Add sort and sort_desc (#1104)

src/query/functions/linear/sort.go

@@ -0,0 +1,32 @@
+// Copyright (c) 2018 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package linear
+
+const (
+	// NB: Because Prometheus's sort and sort_desc only look at the last value,
+	// these functions are essentially noops in M3 as we don't support instant queries.
+
+	// SortType returns timeseries elements sorted by their values, in ascending order.
+	SortType = "sort"
+
+	// SortDescType is the same as sort, but sorts in descending order.
+	SortDescType = "sort_desc"
+)

src/query/parser/promql/parse.go

@@ -160,11 +160,15 @@ func (p *parseState) walk(node pql.Node) error {
 			}
 		}
 
-		op, err := NewFunctionExpr(n.Func.Name, argValues, stringValues)
+		op, ok, err := NewFunctionExpr(n.Func.Name, argValues, stringValues)
 		if err != nil {
 			return err
 		}
 
+		if !ok {
+			return nil
+		}
+
 		opTransform := parser.NewTransformFromOperation(op, p.transformLen())
 		if op.OpType() != scalar.TimeType {
 			p.edges = append(p.edges, parser.Edge{

src/query/parser/promql/parse_test.go

@@ -151,6 +151,30 @@ func TestLinearParses(t *testing.T) {
 	}
 }
 
+var sortTests = []struct {
+	q            string
+	expectedType string
+}{
+	{"sort(up)", linear.SortType},
+	{"sort_desc(up)", linear.SortDescType},
+}
+
+func TestSort(t *testing.T) {
+	for _, tt := range sortTests {
+		t.Run(tt.q, func(t *testing.T) {
+			q := tt.q
+			p, err := Parse(q, models.NewTagOptions())
+			require.NoError(t, err)
+			transforms, edges, err := p.DAG()
+			require.NoError(t, err)
+			assert.Len(t, transforms, 1)
+			assert.Equal(t, transforms[0].Op.OpType(), functions.FetchType)
+			assert.Equal(t, transforms[0].ID, parser.NodeID("0"))
+			assert.Len(t, edges, 0)
+		})
+	}
+}
+
 func TestTimeTypeParse(t *testing.T) {
 	q := "time()"
 	p, err := Parse(q, models.NewTagOptions())

src/query/parser/promql/types.go

@@ -171,55 +171,74 @@ func NewFunctionExpr(
 	name string,
 	argValues []interface{},
 	stringValues []string,
-) (parser.Params, error) {
+) (parser.Params, bool, error) {
+	var p parser.Params
+	var err error
+
 	switch name {
 	case linear.AbsType, linear.CeilType, linear.ExpType, linear.FloorType, linear.LnType,
 		linear.Log10Type, linear.Log2Type, linear.SqrtType:
-		return linear.NewMathOp(name)
+		p, err = linear.NewMathOp(name)
+		return p, true, err
 
 	case linear.AbsentType:
-		return linear.NewAbsentOp(), nil
+		p = linear.NewAbsentOp()
+		return p, true, err
 
 	case linear.ClampMinType, linear.ClampMaxType:
-		return linear.NewClampOp(argValues, name)
+		p, err = linear.NewClampOp(argValues, name)
+		return p, true, err
 
 	case linear.RoundType:
-		return linear.NewRoundOp(argValues)
+		p, err = linear.NewRoundOp(argValues)
+		return p, true, err
 
 	case linear.DayOfMonthType, linear.DayOfWeekType, linear.DaysInMonthType, linear.HourType,
 		linear.MinuteType, linear.MonthType, linear.YearType:
-		return linear.NewDateOp(name)
+		p, err = linear.NewDateOp(name)
+		return p, true, err
 
 	case tag.TagJoinType, tag.TagReplaceType:
-		return tag.NewTagOp(name, stringValues)
+		p, err = tag.NewTagOp(name, stringValues)
+		return p, true, err
 
 	case temporal.AvgType, temporal.CountType, temporal.MinType,
 		temporal.MaxType, temporal.SumType, temporal.StdDevType,
 		temporal.StdVarType:
-		return temporal.NewAggOp(argValues, name)
+		p, err = temporal.NewAggOp(argValues, name)
+		return p, true, err
 
 	case temporal.HoltWintersType:
-		return temporal.NewHoltWintersOp(argValues)
+		p, err = temporal.NewHoltWintersOp(argValues)
+		return p, true, err
 
 	case temporal.IRateType, temporal.IDeltaType, temporal.RateType, temporal.IncreaseType,
 		temporal.DeltaType:
-		return temporal.NewRateOp(argValues, name)
+		p, err = temporal.NewRateOp(argValues, name)
+		return p, true, err
 
 	case temporal.PredictLinearType, temporal.DerivType:
-		return temporal.NewLinearRegressionOp(argValues, name)
+		p, err = temporal.NewLinearRegressionOp(argValues, name)
+		return p, true, err
 
 	case temporal.ResetsType, temporal.ChangesType:
-		return temporal.NewFunctionOp(argValues, name)
+		p, err = temporal.NewFunctionOp(argValues, name)
+		return p, true, err
+
+	case linear.SortType, linear.SortDescType:
+		return nil, false, err
 
 	case unconsolidated.TimestampType:
-		return unconsolidated.NewTimestampOp(name)
+		p, err = unconsolidated.NewTimestampOp(name)
+		return p, true, err
 
 	case scalar.TimeType:
-		return scalar.NewScalarOp(func(t time.Time) float64 { return float64(t.Unix()) }, scalar.TimeType)
+		p, err = scalar.NewScalarOp(func(t time.Time) float64 { return float64(t.Unix()) }, scalar.TimeType)
+		return p, true, err
 
 	default:
 		// TODO: handle other types
-		return nil, fmt.Errorf("function not supported: %s", name)
+		return nil, false, fmt.Errorf("function not supported: %s", name)
 	}
 }