go 自定义error

package main

import (
    "fmt"
    "os"
    "time"
)

type PathError struct {
    path      string
    op        string
    creatTime string
    message   string
}

func (p *PathError) Error() string {
    return fmt.Sprintf("path=%s \nop=%s \ncreateTime=%s \nmessage=%s", p.path, p.op, p.creatTime, p.message)
}

func Open(fileName string) error {
    file, err := os.Open(fileName)
    if err != nil {
        return &PathError{
            path:      fileName,
            op:        "read",
            message:   err.Error(),
            creatTime: fmt.Sprintf("%v", time.Now()),
        }
    }
    defer file.Close()
    return nil
}

func main() {
    err := Open("/gocode/github.com/passwd01/studygo/golang/test.txt")
    switch v := err.(type) {
    case *PathError:
        fmt.Println("get path error,", v)
    default:

    }
}

╰ go run main.go                                                   -╯
get path error, path=/gocode/github.com/passwd01/studygo/golang/test.txt 
op=read 
createTime=2022-09-14 15:13:27.80366 +0800 CST m=+0.000191561 
message=open /gocode/github.com/passwd01/studygo/golang/test.txt: no such file or directory