github.com/inspektor-gadget/inspektor-gadget@v0.28.1/pkg/operators/prometheus/bucket.go (about)

     1  // Copyright 2023 The Inspektor Gadget authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package prometheus
    16  
    17  import (
    18  	"math"
    19  	"strings"
    20  
    21  	"github.com/shopspring/decimal"
    22  	log "github.com/sirupsen/logrus"
    23  
    24  	"github.com/inspektor-gadget/inspektor-gadget/pkg/prometheus/config"
    25  )
    26  
    27  type BucketType string
    28  
    29  const (
    30  	BucketTypeExp2   BucketType = "exp2"
    31  	BucketTypeLinear BucketType = "linear"
    32  )
    33  
    34  var AllBucketTypes = map[string]struct{}{
    35  	string(BucketTypeExp2):   {},
    36  	string(BucketTypeLinear): {},
    37  }
    38  
    39  type BucketConfig struct {
    40  	Type       BucketType
    41  	Min        int
    42  	Max        int
    43  	Multiplier float64
    44  }
    45  
    46  func bucketConfigsFromConfig(c *config.Config) map[string]*BucketConfig {
    47  	buckets := make(map[string]*BucketConfig)
    48  	for _, m := range c.Metrics {
    49  		if strings.ToLower(m.Type) == "histogram" {
    50  			buckets[m.Name] = &BucketConfig{
    51  				Type:       BucketType(m.Bucket.Type),
    52  				Min:        m.Bucket.Min,
    53  				Max:        m.Bucket.Max,
    54  				Multiplier: m.Bucket.Multiplier,
    55  			}
    56  		}
    57  	}
    58  	return buckets
    59  }
    60  
    61  func (c *BucketConfig) buckets() []float64 {
    62  	switch c.Type {
    63  	case BucketTypeExp2:
    64  		return exp2Buckets(c.Min, c.Max, c.Multiplier)
    65  	case BucketTypeLinear:
    66  		return linearBuckets(c.Min, c.Max, c.Multiplier)
    67  	default:
    68  		log.Warnf("unknown bucket type: %s", c.Type)
    69  		return nil
    70  	}
    71  }
    72  
    73  func exp2Buckets(min, max int, multiplier float64) []float64 {
    74  	buckets := make([]float64, 0, max-min)
    75  	for i := min; i < max; i++ {
    76  		buckets = append(buckets, math.Pow(2, float64(i))*multiplier)
    77  	}
    78  	return buckets
    79  }
    80  
    81  func linearBuckets(min, max int, multiplier float64) []float64 {
    82  	buckets := make([]float64, 0, max-min)
    83  	for i := min; i < max; i++ {
    84  		bucketId := decimal.NewFromInt(int64(i))
    85  		bucketValue, _ := bucketId.Mul(decimal.NewFromFloat(multiplier)).Float64()
    86  		buckets = append(buckets, bucketValue)
    87  	}
    88  	return buckets
    89  }