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

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