Add exemplars to counter and histogram
Signed-off-by: beorn7 <beorn@grafana.com>
This commit is contained in:
parent
803ef2a759
commit
57d41259e1
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@ -18,6 +18,7 @@ package main
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import (
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"flag"
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"fmt"
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"log"
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"math"
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"math/rand"
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@ -89,7 +90,11 @@ func main() {
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for {
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v := (rand.NormFloat64() * *normDomain) + *normMean
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rpcDurations.WithLabelValues("normal").Observe(v)
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rpcDurationsHistogram.Observe(v)
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rpcDurationsHistogram.ObserveWithExemplar(
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// Demonstrate exemplar support with a dummy ID. This would be
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// something like a trace ID in a real application.
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v, prometheus.Labels{"dummyID": fmt.Sprint(rand.Intn(100000))},
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)
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time.Sleep(time.Duration(75*oscillationFactor()) * time.Millisecond)
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}
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}()
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@ -103,6 +108,12 @@ func main() {
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}()
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// Expose the registered metrics via HTTP.
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http.Handle("/metrics", promhttp.Handler())
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http.Handle("/metrics", promhttp.HandlerFor(
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prometheus.DefaultGatherer,
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promhttp.HandlerOpts{
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// Opt into OpenMetrics to support exemplars.
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EnableOpenMetrics: true,
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},
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))
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log.Fatal(http.ListenAndServe(*addr, nil))
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}
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4
go.mod
4
go.mod
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@ -5,8 +5,8 @@ require (
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github.com/cespare/xxhash/v2 v2.1.1
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github.com/golang/protobuf v1.3.2
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github.com/json-iterator/go v1.1.8
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github.com/prometheus/client_model v0.1.0
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github.com/prometheus/common v0.7.0
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github.com/prometheus/client_model v0.2.0
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github.com/prometheus/common v0.9.0
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github.com/prometheus/procfs v0.0.8
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golang.org/x/sys v0.0.0-20191220142924-d4481acd189f
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)
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10
go.sum
10
go.sum
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@ -58,12 +58,12 @@ github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910 h1:idejC8f
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github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910/go.mod h1:MbSGuTsp3dbXC40dX6PRTWyKYBIrTGTE9sqQNg2J8bo=
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github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90 h1:S/YWwWx/RA8rT8tKFRuGUZhuA90OyIBpPCXkcbwU8DE=
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github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
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github.com/prometheus/client_model v0.1.0 h1:ElTg5tNp4DqfV7UQjDqv2+RJlNzsDtvNAWccbItceIE=
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github.com/prometheus/client_model v0.1.0/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
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github.com/prometheus/client_model v0.2.0 h1:uq5h0d+GuxiXLJLNABMgp2qUWDPiLvgCzz2dUR+/W/M=
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github.com/prometheus/client_model v0.2.0/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
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github.com/prometheus/common v0.4.1 h1:K0MGApIoQvMw27RTdJkPbr3JZ7DNbtxQNyi5STVM6Kw=
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github.com/prometheus/common v0.4.1/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
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github.com/prometheus/common v0.7.0 h1:L+1lyG48J1zAQXA3RBX/nG/B3gjlHq0zTt2tlbJLyCY=
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github.com/prometheus/common v0.7.0/go.mod h1:DjGbpBbp5NYNiECxcL/VnbXCCaQpKd3tt26CguLLsqA=
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github.com/prometheus/common v0.9.0 h1:yg//x/8DqN+PxXTBFMwVCopGqDn3wSxmbF/3PCuu1bk=
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github.com/prometheus/common v0.9.0/go.mod h1:yhUN8i9wzaXS3w1O07YhxHEBxD+W35wd8bs7vj7HSQ4=
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github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
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github.com/prometheus/procfs v0.0.2 h1:6LJUbpNm42llc4HRCuvApCSWB/WfhuNo9K98Q9sNGfs=
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github.com/prometheus/procfs v0.0.2/go.mod h1:TjEm7ze935MbeOT/UhFTIMYKhuLP4wbCsTZCD3I8kEA=
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@ -97,4 +97,4 @@ golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
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gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
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gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
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gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
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gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
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gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
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@ -17,6 +17,7 @@ import (
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"errors"
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"math"
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"sync/atomic"
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"time"
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dto "github.com/prometheus/client_model/go"
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)
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@ -40,6 +41,14 @@ type Counter interface {
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// Add adds the given value to the counter. It panics if the value is <
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// 0.
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Add(float64)
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// AddWithExemplar works like Add but also replaces the currently saved
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// exemplar (if any) with a new one, created from the provided value,
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// the current time as timestamp, and the provided labels. Empty Labels
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// will lead to a valid (label-less) exemplar. But if Labels is nil, the
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// current exemplar is left in place. This method panics if the value is
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// < 0, if any of the provided labels are invalid, or if the provided
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// labels contain more than 64 runes in total.
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AddWithExemplar(value float64, exemplar Labels)
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}
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// CounterOpts is an alias for Opts. See there for doc comments.
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@ -78,6 +87,7 @@ type counter struct {
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desc *Desc
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labelPairs []*dto.LabelPair
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exemplar atomic.Value // Containing nil or a *dto.Exemplar.
