138 lines
3.2 KiB
Go
138 lines
3.2 KiB
Go
package backup
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import (
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"archive/tar"
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"context"
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"github.com/apex/log"
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gzip "github.com/klauspost/pgzip"
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"github.com/pkg/errors"
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"github.com/remeh/sizedwaitgroup"
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"golang.org/x/sync/errgroup"
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"io"
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"os"
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"runtime"
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"strings"
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"sync"
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)
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type Archive struct {
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sync.Mutex
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TrimPrefix string
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Files *IncludedFiles
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}
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// Creates an archive at dst with all of the files defined in the included files struct.
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func (a *Archive) Create(dst string, ctx context.Context) (os.FileInfo, error) {
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f, err := os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
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if err != nil {
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return nil, errors.WithStack(err)
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}
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defer f.Close()
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maxCpu := runtime.NumCPU() / 2
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if maxCpu > 4 {
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maxCpu = 4
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}
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gzw, _ := gzip.NewWriterLevel(f, gzip.BestSpeed)
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_ = gzw.SetConcurrency(1<<20, maxCpu)
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defer gzw.Flush()
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defer gzw.Close()
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tw := tar.NewWriter(gzw)
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defer tw.Flush()
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defer tw.Close()
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wg := sizedwaitgroup.New(10)
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g, ctx := errgroup.WithContext(ctx)
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// Iterate over all of the files to be included and put them into the archive. This is
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// done as a concurrent goroutine to speed things along. If an error is encountered at
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// any step, the entire process is aborted.
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for _, p := range a.Files.All() {
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p := p
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g.Go(func() error {
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wg.Add()
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defer wg.Done()
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select {
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case <-ctx.Done():
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return errors.WithStack(ctx.Err())
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default:
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return a.addToArchive(p, tw)
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}
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})
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}
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// Block until the entire routine is completed.
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if err := g.Wait(); err != nil {
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f.Close()
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// Attempt to remove the archive if there is an error, report that error to
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// the logger if it fails.
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if rerr := os.Remove(dst); rerr != nil && !os.IsNotExist(rerr) {
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log.WithField("location", dst).Warn("failed to delete corrupted backup archive")
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}
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return nil, errors.WithStack(err)
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}
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st, err := f.Stat()
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if err != nil {
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return nil, errors.WithStack(err)
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}
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return st, nil
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}
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// Adds a single file to the existing tar archive writer.
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func (a *Archive) addToArchive(p string, w *tar.Writer) error {
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f, err := os.Open(p)
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if err != nil {
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// If you try to backup something that no longer exists (got deleted somewhere during the process
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// but not by this process), just skip over it and don't kill the entire backup.
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if os.IsNotExist(err) {
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return nil
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}
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return errors.WithStack(err)
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}
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defer f.Close()
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s, err := f.Stat()
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if err != nil {
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// Same as above, don't kill the process just because the file no longer exists.
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if os.IsNotExist(err) {
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return nil
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}
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return errors.WithStack(err)
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}
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header := &tar.Header{
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// Trim the long server path from the name of the file so that the resulting
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// archive is exactly how the user would see it in the panel file manager.
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Name: strings.TrimPrefix(p, a.TrimPrefix),
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Size: s.Size(),
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Mode: int64(s.Mode()),
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ModTime: s.ModTime(),
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}
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// These actions must occur sequentially, even if this function is called multiple
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// in parallel. You'll get some nasty panic's otherwise.
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a.Lock()
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defer a.Unlock()
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if err := w.WriteHeader(header); err != nil {
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return errors.WithStack(err)
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}
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buf := make([]byte, 4*1024)
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if _, err := io.CopyBuffer(w, f, buf); err != nil {
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return errors.WithStack(err)
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}
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return nil
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}
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