diff options
Diffstat (limited to 'vendor/github.com/prometheus/client_golang/prometheus/histogram.go')
| -rw-r--r-- | vendor/github.com/prometheus/client_golang/prometheus/histogram.go | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/histogram.go b/vendor/github.com/prometheus/client_golang/prometheus/histogram.go index 8425640b3..893802fd6 100644 --- a/vendor/github.com/prometheus/client_golang/prometheus/histogram.go +++ b/vendor/github.com/prometheus/client_golang/prometheus/histogram.go @@ -116,6 +116,34 @@ func ExponentialBuckets(start, factor float64, count int) []float64 { return buckets } +// ExponentialBucketsRange creates 'count' buckets, where the lowest bucket is +// 'min' and the highest bucket is 'max'. The final +Inf bucket is not counted +// and not included in the returned slice. The returned slice is meant to be +// used for the Buckets field of HistogramOpts. +// +// The function panics if 'count' is 0 or negative, if 'min' is 0 or negative. +func ExponentialBucketsRange(min, max float64, count int) []float64 { + if count < 1 { + panic("ExponentialBucketsRange count needs a positive count") + } + if min <= 0 { + panic("ExponentialBucketsRange min needs to be greater than 0") + } + + // Formula for exponential buckets. + // max = min*growthFactor^(bucketCount-1) + + // We know max/min and highest bucket. Solve for growthFactor. + growthFactor := math.Pow(max/min, 1.0/float64(count-1)) + + // Now that we know growthFactor, solve for each bucket. + buckets := make([]float64, count) + for i := 1; i <= count; i++ { + buckets[i-1] = min * math.Pow(growthFactor, float64(i-1)) + } + return buckets +} + // HistogramOpts bundles the options for creating a Histogram metric. It is // mandatory to set Name to a non-empty string. All other fields are optional // and can safely be left at their zero value, although it is strongly |