基于golang如何实现error工具包详解

type Error struct {
 err  error
 msg  string
 fullMsg string
 stackTrace
}

func Errf(err error, format string, args ...interface{}) *Error {
 e := &Error{
  err: err,
  msg: fmt.Sprintf(format, args),
 }
 e.fullMsg = e.genFullMsg()
 return e
}

func Err(err error, args ...interface{}) *Error {
 e := &Error{
  err: err,
  msg: fmt.Sprint(args),
 }
 e.fullMsg = e.genFullMsg()
 return e
}

type stackTrace struct {
 // stack info
 data string
 callers []uintptr
}

func (err *Error) getStackTrace() string {
 if strings.TrimSpace(err.data) == "" {
  return err.genStackTrace(5)
 }
 return err.data
}

func (err *Error) StackTrace() string {
 return err.data
}

func (err *Error) genStackTrace(skip int) string {
 if config.isPrintStack == 1 {
  var buffer bytes.Buffer
  buffer.WriteString("StackTrace:\n")
  var st [64]uintptr
  n := runtime.Callers(skip, st[:])
  err.callers = st[:n]
  frames := runtime.CallersFrames(err.callers)
  for {
   frame, ok := frames.Next()
   if !ok {
    break
   }
   if !strings.Contains(frame.File, "runtime/") {
    buffer.WriteString(fmt.Sprintf("%s\n\t%s:%d\n", 
    frame.Func.Name(), frame.File, frame.Line))
   }
  }
  err.data = buffer.String()
  return err.data
 }
 return ""
}

const (
 //print stack info
 PRINTSTACK = 1
)

// global error config object
var config *errConfig = &errConfig{}

// error config
type errConfig struct {
 isPrintStack uint32
}

//set error config info
func SetConfig(conf byte) {
 if (conf & PRINTSTACK) != 0 {
  atomic.CompareAndSwapUint32(&config.isPrintStack, 0, 1)
 }
}

func init() {
 errors.SetConfig(errors.PRINTSTACK)
}

func main() {
 a := func() {
  err := errors.Err(nil, "this is an inner error")
  fmt.Print(err.StackTrace())
  b := errors.Errf(err, "this is a %s message", "test").Error()
  fmt.Println(b)
 }
 a()
}