SSE: Change math expression to accept any value convertible to float (#34996)

* SSE: Change math expression to accept any scalar value

* Apply suggestions from code review

* Update test

* Remove TODO

go.mod

@@ -52,7 +52,7 @@ require (
 	github.com/gosimple/slug v1.9.0
 	github.com/grafana/grafana-aws-sdk v0.4.0
 	github.com/grafana/grafana-live-sdk v0.0.6
-	github.com/grafana/grafana-plugin-sdk-go v0.102.0
+	github.com/grafana/grafana-plugin-sdk-go v0.104.0
 	github.com/grafana/loki v1.6.2-0.20210520072447-15d417efe103
 	github.com/grpc-ecosystem/go-grpc-middleware v1.3.0
 	github.com/hashicorp/go-hclog v0.16.0

go.sum

@@ -922,6 +922,8 @@ github.com/grafana/grafana-plugin-sdk-go v0.79.0/go.mod h1:NvxLzGkVhnoBKwzkst6CF
 github.com/grafana/grafana-plugin-sdk-go v0.91.0/go.mod h1:Ot3k7nY7P6DXmUsDgKvNB7oG1v7PRyTdmnYVoS554bU=
 github.com/grafana/grafana-plugin-sdk-go v0.102.0 h1:Pknh7mlOaJvdhPgKHxcimDOSd9h29eSpA34W0/sOF6c=
 github.com/grafana/grafana-plugin-sdk-go v0.102.0/go.mod h1:D7x3ah+1d4phNXpbnOaxa/osSaZlwh9/ZUnGGzegRbk=
+github.com/grafana/grafana-plugin-sdk-go v0.104.0 h1:Ij2tPdEasSjCb2MxHaaiylyW4RLVZYyWpApzN/mlTxo=
+github.com/grafana/grafana-plugin-sdk-go v0.104.0/go.mod h1:D7x3ah+1d4phNXpbnOaxa/osSaZlwh9/ZUnGGzegRbk=
 github.com/grafana/loki v1.6.2-0.20210520072447-15d417efe103 h1:qCmofFVwQR9QnsinstVqI1NPLMVl33jNCnOCXEAVn6E=
 github.com/grafana/loki v1.6.2-0.20210520072447-15d417efe103/go.mod h1:GHIsn+EohCChsdu5YouNZewqLeV9L2FNw4DEJU3P9qE=
 github.com/gregjones/httpcache v0.0.0-20180305231024-9cad4c3443a7/go.mod h1:FecbI9+v66THATjSRHfNgh1IVFe/9kFxbXtjV0ctIMA=

pkg/expr/mathexp/exp_test.go

@@ -30,10 +30,27 @@ func makeNumber(name string, labels data.Labels, f *float64) Number {
 	return newNumber
 }
 
+func unixTimePointer(sec, nsec int64) *time.Time {
+	t := time.Unix(sec, nsec)
+	return &t
+}
+
 func float64Pointer(f float64) *float64 {
 	return &f
 }
 
+func strPointer(s string) *string {
+	return &s
+}
+
+func int64Pointer(i int64) *int64 {
+	return &i
+}
+
+func boolPointer(b bool) *bool {
+	return &b
+}
+
 var aSeries = Vars{
 	"A": Results{
 		[]Value{

pkg/expr/mathexp/type_series.go

@@ -18,8 +18,6 @@ const seriesTypeValIdx = 1
 // Series has a time.Time and a *float64 fields.
 type Series struct {
 	Frame *data.Frame
-	// TODO:
-	// - Value can be different number types
 }
 
 // SeriesFromFrame validates that the dataframe can be considered a Series type
@@ -49,6 +47,26 @@ FIELDS:
 			valueNullable = true
 			valueIdx = i
 		default:
+			// Handle default case
+			// try to convert to *float64
+			var convertedField *data.Field
+			for j := 0; j < field.Len(); j++ {
+				ff, err := field.NullableFloatAt(j)
+				if err != nil {
+					break
+				}
+				if convertedField == nil { // initialise field
+					convertedField = data.NewFieldFromFieldType(data.FieldTypeNullableFloat64, field.Len())
+					convertedField.Name = field.Name
+					convertedField.Labels = field.Labels
+				}
+				convertedField.Set(j, ff)
+			}
+			if convertedField != nil {
+				frame.Fields[i] = convertedField
+				valueNullable = true
+				valueIdx = i
+			}
 			if valueIdx != -1 && timeIdx != -1 {
 				break FIELDS
 			}
@@ -65,7 +83,7 @@ FIELDS:
 	if timeNullable { // make time not nullable if it is in the input
 		timeSlice := make([]time.Time, 0, frame.Fields[timeIdx].Len())
 		for rowIdx := 0; rowIdx < frame.Fields[timeIdx].Len(); rowIdx++ {
-			val, ok := frame.At(0, rowIdx).(*time.Time)
+			val, ok := frame.At(timeIdx, rowIdx).(*time.Time)
 			if !ok {
 				return s, fmt.Errorf("unexpected time type, expected *time.Time but got %T", val)
 			}

