SSE/Alerting: Support prom instant vector responses (#44865)

* SSE/Alerting: (Draft) Support prom instant vector responses
fixes #35663
* reduce\classic expressions to handle mathexp.Number
* use Notice for warning

Co-authored-by: Yuriy Tseretyan <yuriy.tseretyan@grafana.com>

pkg/expr/classic/classic.go

@@ -7,6 +7,7 @@ import (
 	"strconv"
 
 	"github.com/grafana/grafana-plugin-sdk-go/data"
+
 	"github.com/grafana/grafana/pkg/expr/mathexp"
 )
 
@@ -99,13 +100,21 @@ func (ccc *ConditionsCmd) Execute(ctx context.Context, vars mathexp.Vars) (mathe
 		nilReducedCount := 0
 		firingCount := 0
 		for _, val := range querySeriesSet.Values {
-			series, ok := val.(mathexp.Series)
-			if !ok {
+			var reducedNum mathexp.Number
+			var name string
+			switch v := val.(type) {
+			case mathexp.Series:
+				reducedNum = c.Reducer.Reduce(v)
+				name = v.GetName()
+			case mathexp.Number:
+				reducedNum = v
+				if len(v.Frame.Fields) > 0 {
+					name = v.Frame.Fields[0].Name
+				}
+			default:
 				return newRes, fmt.Errorf("can only reduce type series, got type %v", val.Type())
 			}
 
-			reducedNum := c.Reducer.Reduce(series)
-
 			// TODO handle error / no data signals
 			thisCondNoDataFound := reducedNum.GetFloat64Value() == nil
 
@@ -118,7 +127,7 @@ func (ccc *ConditionsCmd) Execute(ctx context.Context, vars mathexp.Vars) (mathe
 			if evalRes {
 				match := EvalMatch{
 					Value:  reducedNum.GetFloat64Value(),
-					Metric: series.GetName(),
+					Metric: name,
 				}
 				if reducedNum.GetLabels() != nil {
 					match.Labels = reducedNum.GetLabels().Copy()

pkg/expr/classic/classic_test.go

@@ -6,9 +6,10 @@ import (
 	"testing"
 
 	"github.com/grafana/grafana-plugin-sdk-go/data"
-	"github.com/grafana/grafana/pkg/expr/mathexp"
 	"github.com/stretchr/testify/require"
 	ptr "github.com/xorcare/pointer"
+
+	"github.com/grafana/grafana/pkg/expr/mathexp"
 )
 
 func TestUnmarshalConditionCMD(t *testing.T) {
@@ -346,6 +347,37 @@ func TestConditionsCmdExecute(t *testing.T) {
 				return v
 			},
 		},
+		{
+			name: "should accept numbers",
+			vars: mathexp.Vars{
+				"A": mathexp.Results{
+					Values: []mathexp.Value{
+						valBasedNumber(ptr.Float64(5)),
+						valBasedNumber(ptr.Float64(10)),
+						valBasedNumber(ptr.Float64(15)),
+					},
+				},
+			},
+			conditionsCmd: &ConditionsCmd{
+				Conditions: []condition{
+					{
+						QueryRefID: "A",
+						Reducer:    classicReducer("avg"),
+						Operator:   "and",
+						Evaluator:  &thresholdEvaluator{"gt", 1},
+					},
+				},
+			},
+			resultNumber: func() mathexp.Number {
+				v := valBasedNumber(ptr.Float64(1))
+				v.SetMeta([]EvalMatch{
+					{Value: ptr.Float64(5)},
+					{Value: ptr.Float64(10)},
+					{Value: ptr.Float64(15)},
+				})
+				return v
+			},
+		},
 	}
 
 	for _, tt := range tests {

pkg/expr/commands.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/grafana/grafana-plugin-sdk-go/backend/gtime"
+	"github.com/grafana/grafana-plugin-sdk-go/data"
 
 	"github.com/grafana/grafana/pkg/expr/mathexp"
 )
@@ -152,18 +153,27 @@ func (gr *ReduceCommand) NeedsVars() []string {
 
