zap源码浏览(2)
上篇文章次要是介绍了zap库的构造和性能劣势，然而其提供的只是根底的日志写入性能，理论工作须要日志具备大小切割，日志压缩，保留指定天数等性能，此时就须要应用另外一个开源库lumberjack(https://github.com/natefinch/...
1. lumberjack 库介绍
Logger构造体
type Logger struct { Filename string `json:"filename" yaml:"filename"` //文件名 MaxSize int `json:"maxsize" yaml:"maxsize"` // 最大保留文件大小，默认100M MaxAge int `json:"maxage" yaml:"maxage"` // 最大保留天数 MaxBackups int `json:"maxbackups" yaml:"maxbackups"` // 最大保留个数 LocalTime bool `json:"localtime" yaml:"localtime"` //文件以工夫命名的格局 Compress bool `json:"compress" yaml:"compress"` // 是否压缩 size int64 // 以后文件大小 file *os.File mu sync.Mutex millCh chan bool startMill sync.Once}该库对外提供的接口比较简单，次要是Write函数。
func (l *Logger) Write(p []byte) (n int, err error) { l.mu.Lock() defer l.mu.Unlock() writeLen := int64(len(p)) if writeLen > l.max() { // 字节长度超过单个文件最大值 return 0, fmt.Errorf( "write length %d exceeds maximum file size %d", writeLen, l.max(), ) } if l.file == nil { // 没有指定保留文件名, 创立一个 if err = l.openExistingOrNew(len(p)); err != nil { return 0, err } } if l.size+writeLen > l.max() { // 单个文件大于指定的最大值，须要拆分 if err := l.rotate(); err != nil { return 0, err } } n, err = l.file.Write(p) // 失常的文件写入内容 l.size += int64(n) return n, err}openExistingOrNew 函数
func (l *Logger) openExistingOrNew(writeLen int) error { l.mill() filename := l.filename()//写入日志的文件,带有门路 info, err := osStat(filename) //查看日志文件状态 if os.IsNotExist(err) { // 依据谬误后果，看看是否须要新建文件。 return l.openNew() } if err != nil { return fmt.Errorf("error getting log file info: %s", err) } if info.Size()+int64(writeLen) >= l.max() { // 原有的日志文件加上要写的字节大于要求的最大值就拆分 return l.rotate() } file, err := os.OpenFile(filename, os.O_APPEND|os.O_WRONLY, 0644) //以追加和只写的模式关上已有的文件 if err != nil { // if we fail to open the old log file for some reason, just ignore // it and open a new log file. return l.openNew() } l.file = file l.size = info.Size() return nil}openNew函数,创立新的文件
func (l *Logger) openNew() error { err := os.MkdirAll(l.dir(), 0755) if err != nil { return fmt.Errorf("can't make directories for new logfile: %s", err) } name := l.filename() mode := os.FileMode(0600) info, err := osStat(name) if err == nil { // Copy the mode off the old logfile. mode = info.Mode() // move the existing file newname := backupName(name, l.LocalTime) // 以原始名称创立一个带工夫戳的文件名 if err := os.Rename(name, newname); err != nil { //更名原来的文件 return fmt.Errorf("can't rename log file: %s", err) } // this is a no-op anywhere but linux if err := chown(name, info); err != nil { //以清空文件内容来创立新文件 return err } } // we use truncate here because this should only get called when we've moved // the file ourselves. if someone else creates the file in the meantime, // 从新关上文件 f, err := os.OpenFile(name, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, mode) if err != nil { return fmt.Errorf("can't open new logfile: %s", err) } l.file = f l.size = 0 return nil}var osChown = os.Chownfunc chown(name string, info os.FileInfo) error { f, err := os.OpenFile(name, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, info.Mode()) if err != nil { return err } f.Close()// 敞开文件 stat := info.Sys().(*syscall.Stat_t) return osChown(name, int(stat.Uid), int(stat.Gid)) //调配组}rotate 函数:
func (l *Logger) rotate() error { // 该函数并不是每个文件必须写满MaxSize, 当要写的日志大于MaxSize, 之前的日志文件不会再写，之后的文件以最新的文件开始写. if err := l.close(); err != nil { // 先关掉之前的文件 return err } if err := l.openNew(); err != nil { // 创立新的文件 return err } l.mill() return nil}mill 函数:
func (l *Logger) mill() { l.startMill.Do(func() { l.millCh = make(chan bool, 1) go l.millRun() // 开启协程 }) select { case l.millCh <- true: // 每次Write都会告诉协程做事件。 default: }}func (l *Logger) millRun() { for range l.millCh { // 读millCh channel事件 _ = l.millRunOnce() }}日志切割外围函数millRunOnce:
func (l *Logger) millRunOnce() error { if l.MaxBackups == 0 && l.MaxAge == 0 && !l.Compress { return nil } files, err := l.oldLogFiles() //获取该目录下的所有符合条件的文件 if err != nil { return err } var compress, remove []logInfo if l.MaxBackups > 0 && l.MaxBackups < len(files) {// 超过须要保留的最大文件数 preserved := make(map[string]bool) var remaining []logInfo for _, f := range files { // Only count the uncompressed log file or the // compressed log file, not both. fn := f.Name() if strings.HasSuffix(fn, compressSuffix) { fn = fn[:len(fn)-len(compressSuffix)] } preserved[fn] = true if len(preserved) > l.MaxBackups { remove = append(remove, f) } else { remaining = append(remaining, f) //保留最近工夫的指定数量文件 } } files = remaining } if l.MaxAge > 0 { diff := time.Duration(int64(24*time.Hour) * int64(l.MaxAge)) cutoff := currentTime().Add(-1 * diff) var remaining []logInfo for _, f := range files { if f.timestamp.Before(cutoff) { remove = append(remove, f) } else { remaining = append(remaining, f) //保留最近工夫的日志 } } files = remaining } if l.Compress { for _, f := range files { if !strings.HasSuffix(f.Name(), compressSuffix) { compress = append(compress, f) // 须要压缩的文件 } } } for _, f := range remove { //删除不满足条件的文件 errRemove := os.Remove(filepath.Join(l.dir(), f.Name())) if err == nil && errRemove != nil { err = errRemove } } for _, f := range compress { // 对须要压缩的文件进行压缩解决 fn := filepath.Join(l.dir(), f.Name()) errCompress := compressLogFile(fn, fn+compressSuffix) if err == nil && errCompress != nil { err = errCompress } } return err}func (l *Logger) oldLogFiles() ([]logInfo, error) { files, err := ioutil.ReadDir(l.dir()) //目录下的所有文件 if err != nil { return nil, fmt.Errorf("can't read log file directory: %s", err) } logFiles := []logInfo{} prefix, ext := l.prefixAndExt() for _, f := range files { if f.IsDir() { continue } if t, err := l.timeFromName(f.Name(), prefix, ext); err == nil { logFiles = append(logFiles, logInfo{t, f}) //符合条件的文件 continue } if t, err := l.timeFromName(f.Name(), prefix, ext+compressSuffix); err == nil { logFiles = append(logFiles, logInfo{t, f}) //符合条件的压缩文件 continue } // error parsing means that the suffix at the end was not generated // by lumberjack, and therefore it's not a backup file. } sort.Sort(byFormatTime(logFiles)) //以最近工夫的日志排在后面 return logFiles, nil}压缩办法compressLogFile:
func compressLogFile(src, dst string) (err error) { f, err := os.Open(src) if err != nil { return fmt.Errorf("failed to open log file: %v", err) } defer f.Close() fi, err := osStat(src) if err != nil { return fmt.Errorf("failed to stat log file: %v", err) } if err := chown(dst, fi); err != nil { return fmt.Errorf("failed to chown compressed log file: %v", err) } // If this file already exists, we presume it was created by // a previous attempt to compress the log file. gzf, err := os.OpenFile(dst, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, fi.Mode()) if err != nil { return fmt.Errorf("failed to open compressed log file: %v", err) } defer gzf.Close() gz := gzip.NewWriter(gzf) defer func() { if err != nil { os.Remove(dst) err = fmt.Errorf("failed to compress log file: %v", err) } }() if _, err := io.Copy(gz, f); err != nil { return err } if err := gz.Close(); err != nil { return err } if err := gzf.Close(); err != nil { return err } if err := f.Close(); err != nil { return err } if err := os.Remove(src); err != nil { return err } return nil}