package main
import (
 "fmt"
 "log"
 "os"
 "os/exec"
 "runtime/debug"
)
// MyError 自定义异常
type MyError struct {
 Inner      error // 最底层的异常 以便在需要时可以查看发生的异常
 Message    string //用户友好信息
 StackTrace string // 堆栈轨迹信息
 Misc       map[string]interface{} // 其他一些自定义信息
}
// 打包错误
func wrapError(err error, messagef string, msgArgs ...interface{}) MyError {
 return MyError{
  Inner:      err,
  Message:    fmt.Sprintf(messagef, msgArgs...),
  StackTrace: string(debug.Stack()),
  Misc:       make(map[string]interface{}),
 }
}
// 实现error接口
func (err MyError) Error() string {
 return err.Message
}
// LowLevelErr 底层error封装
type LowLevelErr struct {
 error
}
func isGloballyExec(path string) (bool, error) {
 info, err := os.Stat(path)
 if err != nil {
  //对最底层的error只是封装，向上层直接传递就行了，这是最基础的错误，不要过多干涉
  return false, LowLevelErr{wrapError(err, err.Error())} 
 }
 return info.Mode().Perm()&0100 == 0100, nil
}
// IntermediateErr 中间层error封装
type IntermediateErr struct {
 error
}
func runJob(id string) error {
 const jobBinPath = "/bad/job/binary"
 isExecutable, err := isGloballyExec(jobBinPath)
 if err != nil {
  // 中间层获取到底层错误之后，再次封装，把底层的error当作内部err处理，但是msg已经是当前中间层的msg了
  return IntermediateErr{wrapError(
   err,
   "cannot run job %q: requisite binaries not available",
   id,
  )}
 } else if isExecutable == false {
  // 如果不是底层异常，那么封装异常的时候err=nil就行，但是因为程序已知的业务逻辑判断
  // 没办法继续执行，那么在封装错误的时候只需要提供msg就可以了
  return wrapError(
   nil,
   "cannot run job %q: requisite binaries are not executable",
   id,
  )
 }
 return exec.Command(jobBinPath, "--id="+id).Run()
}
func handleError(key int, err error, message string) {
 log.SetPrefix(fmt.Sprintf("[logID: %v]: ", key))
 log.Printf("%#v", err) // 处理异常
 fmt.Printf("[%v] %v", key, message) // 用户展示的友好异常信息
}
func main() {
 log.SetOutput(os.Stdout)
 log.SetFlags(log.Ltime | log.LUTC)
 err := runJob("1")
 if err != nil {
  msg := "There was an unexpected issue; please report this as a bug."
  // 在上层调用者这里可以断言是否是我们自定义结构良好的异常，不是的话就是bug
  if _, ok := err.(IntermediateErr); ok {
   msg = err.Error()
  }
  // 处理error
  handleError(1, err, msg)
 }
}

异常信息：
[logID: 1]: 04:20:20 main.IntermediateErr{error:main.MyError{Inner:main.LowLevelErr{error:main.MyError{Inner:(*fs.PathError)(0xc00006c180), Message:"stat /bad/job/binary: no such file or directory", StackTrace:"goroutine 1 [running]:\nruntime/debug.Stack(0xc0000161e0, 0x2f, 0x0)\n\t/Users/jamlee/sdk/go1.16.8/src/runtime/debug/stack.go:24 +0x9f\nmain.wrapError(0x11021d0, 0xc00006c180, 0xc0000161e0, 0x2f, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, ...)\n\t/Users/jamlee/go/src/awesomeProject/at_scale/main.go:24 +0xb4\nmain.isGloballyExec(0x10e0c86, 0xf, 0x0, 0x0, 0x1012c1b)\n\t/Users/jamlee/go/src/awesomeProject/at_scale/main.go:44 +0xc5\nmain.runJob(0x10df348, 0x1, 0x1018301, 0x0)\n\t/Users/jamlee/go/src/awesomeProject/at_scale/main.go:56 +0x48\nmain.main()\n\t/Users/jamlee/go/src/awesomeProject/at_scale/main.go:87 +0x70\n", Misc:map[string]interface {}{}}}, Message:"cannot run job \"1\": requisite binaries not available", StackTrace:"goroutine 1 [running]:\nruntime/debug.Stack(0x10e6a6c, 0x33, 0xc000068ed8)\n\t/Users/jamlee/sdk/go1.16.8/src/runtime/debug/stack.go:24 +0x9f\nmain.wrapError(0x11022f0, 0xc0000102a0, 0x10e6a6c, 0x33, 0xc000068ed8, 0x1, 0x1, 0x0, 0x0, 0x0, ...)\n\t/Users/jamlee/go/src/awesomeProject/at_scale/main.go:24 +0xb4\nmain.runJob(0x10df348, 0x1, 0x1018301, 0x0)\n\t/Users/jamlee/go/src/awesomeProject/at_scale/main.go:59 +0x2dc\nmain.main()\n\t/Users/jamlee/go/src/awesomeProject/at_scale/main.go:87 +0x70\n", Misc:map[string]interface {}{}}}
//给用户展示的信息
[1] cannot run job "1": requisite binaries not available