github.com/go-graphite/carbonapi@v0.17.0/expr/functions/seriesList/function.go

package seriesList

import (
	"context"
	"math"
	"sort"
	"strconv"

	"github.com/go-graphite/carbonapi/expr/helper"
	"github.com/go-graphite/carbonapi/expr/interfaces"
	"github.com/go-graphite/carbonapi/expr/types"
	"github.com/go-graphite/carbonapi/pkg/parser"
)

type seriesList struct{}

func GetOrder() interfaces.Order {
	return interfaces.Any
}

func New(configFile string) []interfaces.FunctionMetadata {
	res := make([]interfaces.FunctionMetadata, 0)
	f := &seriesList{}
	functions := []string{"divideSeriesLists", "diffSeriesLists", "multiplySeriesLists", "powSeriesLists", "sumSeriesLists"}
	for _, n := range functions {
		res = append(res, interfaces.FunctionMetadata{Name: n, F: f})
	}
	return res
}

func (f *seriesList) Do(ctx context.Context, eval interfaces.Evaluator, e parser.Expr, from, until int64, values map[parser.MetricRequest][]*types.MetricData) ([]*types.MetricData, error) {
	if e.ArgsLen() < 2 {
		return nil, parser.ErrMissingArgument
	}

	useConstant := false
	useDenom := false

	defaultValue, err := e.GetFloatNamedOrPosArgDefault("default", 3, math.NaN())
	if err != nil {
		return nil, err
	}

	numerators, err := helper.GetSeriesArg(ctx, eval, e.Arg(0), from, until, values)
	if err != nil {
		return nil, err
	}
	if len(numerators) == 0 {
		if !math.IsNaN(defaultValue) {
			useConstant = true
			useDenom = true
		} else {
			return nil, nil
		}
	}

	denominators, err := helper.GetSeriesArg(ctx, eval, e.Arg(1), from, until, values)
	if err != nil {
		return nil, err
	}
	if len(denominators) == 0 {
		if !math.IsNaN(defaultValue) && !useConstant {
			useConstant = true
		} else {
			return nil, nil
		}
	}

	sizeMatch := len(denominators) == len(numerators) || len(denominators) == 1
	useMatching, err := e.GetBoolNamedOrPosArgDefault("matching", 2, !useConstant && !sizeMatch)
	if err != nil {
		return nil, err
	}

	sort.Slice(numerators, func(i, j int) bool { return numerators[i].Name < numerators[j].Name })
	sort.Slice(denominators, func(i, j int) bool { return denominators[i].Name < denominators[j].Name })

	functionName := e.Target()[:len(e.Target())-len("Lists")]

	var compute func(l, r float64) float64

	switch e.Target() {
	case "divideSeriesLists":
		compute = func(l, r float64) float64 { return l / r }
	case "multiplySeriesLists":
		compute = func(l, r float64) float64 { return l * r }
	case "diffSeriesLists":
		compute = func(l, r float64) float64 { return l - r }
	case "powSeriesLists":
		compute = math.Pow
	case "sumSeriesLists":
		compute = func(l, r float64) float64 { return l + r }
	}

	if useConstant {
		var single []*types.MetricData
		if useDenom {
			single = denominators
		} else {
			single = numerators
		}
		results := make([]*types.MetricData, len(single))
		for n, s := range single {
			r := s.CopyLinkTags()
			r.Name = functionName + "(" + s.Name + "," + s.Name + ")"
			r.Values = make([]float64, len(s.Values))
			for i, v := range s.Values {
				if math.IsNaN(v) {
					r.Values[i] = math.NaN()
					continue
				}

				if e.Target() == "divideSeriesLists" {
					if (useDenom && v == 0) || (!useDenom && defaultValue == 0) {
						r.Values[i] = math.NaN()
						continue
					}
				}
				if useDenom {
					r.Values[i] = compute(defaultValue, v)
				} else {
					r.Values[i] = compute(v, defaultValue)
				}

			}
			results[n] = r
		}
		return results, nil
	}

	var denomMap map[string]*types.MetricData
	if useMatching {
		denomMap = make(map[string]*types.MetricData, len(denominators))
		for _, s := range denominators {
			denomMap[s.Name] = s
		}
	}

	var denominator *types.MetricData

	results := make([]*types.MetricData, 0, len(numerators))
	for n, numerator := range numerators {
		pairFound := false
		if useMatching {
			denominator, pairFound = denomMap[numerator.Name]
			if !pairFound && math.IsNaN(defaultValue) {
				continue
			}
		} else {
			pairFound = true
			if len(denominators) == 1 {
				denominator = denominators[0]
			} else {
				denominator = denominators[n]
			}
		}
		if pairFound {
			numerator, denominator = helper.ConsolidateSeriesByStep(numerator, denominator)
		}

		r := numerator.CopyLink()
		var denomName string
		if pairFound {
			denomName = denominator.Name
		} else {
			denomName = strconv.FormatFloat(defaultValue, 'f', -1, 64)
		}
		r.Name = functionName + "(" + numerator.Name + "," + denomName + ")"
		r.Values = make([]float64, len(numerator.Values))

		for i, v := range numerator.Values {
			denomIsAbsent := pairFound && math.IsNaN(denominator.Values[i])
			if math.IsNaN(numerator.Values[i]) || denomIsAbsent {
				r.Values[i] = math.NaN()
				continue
			}

			denomValue := defaultValue
			if pairFound {
				denomValue = denominator.Values[i]
			}

			switch e.Target() {
			case "divideSeriesLists":
				if denominator.Values[i] == 0 {
					r.Values[i] = math.NaN()
					continue
				}
				r.Values[i] = compute(v, denomValue)
			default:
				r.Values[i] = compute(v, denomValue)
			}
		}
		results = append(results, r)
	}
	return results, nil
}

