Enforce only "x", "y", and "y2" axes

For the forseeable future, we will only be using the "x", "y", and "y2"
axes, even though the underlying serialization can support arbitrary
axes (for the future).

This ensures that only "x", "y", and "y2" axes are present and updates
the Swagger docs to reflect that fact

chronograf.go

@@ -29,6 +29,7 @@ const (
 	ErrAlertNotFound     = Error("alert not found")
 	ErrAuthentication    = Error("user not authenticated")
 	ErrUninitialized     = Error("client uninitialized. Call Open() method")
+	ErrInvalidAxis       = Error("Unexpected axis in cell. Valid axes are 'x', 'y', and 'y2'")
 )
 
 // Error is a domain error encountered while processing chronograf requests

server/cells.go

@@ -43,9 +43,23 @@ func newCellResponses(dID chronograf.DashboardID, dcells []chronograf.DashboardC
 	return cells
 }
 
-// ValidDashboardCellRequest verifies that the dashboard cells have a query
+// ValidDashboardCellRequest verifies that the dashboard cells have a query and
+// have the correct axes specified
 func ValidDashboardCellRequest(c *chronograf.DashboardCell) error {
 	CorrectWidthHeight(c)
+	return HasCorrectAxes(c)
+}
+
+// HasCorrectAxes verifies that only permitted axes exist within a DashboardCell
+func HasCorrectAxes(c *chronograf.DashboardCell) error {
+	for axis, _ := range c.Axes {
+		switch axis {
+		case "x", "y", "y2":
+			// no-op
+		default:
+			return chronograf.ErrInvalidAxis
+		}
+	}
 	return nil
 }
 

server/cells_test.go

@@ -0,0 +1,60 @@
+package server_test
+
+import (
+	"testing"
+
+	"github.com/influxdata/chronograf"
+	"github.com/influxdata/chronograf/server"
+)
+
+func Test_Cells_CorrectAxis(t *testing.T) {
+	t.Parallel()
+
+	axisTests := []struct {
+		name       string
+		cell       *chronograf.DashboardCell
+		shouldFail bool
+	}{
+		{
+			"correct axes",
+			&chronograf.DashboardCell{
+				Axes: map[string]chronograf.Axis{
+					"x": chronograf.Axis{
+						Bounds: [2]int64{0, 100},
+					},
+					"y": chronograf.Axis{
+						Bounds: [2]int64{0, 100},
+					},
+					"y2": chronograf.Axis{
+						Bounds: [2]int64{0, 100},
+					},
+				},
+			},
+			false,
+		},
+		{
+			"invalid axes present",
+			&chronograf.DashboardCell{
+				Axes: map[string]chronograf.Axis{
+					"axis of evil": chronograf.Axis{
+						Bounds: [2]int64{666, 666},
+					},
+					"axis of awesome": chronograf.Axis{
+						Bounds: [2]int64{1337, 31337},
+					},
+				},
+			},
+			true,
+		},
+	}
+
+	for _, test := range axisTests {
+		t.Run(test.name, func(tt *testing.T) {
+			if err := server.HasCorrectAxes(test.cell); err != nil && !test.shouldFail {
+				t.Errorf("%q: Unexpected error: err: %s", test.name, err)
+			} else if err == nil && test.shouldFail {
+				t.Errorf("%q: Expected error and received none", test.name)
+			}
+		})
+	}
+}

server/dashboards_test.go

@@ -4,6 +4,7 @@ import (
 	"reflect"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
 	"github.com/influxdata/chronograf"
 )
 
@@ -219,6 +220,14 @@ func Test_newDashboardResponse(t *testing.T) {
 								Command: "SELECT donors from hill_valley_preservation_society where time > '1985-10-25 08:00:00'",
 							},
 						},
+						Axes: map[string]chronograf.Axis{
+							"x": chronograf.Axis{
+								Bounds: [2]int64{0, 100},
+							},
+							"y": chronograf.Axis{
+								Bounds: [2]int64{2, 95},
+							},
+						},
 					},
 					{
 						ID: "b",
@@ -257,6 +266,14 @@ func Test_newDashboardResponse(t *testing.T) {
 									},
 								},
 							},
+							Axes: map[string]chronograf.Axis{
+								"x": chronograf.Axis{
+									Bounds: [2]int64{0, 100},
+								},
+								"y": chronograf.Axis{
+									Bounds: [2]int64{2, 95},
+								},
+							},
 						},
 					},
 					dashboardCellResponse{
@@ -301,8 +318,8 @@ func Test_newDashboardResponse(t *testing.T) {
 		},
 	}
 	for _, tt := range tests {
-		if got := newDashboardResponse(tt.d); !reflect.DeepEqual(got, tt.want) {
-			t.Errorf("%q. newDashboardResponse() = \n%#v\n\n, want\n\n%#v", tt.name, got, tt.want)
+		if got := newDashboardResponse(tt.d); !cmp.Equal(got, tt.want) {
+			t.Errorf("%q. newDashboardResponse() = diff:\n%s", tt.name, cmp.Diff(got, tt.want))
 		}
 	}
 }

server/swagger.json

@@ -3718,8 +3718,16 @@
               "axes": {
                 "description": "The viewport for a cell's visualizations",
                 "type": "object",
-                "additionalProperties": {
+                "properties": {
+                  "x": {
                     "$ref": "#/definitions/DashboardRange"
+                  },
+                  "y": {
+                    "$ref": "#/definitions/DashboardRange"
+                  },
+                  "y2": {
+                    "$ref": "#/definitions/DashboardRange"
+                  }
                 }
               },
               "type": {
@@ -3814,7 +3822,7 @@
           "description": "The extents of an axis in the form [lower, upper]. Clients determine whether bounds are to be inclusive or exclusive of their limits",
           "items": {
             "type": "integer",
-            "format": "int32"
+            "format": "int64"
           }
         }
       }