diff --git a/worker/btrfs_snapshot_hook.go b/worker/btrfs_snapshot_hook.go new file mode 100644 index 0000000..50451f7 --- /dev/null +++ b/worker/btrfs_snapshot_hook.go @@ -0,0 +1,90 @@ +package worker + +import ( + "fmt" + "os" + "path/filepath" + + "github.com/dennwc/btrfs" +) + +type btrfsSnapshotHook struct { + provider mirrorProvider + mirrorSnapshotPath string +} + +// the user who runs the jobs (typically `tunasync`) should be granted the permission to run btrfs commands +// TODO: check if the filesystem is Btrfs +func newBtrfsSnapshotHook(provider mirrorProvider, snapshotPath string, mirror mirrorConfig) *btrfsSnapshotHook { + mirrorSnapshotPath := mirror.SnapshotPath + if mirrorSnapshotPath == "" { + mirrorSnapshotPath = filepath.Join(snapshotPath, provider.Name()) + } + return &btrfsSnapshotHook{ + provider: provider, + mirrorSnapshotPath: mirrorSnapshotPath, + } +} + +// check if path `snapshotPath/providerName` exists +// Case 1: Not exists => create a new subvolume +// Case 2: Exists as a subvolume => nothing to do +// Case 3: Exists as a directory => error detected +func (h *btrfsSnapshotHook) preJob() error { + path := h.provider.WorkingDir() + if _, err := os.Stat(path); os.IsNotExist(err) { + // create subvolume + err := btrfs.CreateSubVolume(path) + if err != nil { + logger.Errorf("failed to create Btrfs subvolume %s: %s", path, err.Error()) + return err + } + logger.Noticef("created new Btrfs subvolume %s", path) + } else { + if is, err := btrfs.IsSubVolume(path); err != nil { + return err + } else if !is { + return fmt.Errorf("path %s exists but isn't a Btrfs subvolume", path) + } + } + return nil +} + +func (h *btrfsSnapshotHook) preExec() error { + return nil +} + +func (h *btrfsSnapshotHook) postExec() error { + return nil +} + +// delete old snapshot if exists, then create a new snapshot +func (h *btrfsSnapshotHook) postSuccess() error { + if _, err := os.Stat(h.mirrorSnapshotPath); !os.IsNotExist(err) { + isSubVol, err := btrfs.IsSubVolume(h.mirrorSnapshotPath) + if err != nil { + return err + } else if !isSubVol { + return fmt.Errorf("path %s exists and isn't a Btrfs snapshot", h.mirrorSnapshotPath) + } + // is old snapshot => delete it + if err := btrfs.DeleteSubVolume(h.mirrorSnapshotPath); err != nil { + logger.Errorf("failed to delete old Btrfs snapshot %s", h.mirrorSnapshotPath) + return err + } + logger.Noticef("deleted old snapshot %s", h.mirrorSnapshotPath) + } + // create a new writable snapshot + // (the snapshot is writable so that it can be deleted easily) + if err := btrfs.SnapshotSubVolume(h.provider.WorkingDir(), h.mirrorSnapshotPath, false); err != nil { + logger.Errorf("failed to create new Btrfs snapshot %s", h.mirrorSnapshotPath) + return err + } + logger.Noticef("created new Btrfs snapshot %s", h.mirrorSnapshotPath) + return nil +} + +// keep the old snapshot => nothing to do +func (h *btrfsSnapshotHook) postFail() error { + return nil +} diff --git a/worker/config.go b/worker/config.go index c4346cd..d33153e 100644 --- a/worker/config.go +++ b/worker/config.go @@ -33,14 +33,15 @@ func (p *providerEnum) UnmarshalText(text []byte) error { // Config represents worker config options type Config struct { - Global globalConfig `toml:"global"` - Manager managerConfig `toml:"manager"` - Server serverConfig `toml:"server"` - Cgroup cgroupConfig `toml:"cgroup"` - ZFS zfsConfig `toml:"zfs"` - Docker dockerConfig `toml:"docker"` - Include includeConfig `toml:"include"` - Mirrors []mirrorConfig `toml:"mirrors"` + Global globalConfig `toml:"global"` + Manager managerConfig `toml:"manager"` + Server serverConfig `toml:"server"` + Cgroup cgroupConfig `toml:"cgroup"` + ZFS zfsConfig `toml:"zfs"` + BtrfsSnapshot btrfsSnapshotConfig `toml:"btrfs_snapshot"` + Docker dockerConfig `toml:"docker"` + Include includeConfig `toml:"include"` + Mirrors []mirrorConfig `toml:"mirrors"` } type globalConfig struct { @@ -96,6 +97,11 @@ type zfsConfig struct { Zpool string `toml:"zpool"` } +type btrfsSnapshotConfig struct { + Enable bool `toml:"enable"` + SnapshotPath string `toml:"snapshot_path"` +} + type includeConfig struct { IncludeMirrors string `toml:"include_mirrors"` } @@ -136,6 +142,8 @@ type mirrorConfig struct { DockerImage string `toml:"docker_image"` DockerVolumes []string `toml:"docker_volumes"` DockerOptions []string `toml:"docker_options"` + + SnapshotPath string `toml:"snapshot_path"` } // LoadConfig loads configuration diff --git a/worker/provider.go b/worker/provider.go index 7ea6b60..1e05ee6 100644 --- a/worker/provider.go +++ b/worker/provider.go @@ -180,6 +180,11 @@ func newMirrorProvider(mirror mirrorConfig, cfg *Config) mirrorProvider { provider.AddHook(newZfsHook(provider, cfg.ZFS.Zpool)) } + // Add Btrfs Snapshot Hook + if cfg.BtrfsSnapshot.Enable { + provider.AddHook(newBtrfsSnapshotHook(provider, cfg.BtrfsSnapshot.SnapshotPath, mirror)) + } + // Add Docker Hook if cfg.Docker.Enable && len(mirror.DockerImage) > 0 { provider.AddHook(newDockerHook(provider, cfg.Docker, mirror))