// Description is auto-generated description, based on output of https://github.com/graphite-project/graphite-web
func (f *seriesList) Description() map[string]types.FunctionDescription {
	return map[string]types.FunctionDescription{
		"divideSeriesLists": {
			Description: "Iterates over a two lists and divides list1[0} by list2[0}, list1[1} by list2[1} and so on.\nThe lists need to be the same length\nCarbonAPI-specific extension allows to specify default value as 3rd optional argument in case series doesn't exist or value is missing",
			Function:    "divideSeriesLists(dividendSeriesList, divisorSeriesList)",
			Group:       "Combine",
			Module:      "graphite.render.functions",
			Name:        "divideSeriesLists",
			Params: []types.FunctionParam{
				{
					Name:     "dividendSeriesList",
					Required: true,
					Type:     types.SeriesList,
				},
				{
					Name:     "divisorSeriesList",
					Required: true,
					Type:     types.SeriesList,
				},
				{
					Name:     "default",
					Required: false,
					Type:     types.Float,
				},
			},
			SeriesChange: true, // function aggregate metrics or change series items count
			NameChange:   true, // name changed
			TagsChange:   true, // name tag changed
			ValuesChange: true, // values changed
		},
		"diffSeriesLists": {
			Description: "Iterates over a two lists and substracts list1[0} by list2[0}, list1[1} by list2[1} and so on.\nThe lists need to be the same length\nCarbonAPI-specific extension allows to specify default value as 3rd optional argument in case series doesn't exist or value is missing",
			Function:    "diffSeriesLists(firstSeriesList, secondSeriesList)",
			Group:       "Combine",
			Module:      "graphite.render.functions.custom",
			Name:        "diffSeriesLists",
			Params: []types.FunctionParam{
				{
					Name:     "firstSeriesList",
					Required: true,
					Type:     types.SeriesList,
				},
				{
					Name:     "secondSeriesList",
					Required: true,
					Type:     types.SeriesList,
				},
				{
					Name:     "default",
					Required: false,
					Type:     types.Float,
				},
			},
			SeriesChange: true, // function aggregate metrics or change series items count
			NameChange:   true, // name changed
			TagsChange:   true, // name tag changed
			ValuesChange: true, // values changed
		},
		"multiplySeriesLists": {
			Description: "Iterates over a two lists and multiplies list1[0} by list2[0}, list1[1} by list2[1} and so on.\nThe lists need to be the same length\nCarbonAPI-specific extension allows to specify default value as 3rd optional argument in case series doesn't exist or value is missing",
			Function:    "multiplySeriesLists(sourceSeriesList, factorSeriesList)",
			Group:       "Combine",
			Module:      "graphite.render.functions.custom",
			Name:        "multiplySeriesLists",
			Params: []types.FunctionParam{
				{
					Name:     "sourceSeriesList",
					Required: true,
					Type:     types.SeriesList,
				},
				{
					Name:     "factorSeriesList",
					Required: true,
					Type:     types.SeriesList,
				},
				{
					Name:     "default",
					Required: false,
					Type:     types.Float,
				},
			},
			SeriesChange: true, // function aggregate metrics or change series items count
			NameChange:   true, // name changed
			TagsChange:   true, // name tag changed
			ValuesChange: true, // values changed
		},
		"powSeriesLists": {
			Description: "Iterates over a two lists and do list1[0} in power of list2[0}, list1[1} in power of  list2[1} and so on.\nThe lists need to be the same length\nCarbonAPI-specific extension allows to specify default value as 3rd optional argument in case series doesn't exist or value is missing",
			Function:    "powSeriesLists(sourceSeriesList, factorSeriesList)",
			Group:       "Combine",
			Module:      "graphite.render.functions.custom",
			Name:        "powSeriesLists",
			Params: []types.FunctionParam{
				{
					Name:     "sourceSeriesList",
					Required: true,
					Type:     types.SeriesList,
				},
				{
					Name:     "factorSeriesList",
					Required: true,
					Type:     types.SeriesList,
				},
				{
					Name:     "default",
					Required: false,
					Type:     types.Float,
				},
			},
			SeriesChange: true, // function aggregate metrics or change series items count
			NameChange:   true, // name changed
			TagsChange:   true, // name tag changed
			ValuesChange: true, // values changed
		},
		"sumSeriesLists": {
			Description: "Iterates over a two lists and subtracts series lists 2 through n from series 1 list1[0] to list2[0], list1[1] to list2[1] and so on. \n The lists will need to be the same length\nCarbonAPI-specific extension allows to specify default value as 3rd optional argument in case series doesn't exist or value is missing Example:\n\n.. code-block:: none\n\n  &target=sumSeriesLists(mining.{carbon,graphite,diamond}.extracted,mining.{carbon,graphite,diamond}.shipped)\n\n",
			Function:    "sumSeriesLists(seriesListFirstPos, seriesListSecondPos)",
			Group:       "Combine",
			Module:      "graphite.render.functions.custom",
			Name:        "sumSeriesLists",
			Params: []types.FunctionParam{
				{
					Name:     "seriesListFirstPos",
					Required: true,
					Type:     types.SeriesList,
				},
				{
					Name:     "seriesListSecondPos",
					Required: true,
					Type:     types.SeriesList,
				},
				{
					Name:     "default",
					Required: false,
					Type:     types.Float,
				},
			},
			SeriesChange: true, // function aggregate metrics or change series items count
			NameChange:   true, // name changed
			TagsChange:   true, // name tag changed
			ValuesChange: true, // values changed
		},
	}
}