feat: add full snapshot downloads and safe manual restore

internal/api/config.go

@@ -23,6 +23,14 @@ var backupIDPattern = regexp.MustCompile("^[a-f0-9]{32}$")
 var configBodySlots = make(chan struct{}, 4)
 
 func (a *API) config(w http.ResponseWriter, r *http.Request, i store.Instance, action string) {
+	if action == "snapshots" && r.Method == http.MethodGet && r.URL.Query().Get("download") != "" {
+		a.snapshotDownload(w, r, i)
+		return
+	}
+	if action == "snapshots" && r.Method == http.MethodPost {
+		a.snapshotRestore(w, r, i)
+		return
+	}
 	if action == "snapshots" || (action == "backups" && r.Method == http.MethodDelete) {
 		a.backupManagement(w, r, i, action)
 		return
@@ -472,6 +480,15 @@ func (a *API) config(w http.ResponseWriter, r *http.Request, i store.Instance, a
 			return
 		}
 		snapshot := "pre-restore-" + store.ID()
+		failed := "failed-restore-" + store.ID()
+		if e = a.recordSnapshot(i, snapshot, i.Version, i.ImageID); e != nil {
+			fail(w, 500, "snapshot metadata unavailable")
+			return
+		}
+		if e = a.recordSnapshot(i, failed, i.Version, i.ImageID); e != nil {
+			fail(w, 500, "snapshot metadata unavailable")
+			return
+		}
 		if _, e = a.quotaSnapshot(i.UID, parent, restoredBytes); e != nil {
 			fail(w, 413, "quota exceeded or snapshot size unavailable")
 			return
@@ -540,7 +557,6 @@ func (a *API) config(w http.ResponseWriter, r *http.Request, i store.Instance, a
 				fail(w, 500, "restore rollback requires runtime stop")
 				return
 			}
-			failed := "failed-restore-" + store.ID()
 			if parent.Rename("home", failed) != nil || parent.Rename(snapshot, "home") != nil || upgradeSync(parent) != nil {
 				a.s.SetInstance(i.ID, "error")
 				fail(w, 500, "restore rollback requires administrator recovery")