backup(longhorn): create snapshot before snapshot backup

internal/longhorn/client.go

@@ -85,11 +85,25 @@ type snapshotInput struct {
 	BackupMode string            `json:"backupMode,omitempty"`
 }
 
+type snapshotCreateInput struct {
+	Name   string            `json:"name,omitempty"`
+	Labels map[string]string `json:"labels,omitempty"`
+}
+
 type pvcCreateInput struct {
 	Namespace string `json:"namespace"`
 	PVCName   string `json:"pvcName"`
 }
 
+func (c *Client) CreateSnapshot(ctx context.Context, volume, name string, labels map[string]string) error {
+	path := fmt.Sprintf("%s/v1/volumes/%s?action=snapshotCreate", c.baseURL, url.PathEscape(volume))
+	input := snapshotCreateInput{
+		Name:   name,
+		Labels: labels,
+	}
+	return c.doJSON(ctx, http.MethodPost, path, input, nil)
+}
+
 func (c *Client) SnapshotBackup(ctx context.Context, volume, name string, labels map[string]string, backupMode string) (*Volume, error) {
 	path := fmt.Sprintf("%s/v1/volumes/%s?action=snapshotBackup", c.baseURL, url.PathEscape(volume))
 	input := snapshotInput{

internal/server/server.go

@@ -35,6 +35,7 @@ type kubeClient interface {
 }
 
 type longhornClient interface {
+	CreateSnapshot(ctx context.Context, volume, name string, labels map[string]string) error
 	SnapshotBackup(ctx context.Context, volume, name string, labels map[string]string, backupMode string) (*longhorn.Volume, error)
 	GetVolume(ctx context.Context, volume string) (*longhorn.Volume, error)
 	CreateVolumeFromBackup(ctx context.Context, name, size string, replicas int, backupURL string) (*longhorn.Volume, error)
@@ -620,6 +621,9 @@ func (s *Server) executeBackup(ctx context.Context, req api.BackupRequest, reque
 			"soteria.bstein.dev/pvc":          req.PVC,
 			"soteria.bstein.dev/requested-by": requester,
 		}
+		if err := s.longhorn.CreateSnapshot(ctx, volumeName, backupID, labels); err != nil {
+			return api.BackupResponse{}, "backend_error", err
+		}
 		if _, err := s.longhorn.SnapshotBackup(ctx, volumeName, backupID, labels, s.cfg.LonghornBackupMode); err != nil {
 			return api.BackupResponse{}, "backend_error", err
 		}

internal/server/server_test.go

@@ -68,10 +68,18 @@ func (f *fakeKubeClient) SaveSecretData(_ context.Context, _, _, key string, val
 }
 
 type fakeLonghornClient struct {
-	backups []longhorn.Backup
+	backups            []longhorn.Backup
+	createSnapshotName string
+	snapshotBackupName string
+}
+
+func (f *fakeLonghornClient) CreateSnapshot(_ context.Context, volume, name string, labels map[string]string) error {
+	f.createSnapshotName = name
+	return nil
 }
 
 func (f *fakeLonghornClient) SnapshotBackup(_ context.Context, volume, name string, labels map[string]string, backupMode string) (*longhorn.Volume, error) {
+	f.snapshotBackupName = name
 	return &longhorn.Volume{Name: volume}, nil
 }
 
@@ -222,6 +230,38 @@ func TestRestoreRejectsSameSourceAndTarget(t *testing.T) {
 	}
 }
 
+func TestBackupCreatesSnapshotBeforeBackup(t *testing.T) {
+	lh := &fakeLonghornClient{}
+	srv := &Server{
+		cfg:      &config.Config{AuthRequired: false, BackupDriver: "longhorn", LonghornBackupMode: "incremental"},
+		client:   &fakeKubeClient{},
+		longhorn: lh,
+		metrics:  newTelemetry(),
+	}
+	srv.handler = http.HandlerFunc(srv.route)
+
+	body := `{"namespace":"apps","pvc":"data","dry_run":false}`
+	req := httptest.NewRequest(http.MethodPost, "/v1/backup", strings.NewReader(body))
+	res := httptest.NewRecorder()
+	srv.Handler().ServeHTTP(res, req)
+
+	if res.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d: %s", res.Code, res.Body.String())
+	}
+	if lh.createSnapshotName == "" {
+		t.Fatalf("expected snapshot creation call")
+	}
+	if lh.snapshotBackupName == "" {
+		t.Fatalf("expected snapshot backup call")
+	}
+	if lh.createSnapshotName != lh.snapshotBackupName {
+		t.Fatalf("expected same snapshot and backup name, got snapshot=%q backup=%q", lh.createSnapshotName, lh.snapshotBackupName)
+	}
+	if !strings.HasPrefix(lh.createSnapshotName, "soteria-backup-apps-data-") {
+		t.Fatalf("unexpected generated backup name %q", lh.createSnapshotName)
+	}
+}
+
 func TestMetricsStayPublic(t *testing.T) {
 	srv := &Server{
 		cfg:      &config.Config{AuthRequired: true, AllowedGroups: []string{"admin"}},