Rename backups => snapshot

env/snapshot.go

@@ -6,12 +6,62 @@ import (
 	"os"
 	"path/filepath"
 	"sync"
+	"time"
 
 	"github.com/FAU-CDI/wisski-distillery/internal/fsx"
 	"github.com/FAU-CDI/wisski-distillery/internal/logging"
+	"github.com/FAU-CDI/wisski-distillery/internal/password"
 	"github.com/tkw1536/goprogram/stream"
 )
 
+// SnapshotsDir returns the path that contains all snapshot related data.
+func (dis Distillery) SnapshotsDir() string {
+	return filepath.Join(dis.Config.DeployRoot, "snapshots")
+}
+
+// SnapshotsStagingPath returns the path to the directory containing a temporary staging area for snapshots.
+// Use NewSnapshotStagingDir to generate a new staging area.
+func (dis Distillery) SnapshotsStagingPath() string {
+	return filepath.Join(dis.SnapshotsDir(), "staging")
+}
+
+// SnapshotsArchivePath returns the path to the directory containing all exported archives.
+// Use NewSnapshotArchivePath to generate a path to a new archive in this directory.
+func (dis Distillery) SnapshotsArchivePath() string {
+	return filepath.Join(dis.SnapshotsDir(), "archives")
+}
+
+// NewSnapshotArchivePath returns the path to a new archive with the provided prefix.
+// The path is guaranteed to not exist.
+func (dis Distillery) NewSnapshotArchivePath(prefix string) (path string) {
+	// TODO: Consider moving these into a subdirectory with the provided prefix.
+	for path == "" || fsx.Exists(path) {
+		name := dis.newSnapshotName(prefix) + ".tar.gz"
+		path = filepath.Join(dis.SnapshotsArchivePath(), name)
+	}
+	return
+}
+
+// newSnapshot name returns a new basename for a snapshot with the provided prefix.
+// The name is guaranteed to be unique within this process.
+func (Distillery) newSnapshotName(prefix string) string {
+	suffix, _ := password.Password(64) // silently ignore any errors!
+	return fmt.Sprintf("%s-%d-%s", prefix, time.Now().Unix(), suffix)
+}
+
+// NewSnapshotStagingDir returns the path to a new snapshot directory.
+// The directory is guaranteed to have been freshly created.
+func (dis Distillery) NewSnapshotStagingDir(prefix string) (path string, err error) {
+	for path == "" || os.IsExist(err) {
+		path = filepath.Join(dis.SnapshotsStagingPath(), dis.newSnapshotName(prefix))
+		err = os.Mkdir(path, os.ModeDir)
+	}
+	if err != nil {
+		path = ""
+	}
+	return
+}
+
 type SnapshotReport struct {
 	Keepalive bool        // was the instance alive while running the snapshot?
 	Panic     interface{} // was there a panic?