func_removeemptyseries.go

package expr

import (
	"math"

	"github.com/grafana/metrictank/api/models"
)

type FuncRemoveEmptySeries struct {
	in           GraphiteFunc
	xFilesFactor float64
}

func NewRemoveEmptySeries() GraphiteFunc {
	return &FuncRemoveEmptySeries{xFilesFactor: 0}
}

func (s *FuncRemoveEmptySeries) Signature() ([]Arg, []Arg) {

	return []Arg{
			ArgSeriesList{val: &s.in},
			ArgFloat{key: "xFilesFactor", val: &s.xFilesFactor, opt: true, validator: []Validator{WithinZeroOneInclusiveInterval}},
		}, []Arg{
			ArgSeriesList{},
		}
}

func (s *FuncRemoveEmptySeries) Context(context Context) Context {
	return context
}

func (s *FuncRemoveEmptySeries) Exec(dataMap DataMap) ([]models.Series, error) {
	series, err := s.in.Exec(dataMap)
	if err != nil {
		return nil, err
	}

	if math.IsNaN(s.xFilesFactor) {
		s.xFilesFactor = 0.0
	}

	var output []models.Series
	for _, serie := range series {
		notNull := 0
		for _, p := range serie.Datapoints {
			if !math.IsNaN(p.Val) {
				notNull++
			}
		}

		if xffCheck(notNull, len(serie.Datapoints), s.xFilesFactor) {
			output = append(output, serie)
		}
	}

	return output, nil
}

// xffCheck returns whether a series with given notNull and total point counts should be included based on the xFilesFactor
func xffCheck(notNull int, total int, xFilesFactor float64) bool {
	if notNull == 0 || total == 0 {
		return false
	}

	return float64(notNull)/float64(total) >= xFilesFactor
}