feat(v2): add empty visualization type and cleanup marshalling

v2/cell.go

@@ -42,6 +42,7 @@ type CellContentsUpdate struct {
 
 // CellFilter represents a set of filter that restrict the returned results.
 type CellFilter struct {
+	ID *ID
 }
 
 // Cell holds positional and visual information for a cell.
@@ -59,6 +60,11 @@ type Visualization interface {
 	Visualization()
 }
 
+// EmptyVisualization is visuaization that has no values
+type EmptyVisualization struct{}
+
+func (v EmptyVisualization) Visualization() {}
+
 func UnmarshalVisualizationJSON(b []byte) (Visualization, error) {
 	var v struct {
 		B json.RawMessage `json:"visualization"`
@@ -68,6 +74,11 @@ func UnmarshalVisualizationJSON(b []byte) (Visualization, error) {
 		return nil, err
 	}
 
+	if len(v.B) == 0 {
+		// Then there wasn't any visualizaiton field, so there's no need unmarshal it
+		return EmptyVisualization{}, nil
+	}
+
 	var t struct {
 		Type string `json:"type"`
 	}
@@ -84,6 +95,12 @@ func UnmarshalVisualizationJSON(b []byte) (Visualization, error) {
 			return nil, err
 		}
 		vis = qv
+	case "empty":
+		var ev EmptyVisualization
+		if err := json.Unmarshal(v.B, &ev); err != nil {
+			return nil, err
+		}
+		vis = ev
 	default:
 		return nil, fmt.Errorf("unknown type %v", t.Type)
 	}
@@ -102,6 +119,14 @@ func MarshalVisualizationJSON(v Visualization) ([]byte, error) {
 			Type:            "chronograf-v1",
 			V1Visualization: vis,
 		}
+	case EmptyVisualization:
+		s = struct {
+			Type string `json:"type"`
+			EmptyVisualization
+		}{
+			Type:               "empty",
+			EmptyVisualization: vis,
+		}
 	default:
 		return nil, fmt.Errorf("unsupported type")
 	}
@@ -141,19 +166,6 @@ func (u *CellUpdate) UnmarshalJSON(b []byte) error {
 		return err
 	}
 
-	var vs struct {
-		B json.RawMessage `json:"visualization"`
-	}
-
-	if err := json.Unmarshal(b, &vs); err != nil {
-		return err
-	}
-
-	if len(vs.B) == 0 {
-		// Then there wasn't any visualizaiton field, so there's no need to update it
-		return nil
-	}
-
 	v, err := UnmarshalVisualizationJSON(b)
 	if err != nil {
 		return err

v2/cell_test.go

@@ -6,7 +6,6 @@ import (
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/influxdata/chronograf/v2"
-	"github.com/influxdata/platform"
 )
 
 func TestCell_MarshalJSON(t *testing.T) {
@@ -25,7 +24,7 @@ func TestCell_MarshalJSON(t *testing.T) {
 			args: args{
 				cell: chronograf.Cell{
 					CellContents: chronograf.CellContents{
-						ID:   platform.ID("0"), // This ends up being id 30 encoded
+						ID:   chronograf.ID("0"),
 						Name: "hello",
 					},
 					Visualization: chronograf.V1Visualization{
@@ -36,7 +35,7 @@ func TestCell_MarshalJSON(t *testing.T) {
 			wants: wants{
 				json: `
 {
-  "id": "30",
+  "id": "0",
   "name": "hello",
   "visualization": {
     "type": "chronograf-v1",