go-简易logger

• 支持按日期划分日志文件
• 支持清除30天前旧日志
• 按需结合io.MultiWriter()实现多输出端显示

package main

import (
    "fmt"
    "io"
    "os"
    "path/filepath"
    "sync"
    "time"
)

type MyLog struct {
    mu       sync.Mutex
    F        *os.File
    Name     string
    Path     string
    CutByDay bool
    date     string
}

func (m *MyLog) Write(c []byte) (int, error) {
    m.mu.Lock()
    defer m.mu.Unlock()
    if m.date != time.Now().Format("2006-01-02") {
        if m.F != nil {
            m.F.Close()
            m.F = nil
        }
    }
    if m.F == nil {
        f, err := os.OpenFile(m.GetLogPath(), os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
        if err != nil {
            return 0, err
        }
        m.F = f
    }
    return m.F.Write(c)
}

func (m *MyLog) Close() {
    if m.F != nil {
        m.F.Close()
    }
}

func (m *MyLog) GetLogPath() string {
    path := m.Path + "/" + m.Name
    if m.CutByDay {
        path += "_" + time.Now().Format("2006-01-02")
    }
    return path + ".log"
}

func (m *MyLog) SetName(n string) {
    m.mu.Lock()
    defer m.mu.Unlock()
    m.Name = n
}

func (m *MyLog) ClearOldLog() {
    m.mu.Lock()
    defer m.mu.Unlock()
    p := m.Path + "/" + m.Name + "*.log"
    matchFiles, err := filepath.Glob(p)
    if err != nil {
        return
    }
    for _, v := range matchFiles {
        nFile := m.Path + "/" + v
        fd, err := os.Stat(nFile)
        if err != nil {
            continue
        }
        fmt.Println(nFile)
        if fd.ModTime().Before(time.Now().AddDate(0, 0, -30)) {
            os.Remove(nFile)
        }
    }
}

func main() {
    m := MyLog{
        Path:     ".",
        Name:     "warn",
        CutByDay: false,
    }
    defer m.Close()

    mw := io.MultiWriter(&m, os.Stdout)
    mw.Write([]byte("hello\n"))
    mw.Write([]byte("the world is very beat\n"))
    m.ClearOldLog()
}