Get last error with stack

last-error-with-stack.go

// import gihub.com/pkg/errors
// Stack returns the last error in the error chain implementing StackTrace() or nil iа no errors with stack trace  
func Stack(err error) errors.StackTrace {
	type (
    causer interface {
      Cause() error
    }
	  stackTracer interface {
      StackTrace() errors.StackTrace
    }
  )

	var stackErr error
	for {
		if _, ok := err.(stackTracer); ok {
			stackErr = err
		}

		if causer, ok := err.(causer); ok {
			err = causer.Cause()
		} else {
			break
		}
	}

	if stackErr != nil {
		return stackErr.(stackTracer).StackTrace()
	}

	return nil
}