From 9c4fec0bcee25c9ab6fe98cbf0d93f73e3f67896 Mon Sep 17 00:00:00 2001 From: Bjoern Rabenstein Date: Mon, 4 May 2015 00:32:15 +0200 Subject: [PATCH] Implement constSummary and constHistogram. --- prometheus/histogram.go | 99 +++++++++++++++++++++++++++++++++++++++++ prometheus/summary.go | 86 +++++++++++++++++++++++++++++++++++ 2 files changed, 185 insertions(+) diff --git a/prometheus/histogram.go b/prometheus/histogram.go index 9b36a61..eb531e2 100644 --- a/prometheus/histogram.go +++ b/prometheus/histogram.go @@ -342,3 +342,102 @@ func (m *HistogramVec) WithLabelValues(lvs ...string) Histogram { func (m *HistogramVec) With(labels Labels) Histogram { return m.MetricVec.With(labels).(Histogram) } + +type constHistogram struct { + desc *Desc + count uint64 + sum float64 + buckets map[float64]uint64 + labelPairs []*dto.LabelPair +} + +func (h *constHistogram) Desc() *Desc { + return h.desc +} + +func (h *constHistogram) Write(out *dto.Metric) error { + his := &dto.Histogram{} + buckets := make([]*dto.Bucket, 0, len(h.buckets)) + + his.SampleCount = proto.Uint64(h.count) + his.SampleSum = proto.Float64(h.sum) + + for upperBound, count := range h.buckets { + buckets = append(buckets, &dto.Bucket{ + CumulativeCount: proto.Uint64(count), + UpperBound: proto.Float64(upperBound), + }) + } + + if len(buckets) > 0 { + sort.Sort(buckSort(buckets)) + } + his.Bucket = buckets + + out.Histogram = his + out.Label = h.labelPairs + + return nil +} + +// NewConstHistogram returns a metric representing a Prometheus histogram with fixed +// values for the count, sum, and quantiles. As those parameters cannot be +// changed, the returned value does not implement the Histogram interface (but +// only the Metric interface). Users of this package will not have much use for +// it in regular operations. However, when implementing custom Collectors, it is +// useful as a throw-away metric that is generated on the fly to send it to +// Prometheus in the Collect method. +// +// buckets is a map of upper bounds to cumulative counts, excluding the +Inf +// bucket. +// +// NewConstHistogram returns an error if the length of labelValues is not +// consistent with the variable labels in Desc. +func NewConstHistogram( + desc *Desc, + count uint64, + sum float64, + buckets map[float64]uint64, + labelValues ...string, +) (Metric, error) { + if len(desc.variableLabels) != len(labelValues) { + return nil, errInconsistentCardinality + } + return &constHistogram{ + desc: desc, + count: count, + sum: sum, + buckets: buckets, + labelPairs: makeLabelPairs(desc, labelValues), + }, nil +} + +// MustNewConstHistogram is a version of NewConstHistogram that panics where +// NewConstMetric would have returned an error. +func MustNewConstHistogram( + desc *Desc, + count uint64, + sum float64, + buckets map[float64]uint64, + labelValues ...string, +) Metric { + m, err := NewConstHistogram(desc, count, sum, buckets, labelValues...) + if err != nil { + panic(err) + } + return m +} + +type buckSort []*dto.Bucket + +func (s buckSort) Len() int { + return len(s) +} + +func (s buckSort) Swap(i, j int) { + s[i], s[j] = s[j], s[i] +} + +func (s buckSort) Less(i, j int) bool { + return s[i].GetUpperBound() < s[j].GetUpperBound() +} diff --git a/prometheus/summary.go b/prometheus/summary.go index dd336c5..67fe43c 100644 --- a/prometheus/summary.go +++ b/prometheus/summary.go @@ -448,3 +448,89 @@ func (m *SummaryVec) WithLabelValues(lvs ...string) Summary { func (m *SummaryVec) With(labels Labels) Summary { return m.MetricVec.With(labels).(Summary) } + +type constSummary struct { + desc *Desc + count uint64 + sum float64 + quantiles map[float64]float64 + labelPairs []*dto.LabelPair +} + +func (s *constSummary) Desc() *Desc { + return s.desc +} + +func (s *constSummary) Write(out *dto.Metric) error { + sum := &dto.Summary{} + qs := make([]*dto.Quantile, 0, len(s.quantiles)) + + sum.SampleCount = proto.Uint64(s.count) + sum.SampleSum = proto.Float64(s.sum) + + for rank, q := range s.quantiles { + qs = append(qs, &dto.Quantile{ + Quantile: proto.Float64(rank), + Value: proto.Float64(q), + }) + } + + if len(qs) > 0 { + sort.Sort(quantSort(qs)) + } + sum.Quantile = qs + + out.Summary = sum + out.Label = s.labelPairs + + return nil +} + +// NewConstSummary returns a metric representing a Prometheus summary with fixed +// values for the count, sum, and quantiles. As those parameters cannot be +// changed, the returned value does not implement the Summary interface (but +// only the Metric interface). Users of this package will not have much use for +// it in regular operations. However, when implementing custom Collectors, it is +// useful as a throw-away metric that is generated on the fly to send it to +// Prometheus in the Collect method. +// +// quantiles maps ranks to quantile values. For example, a median latency of +// 0.23s and a 99th percentile latency of 0.56s would be expressed as: +// map[float64]float64{0.5: 0.23, 0.99: 0.56} +// +// NewConstSummary returns an error if the length of labelValues is not +// consistent with the variable labels in Desc. +func NewConstSummary( + desc *Desc, + count uint64, + sum float64, + quantiles map[float64]float64, + labelValues ...string, +) (Metric, error) { + if len(desc.variableLabels) != len(labelValues) { + return nil, errInconsistentCardinality + } + return &constSummary{ + desc: desc, + count: count, + sum: sum, + quantiles: quantiles, + labelPairs: makeLabelPairs(desc, labelValues), + }, nil +} + +// MustNewConstSummary is a version of NewConstSummary that panics where +// NewConstMetric would have returned an error. +func MustNewConstSummary( + desc *Desc, + count uint64, + sum float64, + quantiles map[float64]float64, + labelValues ...string, +) Metric { + m, err := NewConstSummary(desc, count, sum, quantiles, labelValues...) + if err != nil { + panic(err) + } + return m +}