mirror of
https://github.com/offen/docker-volume-backup.git
synced 2024-09-19 21:20:28 +02:00
Frederik Ring
a57e93d01e
* Split code into multiple files * Deduplicate logic for pruning backups against different storages * Only parse templates when notifications are enabled * Use better description
108 lines
2.3 KiB
Go
108 lines
2.3 KiB
Go
// Copyright 2022 - Offen Authors <hioffen@posteo.de>
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// SPDX-License-Identifier: MPL-2.0
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package main
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import (
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"bytes"
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"errors"
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"fmt"
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"io"
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"os"
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"strings"
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"github.com/gofrs/flock"
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)
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var noop = func() error { return nil }
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// lock opens a lockfile at the given location, keeping it locked until the
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// caller invokes the returned release func. When invoked while the file is
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// still locked the function panics.
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func lock(lockfile string) func() error {
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fileLock := flock.New(lockfile)
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acquired, err := fileLock.TryLock()
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if err != nil {
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panic(err)
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}
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if !acquired {
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panic("unable to acquire file lock")
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}
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return fileLock.Unlock
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}
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// copy creates a copy of the file located at `dst` at `src`.
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func copyFile(src, dst string) error {
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in, err := os.Open(src)
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if err != nil {
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return err
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}
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defer in.Close()
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out, err := os.Create(dst)
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if err != nil {
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return err
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}
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_, err = io.Copy(out, in)
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if err != nil {
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out.Close()
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return err
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}
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return out.Close()
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}
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// join takes a list of errors and joins them into a single error
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func join(errs ...error) error {
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if len(errs) == 1 {
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return errs[0]
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}
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var msgs []string
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for _, err := range errs {
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if err == nil {
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continue
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}
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msgs = append(msgs, err.Error())
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}
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return errors.New("[" + strings.Join(msgs, ", ") + "]")
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}
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// remove removes the given file or directory from disk.
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func remove(location string) error {
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fi, err := os.Lstat(location)
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if err != nil {
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if os.IsNotExist(err) {
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return nil
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}
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return fmt.Errorf("remove: error checking for existence of `%s`: %w", location, err)
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}
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if fi.IsDir() {
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err = os.RemoveAll(location)
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} else {
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err = os.Remove(location)
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}
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if err != nil {
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return fmt.Errorf("remove: error removing `%s`: %w", location, err)
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}
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return nil
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}
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// buffer takes an io.Writer and returns a wrapped version of the
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// writer that writes to both the original target as well as the returned buffer
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func buffer(w io.Writer) (io.Writer, *bytes.Buffer) {
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buffering := &bufferingWriter{buf: bytes.Buffer{}, writer: w}
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return buffering, &buffering.buf
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}
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type bufferingWriter struct {
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buf bytes.Buffer
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writer io.Writer
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}
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func (b *bufferingWriter) Write(p []byte) (n int, err error) {
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if n, err := b.buf.Write(p); err != nil {
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return n, fmt.Errorf("bufferingWriter: error writing to buffer: %w", err)
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}
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return b.writer.Write(p)
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}
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