func (d *Btrfs) Subvolumes(config config.Config) ([]string, error) {
var stderr bytes.Buffer
var stdout bytes.Buffer
cmd := exec.Command("btrfs", "subvolume", "list", config.Subvolume())
cmd.Stderr = &stderr
cmd.Stdout = &stdout
log.Printf("Getting subvolume list for: %s", config.Subvolume())
if err := cmd.Start(); err != nil {
return nil, err
}
if err := cmd.Wait(); err != nil {
err = fmt.Errorf("Error getting subvolume list: %s\nStderr: %s",
err, stderr.String())
return nil, err
}
output := stdout.String()
// partition output into slice
subvols := strings.Split(output, "\n")[0 : len(strings.Split(output, "\n"))-1]
return subvols, nil
}
func (d *Btrfs) Prepare(config config.Config) error {
// test to see if subvolume is a valid btrfs file system
var stderr bytes.Buffer
cmd := exec.Command("btrfs", "subvolume", "show", config.Subvolume())
cmd.Stderr = &stderr
log.Printf("Checking to see if valid subvolume: %s", config.Subvolume())
if err := cmd.Start(); err != nil {
return err
}
if err := cmd.Wait(); err != nil {
err = fmt.Errorf("Error checking for a valid subvolume: %s\nStderr: %s",
err, stderr.String())
return err
}
// all good, is a valid subvolume
log.Printf("Valid subvolume found: %s", config.Subvolume())
return nil
}
func (d *Btrfs) Snapshot(config config.Config, srcSnapshot string) (string, error) {
snapshot_dir := config.Subvolume() + "/" + config.SubvolumeDirectory()
t := time.Now()
timestamp := t.Format("20060102150405")
snapshot := snapshot_dir + "/btrfs_backup_" + timestamp
log.Printf("Making sure of the source directory: %s", srcSnapshot)
var stderr bytes.Buffer
cmd := exec.Command("btrfs", "subvolume", "show", srcSnapshot)
cmd.Stderr = &stderr
if err := cmd.Start(); err != nil {
return "", err
}
if err := cmd.Wait(); err != nil {
err = fmt.Errorf("Error checking for a valid subvolume: %s\nStderr: %s",
err, stderr.String())
return "", err
}
log.Printf("Valid subvolume found: %s", srcSnapshot)
log.Printf("Making sure of the destination directory: %s", snapshot_dir)
create_destination := false
var stderr3 bytes.Buffer
cmd = exec.Command("btrfs", "subvolume", "show", snapshot_dir)
cmd.Stderr = &stderr3
if err := cmd.Start(); err != nil {
return "", err
}
if err := cmd.Wait(); err != nil {
create_destination = true
}
if create_destination == true {
log.Printf("Error in verifying the destination subvolume %s, trying to create it", snapshot_dir)
new_volume, err_create := d.CreateSubvolume(snapshot_dir)
if new_volume == snapshot_dir && err_create == nil {
log.Printf("New subvolume created: %s", snapshot_dir)
} else {
err_create = fmt.Errorf("Error creating new subvolume. \nStderr: %s",
err_create)
return "", err_create
}
}
log.Printf("Valid subvolume found: %s", snapshot_dir)
// all good, is a valid subvolume source and destination
log.Printf("Creating snapshot in: %s", snapshot)
var stderr2 bytes.Buffer
cmd = exec.Command("btrfs", "subvolume", "snapshot", "-r", srcSnapshot, snapshot)
cmd.Stderr = &stderr2
if err := cmd.Start(); err != nil {
return "", err
}
if err := cmd.Wait(); err != nil {
err = fmt.Errorf("Error creating snapshot: %s\nStderr: %s",
err, stderr2.String())
return "", err
}
cmd = exec.Command("sync", snapshot_dir)
cmd.Stderr = &stderr2
if err := cmd.Start(); err != nil {
return "", err
}
if err := cmd.Wait(); err != nil {
err = fmt.Errorf("Error running filesystem sync: %s\nStderr: %s",
err, stderr2.String())
return "", err
}
log.Printf("Snapshot created: %s from %s", snapshot, srcSnapshot)
return snapshot, nil
}