Golang实现redis系列-(1)日志组件的封装

package log
import (
  "fmt"
  "io"
  "log"
  "os"
  "strconv"
  "sync"
  "time"
)
// Settings 存储logger的配置信息，为func Setup提供配置
type Settings struct {
  //文件所在路径
  Path string
  //文件名
  Name string
  //文件后缀
  Ext string
  //时间格式
  TimeFormat string
  //文件夹内文件最大数量
  MaxBackups uint32
  //文件的大小(k)
  MaxSize uint32
  //用于计数到第几个文件
  Cnt int
}
var (
  logger             *log.Logger
  defaultPrefix      = ""
  defaultCallerDepth = 2
  mu                 sync.Mutex
  logPrefix          = ""
  levelFlags         = []string{"ERROR", "FATAL"}
  flags              = log.LstdFlags | log.Lmicroseconds | log.Lshortfile
  filePCB            *os.File
  config             *Settings
  fileStat           os.FileInfo
)
type logLevel int
// log levels
const (
  ERROR logLevel = iota
  FATAL
)
func init() {
  logger = log.New(os.Stdout, defaultPrefix, flags)
}
//检查目录是否存在，true为不存在
func checkNotExist(src string) bool {
  _, err := os.Stat(src)
  return os.IsNotExist(err)
}
//检查目录是否有权限，true为没权限
func checkNotPermission(src string) bool {
  _, err := os.Stat(src)
  return os.IsPermission(err)
}
func isNotExistMkDir(src string) error {
  if notExist := checkNotExist(src); notExist {
    if err := mkDir(src); err != nil {
      return err
    }
  }
  return nil
}
func mkDir(src string) error {
  err := os.MkdirAll(src, os.ModePerm) //Unix permission bits, 0o777
  if err != nil {
    return err
  }
  return nil
}
func mustOpen(fileName, dir string) (*os.File, error) {
  perm := checkNotPermission(dir)
  if perm {
    return nil, fmt.Errorf("permission denied dir: %s", dir)
  }
  err := isNotExistMkDir(dir)
  if err != nil {
    return nil, fmt.Errorf("error during make dir %s, err: %s", dir, err)
  }
  f, err := os.OpenFile(dir+string(os.PathSeparator)+fileName, os.O_TRUNC|os.O_CREATE|os.O_RDWR, 0644)
  if err != nil {
    return nil, fmt.Errorf("fail to open file, err: %s", err)
  }
  return f, nil
}
// Setup 配置logger
func Setup(settings *Settings) {
  config = settings
  if settings.Cnt == 11 {
    settings.Cnt = 1
  }
  if filePCB != nil {
    filePCB.Close()
    filePCB = nil
  }
  dir := settings.Path + time.Now().Format(settings.TimeFormat)
  fileName := fmt.Sprintf("%s_%s.%s",
    settings.Name,
    strconv.Itoa(settings.Cnt),
    settings.Ext)
  logFile, err := mustOpen(fileName, dir)
  if err != nil {
    log.Fatalf("logging.Setup err: %s", err)
  }
  filePCB = logFile
  mw := io.MultiWriter(os.Stdout, logFile)
  logger = log.New(mw, defaultPrefix, flags)
  settings.Cnt++
}
//写入文件时检查文件大小和日期(mustOpen中其实已经会检查日期了)
func checkFileSize() {
  fileStat, _ = filePCB.Stat()
  if fileStat.Size() > int64(config.MaxSize*1024) {
    Setup(config)
  }
}
//设置logger的前缀
func setPrefix(level logLevel) {
  logPrefix = fmt.Sprintf("[%s] ", levelFlags[level])
  logger.SetPrefix(logPrefix)
}
func Error(v ...interface{}) {
  mu.Lock()
  defer mu.Unlock()
  setPrefix(ERROR)
  checkFileSize()
  logger.Println(v...)
}
// Fatal 打印错误日志，然后停止程序
func Fatal(v ...interface{}) {
  mu.Lock()
  defer mu.Unlock()
  setPrefix(FATAL)
  checkFileSize()
  logger.Fatalln(v...)
}