Validate snapshot ID in SnapshotInfo (#1009)

* Validate snapshot ID in SnapshotInfo

Signed-off-by: Prasad Ghangal <prasad.ghangal@gmail.com>

* Add new Validate method

Signed-off-by: Prasad Ghangal <prasad.ghangal@gmail.com>

* Refactor snapshot unmarshal method

Signed-off-by: Prasad Ghangal <prasad.ghangal@gmail.com>

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

pkg/kopia/stream.go

@@ -50,6 +50,17 @@ type SnapshotInfo struct {
 	PhysicalSize int64 `json:"physicalSize"`
 }
 
+// Validate validates SnapshotInfo field values
+func (si *SnapshotInfo) Validate() error {
+	if si == nil {
+		return errors.New("kopia snapshotInfo cannot be nil")
+	}
+	if si.ID == "" {
+		return errors.New("kopia snapshot ID cannot be empty")
+	}
+	return nil
+}
+
 // Write creates a kopia snapshot from the given reader
 // A virtual directory tree rooted at filepath.Dir(path) is created with
 // a kopia streaming file with filepath.Base(path) as name

pkg/kopia/utils.go

@@ -194,6 +194,9 @@ func GetDataStoreGeneralMetadataCacheSize(opt map[string]int) int {
 
 // MarshalKopiaSnapshot encodes kopia SnapshotInfo struct into a string
 func MarshalKopiaSnapshot(snapInfo *SnapshotInfo) (string, error) {
+	if err := snapInfo.Validate(); err != nil {
+		return "", err
+	}
 	snap, err := json.Marshal(snapInfo)
 	if err != nil {
 		return "", errors.Wrap(err, "failed to marshal kopia snapshot information")
@@ -205,6 +208,8 @@ func MarshalKopiaSnapshot(snapInfo *SnapshotInfo) (string, error) {
 // UnmarshalKopiaSnapshot decodes a kopia snapshot JSON string into SnapshotInfo struct
 func UnmarshalKopiaSnapshot(snapInfoJSON string) (SnapshotInfo, error) {
 	snap := SnapshotInfo{}
-	err := json.Unmarshal([]byte(snapInfoJSON), &snap)
-	return snap, errors.Wrap(err, "failed to unmarshal kopia snapshot information")
+	if err := json.Unmarshal([]byte(snapInfoJSON), &snap); err != nil {
+		return snap, errors.Wrap(err, "failed to unmarshal kopia snapshot information")
+	}
+	return snap, snap.Validate()
 }