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

     1  package pow
     2  
     3  import (
     4  	"context"
     5  	"math"
     6  	"strconv"
     7  
     8  	"github.com/go-graphite/carbonapi/expr/helper"
     9  	"github.com/go-graphite/carbonapi/expr/interfaces"
    10  	"github.com/go-graphite/carbonapi/expr/types"
    11  	"github.com/go-graphite/carbonapi/pkg/parser"
    12  )
    13  
    14  type pow struct{}
    15  
    16  func GetOrder() interfaces.Order {
    17  	return interfaces.Any
    18  }
    19  
    20  func New(configFile string) []interfaces.FunctionMetadata {
    21  	res := make([]interfaces.FunctionMetadata, 0)
    22  	f := &pow{}
    23  	functions := []string{"pow"}
    24  	for _, n := range functions {
    25  		res = append(res, interfaces.FunctionMetadata{Name: n, F: f})
    26  	}
    27  	return res
    28  }
    29  
    30  // pow(seriesList,factor)
    31  func (f *pow) Do(ctx context.Context, eval interfaces.Evaluator, e parser.Expr, from, until int64, values map[parser.MetricRequest][]*types.MetricData) ([]*types.MetricData, error) {
    32  	if e.ArgsLen() < 2 {
    33  		return nil, parser.ErrMissingArgument
    34  	}
    35  
    36  	arg, err := helper.GetSeriesArg(ctx, eval, e.Arg(0), from, until, values)
    37  	if err != nil {
    38  		return nil, err
    39  	}
    40  	factor, err := e.GetFloatArg(1)
    41  	if err != nil {
    42  		return nil, err
    43  	}
    44  	factorStr := strconv.FormatFloat(factor, 'g', -1, 64)
    45  	results := make([]*types.MetricData, len(arg))
    46  
    47  	for j, a := range arg {
    48  		r := a.CopyLink()
    49  		r.Name = "pow(" + a.Name + "," + factorStr + ")"
    50  		r.Values = make([]float64, len(a.Values))
    51  		r.Tags["pow"] = factorStr
    52  
    53  		for i, v := range a.Values {
    54  			if math.IsNaN(v) {
    55  				r.Values[i] = math.NaN()
    56  			} else {
    57  				r.Values[i] = math.Pow(v, factor)
    58  			}
    59  		}
    60  		results[j] = r
    61  	}
    62  	return results, nil
    63  }
    64  
    65  // Description is auto-generated description, based on output of https://github.com/graphite-project/graphite-web
    66  func (f *pow) Description() map[string]types.FunctionDescription {
    67  	return map[string]types.FunctionDescription{
    68  		"pow": {
    69  			Description: "Takes one metric or a wildcard seriesList followed by a constant, and raises the datapoint\nby the power of the constant provided at each point.\n\nExample:\n\n.. code-block:: none\n\n  &target=pow(Server.instance01.threads.busy,10)\n  &target=pow(Server.instance*.threads.busy,10)",
    70  			Function:    "pow(seriesList, factor)",
    71  			Group:       "Transform",
    72  			Module:      "graphite.render.functions",
    73  			Name:        "pow",
    74  			Params: []types.FunctionParam{
    75  				{
    76  					Name:     "seriesList",
    77  					Required: true,
    78  					Type:     types.SeriesList,
    79  				},
    80  				{
    81  					Name:     "factor",
    82  					Required: true,
    83  					Type:     types.Float,
    84  				},
    85  			},
    86  			NameChange:   true, // name changed
    87  			ValuesChange: true, // values changed
    88  		},
    89  	}
    90  }