github.com/m3db/m3@v1.5.0/src/query/graphite/ts/series_reducer.go (about)

     1  // Copyright (c) 2019 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package ts
    22  
    23  import "fmt"
    24  
    25  // SeriesReducerApproach defines an approach to reduce a series to a single value.
    26  type SeriesReducerApproach string
    27  
    28  // The standard set of reducers
    29  const (
    30  	SeriesReducerAvg    SeriesReducerApproach = "avg"
    31  	SeriesReducerSum    SeriesReducerApproach = "sum"
    32  	SeriesReducerMin    SeriesReducerApproach = "min"
    33  	SeriesReducerMax    SeriesReducerApproach = "max"
    34  	SeriesReducerStdDev SeriesReducerApproach = "stddev"
    35  	SeriesReducerLast   SeriesReducerApproach = "last"
    36  
    37  	SeriesReducerAverage SeriesReducerApproach = "average" // alias for "avg"
    38  	SeriesReducerTotal   SeriesReducerApproach = "total"   // alias for "sum"
    39  	SeriesReducerCurrent SeriesReducerApproach = "current" // alias for "last"
    40  )
    41  
    42  // SeriesReducer reduces a series to a single value.
    43  type SeriesReducer func(*Series) float64
    44  
    45  // SafeReducer returns a boolean indicating whether it is a valid reducer,
    46  // and if so, the SeriesReducer implementing the SeriesReducerApproach.
    47  func (sa SeriesReducerApproach) SafeReducer() (SeriesReducer, bool) {
    48  	r, ok := seriesReducers[sa]
    49  	return r, ok
    50  }
    51  
    52  // Reducer returns the SeriesReducer implementing the SeriesReducerApproach.
    53  func (sa SeriesReducerApproach) Reducer() SeriesReducer {
    54  	r, ok := sa.SafeReducer()
    55  	if !ok {
    56  		panic(fmt.Sprintf("No reducer func for %s", sa))
    57  	}
    58  	return r
    59  }
    60  
    61  var seriesReducers = map[SeriesReducerApproach]SeriesReducer{
    62  	SeriesReducerAvg:     func(b *Series) float64 { return b.SafeAvg() },
    63  	SeriesReducerAverage: func(b *Series) float64 { return b.SafeAvg() },
    64  	SeriesReducerTotal:   func(b *Series) float64 { return b.SafeSum() },
    65  	SeriesReducerSum:     func(b *Series) float64 { return b.SafeSum() },
    66  	SeriesReducerMin:     func(b *Series) float64 { return b.SafeMin() },
    67  	SeriesReducerMax:     func(b *Series) float64 { return b.SafeMax() },
    68  	SeriesReducerStdDev:  func(b *Series) float64 { return b.SafeStdDev() },
    69  	SeriesReducerLast:    func(b *Series) float64 { return b.SafeLastValue() },
    70  	SeriesReducerCurrent: func(b *Series) float64 { return b.SafeLastValue() },
    71  }