 // Execute runs the command and returns the results or an error if the command
 // failed to execute.
-func (gr *ReduceCommand) Execute(ctx context.Context, vars mathexp.Vars) (mathexp.Results, error) {
+func (gr *ReduceCommand) Execute(_ context.Context, vars mathexp.Vars) (mathexp.Results, error) {
 	newRes := mathexp.Results{}
 	for _, val := range vars[gr.VarToReduce].Values {
-		series, ok := val.(mathexp.Series)
-		if !ok {
+		switch v := val.(type) {
+		case mathexp.Series:
+			num, err := v.Reduce(gr.refID, gr.Reducer, gr.seriesMapper)
+			if err != nil {
+				return newRes, err
+			}
+			newRes.Values = append(newRes.Values, num)
+		case mathexp.Number: // if incoming vars is just a number, any reduce op is just a noop, add it as it is
+			copyV := mathexp.NewNumber(gr.refID, v.GetLabels())
+			copyV.SetValue(v.GetFloat64Value())
+			copyV.AddNotice(data.Notice{
+				Severity: data.NoticeSeverityWarning,
+				Text:     fmt.Sprintf("Reduce operation is not needed. Input query or expression %s is already reduced data.", gr.VarToReduce),
+			})
+			newRes.Values = append(newRes.Values, copyV)
+		default:
 			return newRes, fmt.Errorf("can only reduce type series, got type %v", val.Type())
 		}
-		num, err := series.Reduce(gr.refID, gr.Reducer, gr.seriesMapper)
-		if err != nil {
-			return newRes, err
-		}
-		newRes.Values = append(newRes.Values, num)
 	}
 	return newRes, nil
 }

pkg/expr/commands_test.go

@@ -1,13 +1,18 @@
 package expr
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
+	"math/rand"
 	"testing"
 
+	"github.com/grafana/grafana-plugin-sdk-go/data"
 	"github.com/stretchr/testify/require"
+	ptr "github.com/xorcare/pointer"
 
 	"github.com/grafana/grafana/pkg/expr/mathexp"
+	"github.com/grafana/grafana/pkg/util"
 )
 
 func Test_UnmarshalReduceCommand_Settings(t *testing.T) {
@@ -89,3 +94,51 @@ func Test_UnmarshalReduceCommand_Settings(t *testing.T) {
 		})
 	}
 }
+
+func TestReduceExecute(t *testing.T) {
+	varToReduce := util.GenerateShortUID()
+	cmd, err := NewReduceCommand(util.GenerateShortUID(), randomReduceFunc(), varToReduce, nil)
+	require.NoError(t, err)
+
+	t.Run("should noop if Number", func(t *testing.T) {
+		var numbers mathexp.Values = []mathexp.Value{
+			mathexp.GenerateNumber(ptr.Float64(rand.Float64())),
+			mathexp.GenerateNumber(ptr.Float64(rand.Float64())),
+			mathexp.GenerateNumber(ptr.Float64(rand.Float64())),
+		}
+
+		vars := map[string]mathexp.Results{
+			varToReduce: {
+				Values: numbers,
+			},
+		}
+
+		execute, err := cmd.Execute(context.Background(), vars)
+		require.NoError(t, err)
+
+		require.Len(t, execute.Values, len(numbers))
+		for i, value := range execute.Values {
+			expected := numbers[i]
+			require.Equal(t, expected.Type(), value.Type())
+			require.Equal(t, expected.GetLabels(), value.GetLabels())
+
+			expectedValue := expected.Value().(*mathexp.Number).GetFloat64Value()
+			actualValue := value.Value().(*mathexp.Number).GetFloat64Value()
+			require.Equal(t, expectedValue, actualValue)
+		}
+
+		t.Run("should add warn notices to every frame", func(t *testing.T) {
+			frames := execute.Values.AsDataFrames("test")
+			for _, frame := range frames {
+				require.Len(t, frame.Meta.Notices, 1)
+				notice := frame.Meta.Notices[0]
+				require.Equal(t, data.NoticeSeverityWarning, notice.Severity)
+			}
+		})
+	})
+}
+
+func randomReduceFunc() string {
+	res := mathexp.GetSupportedReduceFuncs()
+	return res[rand.Intn(len(res)-1)]
+}

pkg/expr/mathexp/reduce.go

@@ -100,6 +100,11 @@ func GetReduceFunc(rFunc string) (ReducerFunc, error) {
 	}
 }
 