pkg/expr/mathexp/types_test.go

@@ -136,6 +136,132 @@ func TestSeriesFromFrame(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "[]*int, []*time frame should convert",
+			frame: &data.Frame{
+				Name: "test",
+				Fields: []*data.Field{
+					data.NewField("time", nil, []*time.Time{unixTimePointer(5, 0)}),
+					data.NewField("value", nil, []*int64{int64Pointer(5)}),
+				},
+			},
+			errIs: assert.NoError,
+			Is:    assert.Equal,
+			Series: Series{
+				Frame: &data.Frame{
+					Name: "test",
+					Fields: []*data.Field{
+						data.NewField("time", nil, []time.Time{time.Unix(5, 0)}),
+						data.NewField("value", nil, []*float64{float64Pointer(5)}),
+					},
+				},
+			},
+		},
+		{
+			name: "[]int, []*time frame should convert",
+			frame: &data.Frame{
+				Name: "test",
+				Fields: []*data.Field{
+					data.NewField("time", nil, []*time.Time{unixTimePointer(5, 0)}),
+					data.NewField("value", nil, []int64{5}),
+				},
+			},
+			errIs: assert.NoError,
+			Is:    assert.Equal,
+			Series: Series{
+				Frame: &data.Frame{
+					Name: "test",
+					Fields: []*data.Field{
+						data.NewField("time", nil, []time.Time{time.Unix(5, 0)}),
+						data.NewField("value", nil, []*float64{float64Pointer(5)}),
+					},
+				},
+			},
+		},
+		{
+			name: "[]string, []*time frame should convert",
+			frame: &data.Frame{
+				Name: "test",
+				Fields: []*data.Field{
+					data.NewField("time", nil, []*time.Time{unixTimePointer(5, 0)}),
+					data.NewField("value", nil, []string{"5"}),
+				},
+			},
+			errIs: assert.NoError,
+			Is:    assert.Equal,
+			Series: Series{
+				Frame: &data.Frame{
+					Name: "test",
+					Fields: []*data.Field{
+						data.NewField("time", nil, []time.Time{time.Unix(5, 0)}),
+						data.NewField("value", nil, []*float64{float64Pointer(5)}),
+					},
+				},
+			},
+		},
+		{
+			name: "[]*string, []*time frame should convert",
+			frame: &data.Frame{
+				Name: "test",
+				Fields: []*data.Field{
+					data.NewField("time", nil, []*time.Time{unixTimePointer(5, 0)}),
+					data.NewField("value", nil, []*string{strPointer("5")}),
+				},
+			},
+			errIs: assert.NoError,
+			Is:    assert.Equal,
+			Series: Series{
+				Frame: &data.Frame{
+					Name: "test",
+					Fields: []*data.Field{
+						data.NewField("time", nil, []time.Time{time.Unix(5, 0)}),
+						data.NewField("value", nil, []*float64{float64Pointer(5)}),
+					},
+				},
+			},
+		},
+		{
+			name: "[]bool, []*time frame should convert",
+			frame: &data.Frame{
+				Name: "test",
+				Fields: []*data.Field{
+					data.NewField("time", nil, []*time.Time{unixTimePointer(5, 0)}),
+					data.NewField("value", nil, []bool{true}),
+				},
+			},
+			errIs: assert.NoError,
+			Is:    assert.Equal,
+			Series: Series{
+				Frame: &data.Frame{
+					Name: "test",
+					Fields: []*data.Field{
+						data.NewField("time", nil, []time.Time{time.Unix(5, 0)}),
+						data.NewField("value", nil, []*float64{float64Pointer(1)}),
+					},
+				},
+			},
+		},
+		{
+			name: "[]*bool, []*time frame should convert",
+			frame: &data.Frame{
+				Name: "test",
+				Fields: []*data.Field{
+					data.NewField("time", nil, []*time.Time{unixTimePointer(5, 0)}),
+					data.NewField("value", nil, []*bool{boolPointer(true)}),
+				},
+			},
+			errIs: assert.NoError,
+			Is:    assert.Equal,
+			Series: Series{
+				Frame: &data.Frame{
+					Name: "test",
+					Fields: []*data.Field{
+						data.NewField("time", nil, []time.Time{time.Unix(5, 0)}),
+						data.NewField("value", nil, []*float64{float64Pointer(1)}),
+					},
+				},
+			},
+		},
 		{
 			name: "[]*time, []*time frame should error",
 			frame: &data.Frame{