github.com/go-graphite/carbonapi@v0.17.0/expr/functions/nPercentile/function.go (about)

     1  package nPercentile
     2  
     3  import (
     4  	"context"
     5  	"math"
     6  	"strconv"
     7  
     8  	"github.com/go-graphite/carbonapi/expr/consolidations"
     9  	"github.com/go-graphite/carbonapi/expr/helper"
    10  	"github.com/go-graphite/carbonapi/expr/interfaces"
    11  	"github.com/go-graphite/carbonapi/expr/types"
    12  	"github.com/go-graphite/carbonapi/pkg/parser"
    13  )
    14  
    15  type nPercentile struct{}
    16  
    17  func GetOrder() interfaces.Order {
    18  	return interfaces.Any
    19  }
    20  
    21  func New(configFile string) []interfaces.FunctionMetadata {
    22  	res := make([]interfaces.FunctionMetadata, 0)
    23  	f := &nPercentile{}
    24  	functions := []string{"nPercentile"}
    25  	for _, n := range functions {
    26  		res = append(res, interfaces.FunctionMetadata{Name: n, F: f})
    27  	}
    28  	return res
    29  }
    30  
    31  // nPercentile(seriesList, n)
    32  func (f *nPercentile) Do(ctx context.Context, eval interfaces.Evaluator, e parser.Expr, from, until int64, values map[parser.MetricRequest][]*types.MetricData) ([]*types.MetricData, error) {
    33  	if e.ArgsLen() < 2 {
    34  		return nil, parser.ErrMissingArgument
    35  	}
    36  
    37  	arg, err := helper.GetSeriesArg(ctx, eval, e.Arg(0), from, until, values)
    38  	if err != nil {
    39  		return nil, err
    40  	}
    41  	percent, err := e.GetFloatArg(1)
    42  	if err != nil {
    43  		return nil, err
    44  	}
    45  	percentStr := strconv.FormatFloat(percent, 'g', -1, 64)
    46  
    47  	results := make([]*types.MetricData, len(arg))
    48  	for i, a := range arg {
    49  		r := a.CopyLink()
    50  		r.Name = "nPercentile(" + a.Name + "," + percentStr + ")"
    51  		r.Values = make([]float64, len(a.Values))
    52  		r.Tags["nPercentile"] = percentStr
    53  		var values []float64
    54  		for _, v := range a.Values {
    55  			if !math.IsNaN(v) {
    56  				values = append(values, v)
    57  			}
    58  		}
    59  
    60  		value := consolidations.Percentile(values, percent, true)
    61  		for i := range r.Values {
    62  			r.Values[i] = value
    63  		}
    64  
    65  		results[i] = r
    66  	}
    67  	return results, nil
    68  }
    69  
    70  // Description is auto-generated description, based on output of https://github.com/graphite-project/graphite-web
    71  func (f *nPercentile) Description() map[string]types.FunctionDescription {
    72  	return map[string]types.FunctionDescription{
    73  		"nPercentile": {
    74  			Description: "Returns n-percent of each series in the seriesList.",
    75  			Function:    "nPercentile(seriesList, n)",
    76  			Group:       "Calculate",
    77  			Module:      "graphite.render.functions",
    78  			Name:        "nPercentile",
    79  			Params: []types.FunctionParam{
    80  				{
    81  					Name:     "seriesList",
    82  					Required: true,
    83  					Type:     types.SeriesList,
    84  				},
    85  				{
    86  					Name:     "n",
    87  					Required: true,
    88  					Type:     types.Integer,
    89  				},
    90  			},
    91  			NameChange:   true, // name changed
    92  			ValuesChange: true, // values changed
    93  		},
    94  	}
    95  }