96 lines
2.2 KiB
Go
96 lines
2.2 KiB
Go
package backup
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import (
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"errors"
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"io"
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"os"
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"path/filepath"
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"sync"
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)
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// LogWriter 保留三份各不超过 10 MiB 的应用日志，权限 0600。
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type LogWriter struct {
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mu sync.Mutex
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dir string
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file *os.File
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size int64
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}
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func OpenLog(dir string) (*LogWriter, error) {
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if err := os.MkdirAll(dir, 0700); err != nil {
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return nil, err
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}
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f, err := os.OpenFile(filepath.Join(dir, "rawmark.log"), os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0600)
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if err != nil {
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return nil, err
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}
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info, err := f.Stat()
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if err != nil {
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f.Close()
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return nil, err
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}
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return &LogWriter{dir: dir, file: f, size: info.Size()}, nil
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}
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func (l *LogWriter) Write(p []byte) (int, error) {
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l.mu.Lock()
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defer l.mu.Unlock()
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if len(p) > 10<<20 {
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return 0, errors.New("单条日志超过大小上限")
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}
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if l.size+int64(len(p)) > 10<<20 {
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if err := l.file.Close(); err != nil {
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return 0, err
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}
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for i := 2; i >= 1; i-- {
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dest := filepath.Join(l.dir, "rawmark.log.2")
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src := filepath.Join(l.dir, "rawmark.log.1")
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if i == 1 {
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dest = src
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src = filepath.Join(l.dir, "rawmark.log")
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}
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if err := os.Rename(src, dest); err != nil && !errors.Is(err, os.ErrNotExist) {
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return 0, err
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}
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}
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f, err := os.OpenFile(filepath.Join(l.dir, "rawmark.log"), os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0600)
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if err != nil {
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return 0, err
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}
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l.file = f
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l.size = 0
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}
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n, err := l.file.Write(p)
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l.size += int64(n)
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return n, err
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}
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func (l *LogWriter) Close() error { l.mu.Lock(); defer l.mu.Unlock(); return l.file.Close() }
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// Snapshot 读取当前日志的稳定副本，避免导出与日志轮转竞争。
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func (l *LogWriter) Snapshot(dest string) error {
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l.mu.Lock()
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defer l.mu.Unlock()
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if err := l.file.Sync(); err != nil {
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return err
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}
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for _, name := range []string{"rawmark.log", "rawmark.log.1", "rawmark.log.2"} {
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src, err := os.Open(filepath.Join(l.dir, name))
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if errors.Is(err, os.ErrNotExist) {
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continue
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}
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if err != nil {
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return err
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}
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out, err := os.OpenFile(filepath.Join(dest, name), os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0600)
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if err != nil {
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src.Close()
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return err
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}
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_, err = io.Copy(out, src)
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err = errors.Join(err, src.Close(), out.Close())
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if err != nil {
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return err
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}
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}
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return nil
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}
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