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

     1  package scale
     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 scale struct{}
    14  
    15  func GetOrder() interfaces.Order {
    16  	return interfaces.Any
    17  }
    18  
    19  func New(configFile string) []interfaces.FunctionMetadata {
    20  	res := make([]interfaces.FunctionMetadata, 0)
    21  	f := &scale{}
    22  	functions := []string{"scale", "scaleAfterTimestamp"}
    23  	for _, n := range functions {
    24  		res = append(res, interfaces.FunctionMetadata{Name: n, F: f})
    25  	}
    26  	return res
    27  }
    28  
    29  // scale(seriesList, factor)
    30  func (f *scale) Do(ctx context.Context, eval interfaces.Evaluator, e parser.Expr, from, until int64, values map[parser.MetricRequest][]*types.MetricData) ([]*types.MetricData, error) {
    31  	if e.ArgsLen() < 2 {
    32  		return nil, parser.ErrMissingArgument
    33  	}
    34  
    35  	arg, err := helper.GetSeriesArg(ctx, eval, e.Arg(0), from, until, values)
    36  	if err != nil {
    37  		return nil, err
    38  	}
    39  	scale, err := e.GetFloatArg(1)
    40  	if err != nil {
    41  		return nil, err
    42  	}
    43  	scaleStr := strconv.FormatFloat(scale, 'g', -1, 64)
    44  	timestamp, err := e.GetIntArgDefault(2, 0)
    45  	if err != nil {
    46  		return nil, err
    47  	}
    48  
    49  	results := make([]*types.MetricData, len(arg))
    50  	for j, a := range arg {
    51  		r := a.CopyLink()
    52  		if timestamp == 0 {
    53  			r.Name = "scale(" + a.Name + "," + scaleStr + ")"
    54  		} else {
    55  			r.Name = "scale(" + a.Name + "," + scaleStr + "," + e.Arg(2).StringValue() + ")"
    56  		}
    57  		r.Values = make([]float64, len(a.Values))
    58  		r.Tags["scale"] = scaleStr
    59  
    60  		currentTimestamp := a.StartTime
    61  		for i, v := range a.Values {
    62  			r.Values[i] = v
    63  			if currentTimestamp >= int64(timestamp) {
    64  				r.Values[i] *= scale
    65  			}
    66  
    67  			currentTimestamp += a.StepTime
    68  		}
    69  
    70  		results[j] = r
    71  	}
    72  	return results, nil
    73  }
    74  
    75  // Description is auto-generated description, based on output of https://github.com/graphite-project/graphite-web
    76  func (f *scale) Description() map[string]types.FunctionDescription {
    77  	return map[string]types.FunctionDescription{
    78  		"scale": {
    79  			Description: "Takes one metric or a wildcard seriesList followed by a constant, and multiplies the datapoint\n" +
    80  				"by the constant provided at each point.\n" +
    81  				"carbonapi extends this function by optional 3-rd parameter that accepts unix-timestamp. If provided, only values with timestamp newer than it will be scaled\n\n" +
    82  				"Example:\n\n.. code-block:: none\n\n  &target=scale(Server.instance01.threads.busy,10)\n  &target=scale(Server.instance*.threads.busy,10)\n\n" +
    83  				"Alias: scaleAfterTimestamp",
    84  			Function: "scale(seriesList, factor)",
    85  			Group:    "Transform",
    86  			Module:   "graphite.render.functions",
    87  			Name:     "scale",
    88  			Params: []types.FunctionParam{
    89  				{
    90  					Name:     "seriesList",
    91  					Required: true,
    92  					Type:     types.SeriesList,
    93  				},
    94  				{
    95  					Name:     "factor",
    96  					Required: true,
    97  					Type:     types.Float,
    98  				},
    99  				{
   100  					Name:     "timestamp",
   101  					Required: false,
   102  					Type:     types.Integer,
   103  					Default:  types.NewSuggestion(0),
   104  				},
   105  			},
   106  			NameChange:   true, // name changed
   107  			ValuesChange: true, // values changed
   108  		},
   109  		"scaleAfterTimestamp": {
   110  			Description: "Takes one metric or a wildcard seriesList followed by a constant, and multiplies the datapoint\n" +
   111  				"by the constant provided at each point.\n" +
   112  				"carbonapi extends this function by optional 3-rd parameter that accepts unix-timestamp. If provided, only values with timestamp newer than it will be scaled\n\n" +
   113  				"Example:\n\n.. code-block:: none\n\n  &target=scale(Server.instance01.threads.busy,10)\n  &target=scale(Server.instance*.threads.busy,10)",
   114  			Function: "scaleAfterTimestamp(seriesList, factor)",
   115  			Group:    "Transform",
   116  			Module:   "graphite.render.functions",
   117  			Name:     "scaleAfterTimestamp",
   118  			Params: []types.FunctionParam{
   119  				{
   120  					Name:     "seriesList",
   121  					Required: true,
   122  					Type:     types.SeriesList,
   123  				},
   124  				{
   125  					Name:     "factor",
   126  					Required: true,
   127  					Type:     types.Float,
   128  				},
   129  				{
   130  					Name:     "timestamp",
   131  					Required: false,
   132  					Type:     types.Integer,
   133  					Default:  types.NewSuggestion(0),
   134  				},
   135  			},
   136  			NameChange:   true, // name changed
   137  			ValuesChange: true, // values changed
   138  		},
   139  	}
   140  }