+// GetSupportedReduceFuncs returns collection of supported function names
+func GetSupportedReduceFuncs() []string {
+	return []string{"sum", "mean", "min", "max", "count", "last"}
+}
+
 // Reduce turns the Series into a Number based on the given reduction function
 // if ReduceMapper is defined it applies it to the provided series and performs reduction of the resulting series.
 // Otherwise, the reduction operation is done against the original series.

pkg/expr/mathexp/testing.go

@@ -0,0 +1,18 @@
+package mathexp
+
+import (
+	"math/rand"
+
+	"github.com/grafana/grafana/pkg/util"
+)
+
+func GenerateNumber(value *float64) Number {
+	size := rand.Intn(5)
+	labels := make(map[string]string, size)
+	for i := 0; i < size; i++ {
+		labels[util.GenerateShortUID()] = util.GenerateShortUID()
+	}
+	result := NewNumber(util.GenerateShortUID(), labels)
+	result.SetValue(value)
+	return result
+}

pkg/expr/mathexp/type_series.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/grafana/grafana-plugin-sdk-go/data"
+
 	"github.com/grafana/grafana/pkg/expr/mathexp/parse"
 )
 
@@ -154,7 +155,21 @@ func (s Series) GetMeta() interface{} {
 }
 
 func (s Series) SetMeta(v interface{}) {
-	s.Frame.SetMeta(&data.FrameMeta{Custom: v})
+	m := s.Frame.Meta
+	if m == nil {
+		m = &data.FrameMeta{}
+		s.Frame.SetMeta(m)
+	}
+	m.Custom = v
+}
+
+func (s Series) AddNotice(notice data.Notice) {
+	m := s.Frame.Meta
+	if m == nil {
+		m = &data.FrameMeta{}
+		s.Frame.SetMeta(m)
+	}
+	m.Notices = append(m.Notices, notice)
 }
 
 // AsDataFrame returns the underlying *data.Frame.

pkg/expr/mathexp/types.go

@@ -2,6 +2,7 @@ package mathexp
 
 import (
 	"github.com/grafana/grafana-plugin-sdk-go/data"
+
 	"github.com/grafana/grafana/pkg/expr/mathexp/parse"
 )
 
@@ -33,6 +34,7 @@ type Value interface {
 	GetMeta() interface{}
 	SetMeta(interface{})
 	AsDataFrame() *data.Frame
+	AddNotice(notice data.Notice)
 }
 
 // Scalar is the type that holds a single number constant.
@@ -55,7 +57,21 @@ func (s Scalar) GetMeta() interface{} {
 }
 
 func (s Scalar) SetMeta(v interface{}) {
-	s.Frame.SetMeta(&data.FrameMeta{Custom: v})
+	m := s.Frame.Meta
+	if m == nil {
+		m = &data.FrameMeta{}
+		s.Frame.SetMeta(m)
+	}
+	m.Custom = v
+}
+
+func (s Scalar) AddNotice(notice data.Notice) {
+	m := s.Frame.Meta
+	if m == nil {
+		m = &data.FrameMeta{}
+		s.Frame.SetMeta(m)
+	}
+	m.Notices = append(m.Notices, notice)
 }
 
 // AsDataFrame returns the underlying *data.Frame.
@@ -121,7 +137,21 @@ func (n Number) GetMeta() interface{} {
 }
 
 func (n Number) SetMeta(v interface{}) {
-	n.Frame.SetMeta(&data.FrameMeta{Custom: v})
+	m := n.Frame.Meta
+	if m == nil {
+		m = &data.FrameMeta{}
+		n.Frame.SetMeta(m)
+	}
+	m.Custom = v
+}
+
+func (n Number) AddNotice(notice data.Notice) {
+	m := n.Frame.Meta
+	if m == nil {
+		m = &data.FrameMeta{}
+		n.Frame.SetMeta(m)
+	}
+	m.Notices = append(m.Notices, notice)
 }
 
