T16:53:57.393+0800","msg":"warn msg","idx":3}
====================
{
"level":"info","ts":"2020-09-10T16:54:31.706+0800","msg":"info msg","idx":4}
{
"level":"error","ts":"2020-09-10T16:54:31.706+0800","msg":"error msg","idx":4}
{
"level":"warn","ts":"2020-09-10T16:54:31.706+0800","msg":"warn msg","idx":4}
====================
{
"level":"info","ts":"2020-09-10T16:54:32.050+0800","msg":"info msg","idx":5}
{
"level":"error","ts":"2020-09-10T16:54:32.050+0800","msg":"error msg","idx":5}
{
"level":"warn","ts":"2020-09-10T16:54:32.050+0800","msg":"warn msg","idx":5}
====================
{
"level":"info","ts":"2020-09-10T16:54:32.359+0800","msg":"info msg","idx":6}
{
"level":"error","ts":"2020-09-10T16:54:32.359+0800","msg":"error msg","idx":6}
{
"level":"warn","ts":"2020-09-10T16:54:32.359+0800","msg":"warn msg","idx":6}
====================
{
"level":"info","ts":"2020-09-10T16:54:36.955+0800","msg":"info msg","idx":7}
{
"level":"error","ts":"2020-09-10T16:54:36.956+0800","msg":"error msg","idx":7}
{
"level":"warn","ts":"2020-09-10T16:54:36.956+0800","msg":"warn msg","idx":7}
====================
{
"level":"info","ts":"2020-09-10T16:54:37.255+0800","msg":"info msg","idx":8}
{
"level":"error","ts":"2020-09-10T16:54:37.255+0800","msg":"error msg","idx":8}
{
"level":"warn","ts":"2020-09-10T16:54:37.255+0800","msg":"warn msg","idx":8}
====================
{
"level":"info","ts":"2020-09-10T16:54:37.712+0800","msg":"info msg","idx":9}
{
"level":"error","ts":"2020-09-10T16:54:37.712+0800","msg":"error msg","idx":9}
{
"level":"warn","ts":"2020-09-10T16:54:37.712+0800","msg":"warn msg","idx":9}
====================
在 /tmp 可以找到如下3个文件 zap.log zap.log.1 zap.log.2
zap.log.2 内容如下，刚好对应 idx:3 时执行 logrotate 时产生的日志滚动
{"level":"info","ts":"2020-09-10T16:53:54.896+0800","msg":"info msg","idx":0}
{"level":"error","ts":"2020-09-10T16:53:54.896+0800","msg":"error msg","idx":0}
{"level":"warn","ts":"2020-09-10T16:53:54.896+0800","msg":"warn msg","idx":0}
{"level":"info","ts":"2020-09-10T16:53:56.628+0800","msg":"info msg","idx":1}
{"level":"error","ts":"2020-09-10T16:53:56.628+0800","msg":"error msg","idx":1}
{"level":"warn","ts":"2020-09-10T16:53:56.628+0800","msg":"warn msg","idx":1}
{"level":"info","ts":"2020-09-10T16:53:57.060+0800","msg":"info msg","idx":2}
{"level":"error","ts":"2020-09-10T16:53:57.060+0800","msg":"error msg","idx":2}
{"level":"warn","ts":"2020-09-10T16:53:57.060+0800","msg":"warn msg","idx":2}
{"level":"info","ts":"2020-09-10T16:53:57.393+0800","msg":"info msg","idx":3}
{"level":"error","ts":"2020-09-10T16:53:57.393+0800","msg":"error msg","idx":3}
{"level":"warn","ts":"2020-09-10T16:53:57.393+0800","msg":"warn msg","idx":3}
参考资料
- zap FAQ
- zap github issue : use with linux logrotate