cmd/bosun: series func to create series from scalars

cmd/bosun/expr/expr.go

@@ -629,7 +629,16 @@ func (e *State) walkFunc(node *parse.FuncNode, T miniprofiler.Timer) *Results {
 			default:
 				panic(fmt.Errorf("expr: unknown func arg type"))
 			}
-			if f, ok := v.(float64); ok && node.F.Args[i] == models.TypeNumberSet {
+			var argType models.FuncType
+			if i >= len(node.F.Args) {
+				if !node.F.VArgs {
+					panic("expr: shouldn't be here, more args then expected and not variable argument type func")
+				}
+				argType = node.F.Args[node.F.VArgsPos]
+			} else {
+				argType = node.F.Args[i]
+			}
+			if f, ok := v.(float64); ok && argType == models.TypeNumberSet {
 				v = fromScalar(f)
 			}
 			in = append(in, reflect.ValueOf(v))

cmd/bosun/expr/funcs.go

@@ -331,6 +331,15 @@ var builtins = map[string]parse.Func{
 		Tags:   tagFirst,
 		F:      NV,
 	},
+	"series": {
+		Args:      []models.FuncType{models.TypeString, models.TypeScalar},
+		VArgs:     true,
+		VArgsPos:  1,
+		VArgsOmit: true,
+		Return:    models.TypeSeriesSet,
+		Tags:      tagFirst,
+		F:         SeriesFunc,
+	},
 	"sort": {
 		Args:   []models.FuncType{models.TypeNumberSet, models.TypeString},
 		Return: models.TypeNumberSet,
@@ -352,6 +361,28 @@ var builtins = map[string]parse.Func{
 	},
 }
 
+func SeriesFunc(e *State, T miniprofiler.Timer, tags string, pairs ...float64) (*Results, error) {
+	if len(pairs)%2 != 0 {
+		return nil, fmt.Errorf("uneven number of time stamps and values")
+	}
+	group, err := opentsdb.ParseTags(tags)
+	if err != nil {
+		return nil, fmt.Errorf("unable to parse tags: %v", err)
+	}
+	series := make(Series)
+	for i := 0; i < len(pairs); i += 2 {
+		series[time.Unix(int64(pairs[i]), 0)] = pairs[i+1]
+	}
+	return &Results{
+		Results: []*Result{
+			{
+				Value: series,
+				Group: group,
+			},
+		},
+	}, nil
+}
+
 func Epoch(e *State, T miniprofiler.Timer) (*Results, error) {
 	return &Results{
 		Results: []*Result{
@@ -361,6 +392,11 @@ func Epoch(e *State, T miniprofiler.Timer) (*Results, error) {
 }
 
 func NV(e *State, T miniprofiler.Timer, series *Results, v float64) (results *Results, err error) {
+	// If there are no results in the set, promote it to a number with the empty group ({})
+	if len(series.Results) == 0 {
+		series.Results = append(series.Results, &Result{Value: Number(v), Group: make(opentsdb.TagSet)})
+		return series, nil
+	}
 	series.NaNValue = &v
 	return series, nil
 }

cmd/bosun/expr/parse/node.go

@@ -107,7 +107,7 @@ func (f *FuncNode) Check(t *Tree) error {
 	const errFuncType = "parse: bad argument type in %s, expected %s, got %s"
 	// For VArgs we make sure they are all of the expected type
 	if f.F.VArgs {
-		if len(f.Args) < len(f.F.Args) {
+		if len(f.Args) < len(f.F.Args) && !f.F.VArgsOmit {
 			return fmt.Errorf("parse: variable argument functions need at least one arg")
 		}
 	} else {

cmd/bosun/expr/parse/parse.go

@@ -31,13 +31,14 @@ type Tree struct {
 }
 
 type Func struct {
-	Args     []models.FuncType
-	Return   models.FuncType
-	Tags     func([]Node) (Tags, error)
-	F        interface{}
-	VArgs    bool
-	VArgsPos int
-	Check    func(*Tree, *FuncNode) error
+	Args      []models.FuncType
+	Return    models.FuncType
+	Tags      func([]Node) (Tags, error)
+	F         interface{}
+	VArgs     bool
+	VArgsPos  int
+	VArgsOmit bool
+	Check     func(*Tree, *FuncNode) error
 }
 
 type Tags map[string]struct{}

cmd/bosun/expr/parse/parse_test.go

@@ -158,6 +158,7 @@ var builtins = map[string]Func{
 		nil,
 		false,
 		0,
+		false,
 		nil,
 	},
 	"band": {
@@ -167,6 +168,7 @@ var builtins = map[string]Func{
 		nil,
 		false,
 		0,
+		false,
 		nil,
 	},
 	"q": {
@@ -176,6 +178,7 @@ var builtins = map[string]Func{
 		nil,
 		false,
 		0,
+		false,
 		nil,
 	},
 	"forecastlr": {
@@ -185,6 +188,7 @@ var builtins = map[string]Func{
 		nil,
 		false,
 		0,
+		false,
 		nil,
 	},
 }

docs/expressions.md

@@ -494,7 +494,17 @@ Returns the first count (scalar) results of number.
 
 Returns the first key from the given lookup table with matching tags.
 
-##shift(seriesSet, dur string) seriesSet
+## series(tagset string, epoch, value, ...) seriesSet
+
+Returns a seriesSet with one series. The series will have a group (a.k.a tagset). You can then optionally pass epoch value pairs (if non are provided, the series will be empty). This is can be used for testing or drawing arbitary lines. For example:
+
+```
+$now = epoch()
+$hourAgo =  $now-d("1h")
+merge(series("foo=bar", $hourAgo, 5, $now, 10), series("foo=bar2", $hourAgo, 6, $now, 11))
+```
+
+## shift(seriesSet, dur string) seriesSet
 
 Shift takes a seriesSet and shifts the time forward by the value of dur ([OpenTSDB duration string](http://opentsdb.net/docs/build/html/user_guide/query/dates.html)) and adds a tag for representing the shift duration. This is meant so you can overlay times visually in a graph.