 // FloatField is a *float64 or a float64 data.Field with methods to always

pkg/expr/nodes.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
 	"github.com/grafana/grafana-plugin-sdk-go/data"
+
 	"github.com/grafana/grafana/pkg/expr/classic"
 	"github.com/grafana/grafana/pkg/expr/mathexp"
 	"github.com/grafana/grafana/pkg/infra/log"
@@ -236,6 +237,15 @@ func (dn *DSNode) Execute(ctx context.Context, vars mathexp.Vars, s *Service) (m
 			return mathexp.Results{}, QueryError{RefID: refID, Err: qr.Error}
 		}
 
+		dataSource := dn.datasource.Type
+		if isAllFrameVectors(dataSource, qr.Frames) {
+			vals, err = framesToNumbers(qr.Frames)
+			if err != nil {
+				return mathexp.Results{}, fmt.Errorf("failed to read frames as numbers: %w", err)
+			}
+			return mathexp.Results{Values: vals}, nil
+		}
+
 		if len(qr.Frames) == 1 {
 			frame := qr.Frames[0]
 			if frame.TimeSeriesSchema().Type == data.TimeSeriesTypeNot && isNumberTable(frame) {
@@ -254,7 +264,6 @@ func (dn *DSNode) Execute(ctx context.Context, vars mathexp.Vars, s *Service) (m
 			}
 		}
 
-		dataSource := dn.datasource.Type
 		for _, frame := range qr.Frames {
 			logger.Debug("expression datasource query (seriesSet)", "query", refID)
 			// Check for TimeSeriesTypeNot in InfluxDB queries. A data frame of this type will cause
@@ -278,6 +287,51 @@ func (dn *DSNode) Execute(ctx context.Context, vars mathexp.Vars, s *Service) (m
 	}, nil
 }
 
+func isAllFrameVectors(datasourceType string, frames data.Frames) bool {
+	if datasourceType != "prometheus" {
+		return false
+	}
+	allVector := false
+	for i, frame := range frames {
+		if frame.Meta != nil && frame.Meta.Custom != nil {
+			if sMap, ok := frame.Meta.Custom.(map[string]string); ok {
+				if sMap != nil {
+					if sMap["resultType"] == "vector" {
+						if i != 0 && !allVector {
+							break
+						}
+						allVector = true
+					}
+				}
+			}
+		}
+	}
+	return allVector
+}
+
+func framesToNumbers(frames data.Frames) ([]mathexp.Value, error) {
+	vals := make([]mathexp.Value, 0, len(frames))
+	for _, frame := range frames {
+		if frame == nil {
+			continue
+		}
+		if len(frame.Fields) == 2 && frame.Fields[0].Len() == 1 {
+			// Can there be zero Len Field results that are being skipped?
+			valueField := frame.Fields[1]
+			if valueField.Type().Numeric() { // should be []float64
+				val, err := valueField.FloatAt(0) // FloatAt should not err if numeric
+				if err != nil {
+					return nil, fmt.Errorf("failed to read value of frame [%v] (RefID %v) of type [%v] as float: %w", frame.Name, frame.RefID, valueField.Type(), err)
+				}
+				n := mathexp.NewNumber(frame.Name, valueField.Labels)
+				n.SetValue(&val)
+				vals = append(vals, n)
+			}
+		}
+	}
+	return vals, nil
+}
+
 func isNumberTable(frame *data.Frame) bool {
 	if frame == nil || frame.Fields == nil {
 		return false

pkg/tsdb/prometheus/buffered/time_series_query.go

@@ -587,7 +587,7 @@ func newDataFrame(name string, typ string, fields ...*data.Field) *data.Frame {
 	frame.Meta = &data.FrameMeta{
 		Type: data.FrameTypeTimeSeriesMany,
 		Custom: map[string]string{
-			"resultType": typ,
+			"resultType": typ, // Note: SSE depends on this property and map type
 		},
 	}