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}
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func (c *counter) Desc() *Desc {
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@ -88,6 +98,7 @@ func (c *counter) Add(v float64) {
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if v < 0 {
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panic(errors.New("counter cannot decrease in value"))
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}
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ival := uint64(v)
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if float64(ival) == v {
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atomic.AddUint64(&c.valInt, ival)
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@ -103,6 +114,11 @@ func (c *counter) Add(v float64) {
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}
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}
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func (c *counter) AddWithExemplar(v float64, e Labels) {
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c.Add(v)
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c.updateExemplar(v, e)
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}
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func (c *counter) Inc() {
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atomic.AddUint64(&c.valInt, 1)
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}
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@ -112,7 +128,23 @@ func (c *counter) Write(out *dto.Metric) error {
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ival := atomic.LoadUint64(&c.valInt)
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val := fval + float64(ival)
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return populateMetric(CounterValue, val, c.labelPairs, out)
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var exemplar *dto.Exemplar
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if e := c.exemplar.Load(); e != nil {
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exemplar = e.(*dto.Exemplar)
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}
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return populateMetric(CounterValue, val, c.labelPairs, exemplar, out)
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}
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func (c *counter) updateExemplar(v float64, l Labels) {
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if l == nil {
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return
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}
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e, err := newExemplar(v, time.Now(), l)
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if err != nil {
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panic(err)
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}
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c.exemplar.Store(e)
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}
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// CounterVec is a Collector that bundles a set of Counters that all share the
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@ -123,7 +123,7 @@ func (g *gauge) Sub(val float64) {
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func (g *gauge) Write(out *dto.Metric) error {
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val := math.Float64frombits(atomic.LoadUint64(&g.valBits))
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return populateMetric(GaugeValue, val, g.labelPairs, out)
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return populateMetric(GaugeValue, val, g.labelPairs, nil, out)
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}
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// GaugeVec is a Collector that bundles a set of Gauges that all share the same
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@ -20,6 +20,7 @@ import (
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"sort"
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"sync"
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"sync/atomic"
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"time"
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"github.com/golang/protobuf/proto"
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@ -47,6 +48,15 @@ type Histogram interface {
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// Observe adds a single observation to the histogram.
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Observe(float64)
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// ObserveWithExemplar works like Observe but also replaces the
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// currently saved exemplar for the relevant bucket (possibly none) with
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// a new one, created from the provided value, the current time as
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// timestamp, and the provided Labels. Empty Labels will lead to a valid
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// (label-less) exemplar. But if Labels is nil, the current exemplar in
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// the relevant bucket is left in place. This method panics if any of
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// the provided labels are invalid or if the provided labels contain
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// more than 64 runes in total.
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ObserveWithExemplar(value float64, exemplar Labels)
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}
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// bucketLabel is used for the label that defines the upper bound of a
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@ -205,9 +215,10 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
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}
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}
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// Finally we know the final length of h.upperBounds and can make buckets
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// for both counts:
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// for both counts as well as exemplars:
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h.counts[0].buckets = make([]uint64, len(h.upperBounds))
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h.counts[1].buckets = make([]uint64, len(h.upperBounds))
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h.exemplars = make([]atomic.Value, len(h.upperBounds)+1)
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h.init(h) // Init self-collection.
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return h
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@ -254,6 +265,7 @@ type histogram struct {
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upperBounds []float64
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labelPairs []*dto.LabelPair
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exemplars []atomic.Value // One more than buckets (to include +Inf), each a *dto.Exemplar.
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}
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func (h *histogram) Desc() *Desc {
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@ -261,36 +273,13 @@ func (h *histogram) Desc() *Desc {
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}
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func (h *histogram) Observe(v float64) {
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// TODO(beorn7): For small numbers of buckets (<30), a linear search is
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// slightly faster than the binary search. If we really care, we could
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// switch from one search strategy to the other depending on the number
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// of buckets.
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//
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// Microbenchmarks (BenchmarkHistogramNoLabels):
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// 11 buckets: 38.3 ns/op linear - binary 48.7 ns/op
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// 100 buckets: 78.1 ns/op linear - binary 54.9 ns/op
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// 300 buckets: 154 ns/op linear - binary 61.6 ns/op
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i := sort.SearchFloat64s(h.upperBounds, v)
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h.observe(v, h.findBucket(v))
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}
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// We increment h.countAndHotIdx so that the counter in the lower
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// 63 bits gets incremented. At the same time, we get the new value
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// back, which we can use to find the currently-hot counts.
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n := atomic.AddUint64(&h.countAndHotIdx, 1)
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hotCounts := h.counts[n>>63]
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if i < len(h.upperBounds) {
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atomic.AddUint64(&hotCounts.buckets[i], 1)
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}
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for {
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oldBits := atomic.LoadUint64(&hotCounts.sumBits)
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newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
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if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
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break
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}
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}
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// Increment count last as we take it as a signal that the observation
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// is complete.
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atomic.AddUint64(&hotCounts.count, 1)
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func (h *histogram) ObserveWithExemplar(v float64, e Labels) {
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i := h.findBucket(v)
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h.observe(v, i)
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h.updateExemplar(v, i, e)
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}
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func (h *histogram) Write(out *dto.Metric) error {
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@ -329,6 +318,18 @@ func (h *histogram) Write(out *dto.Metric) error {
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CumulativeCount: proto.Uint64(cumCount),
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UpperBound: proto.Float64(upperBound),
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}
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if e := h.exemplars[i].Load(); e != nil {
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his.Bucket[i].Exemplar = e.(*dto.Exemplar)
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}
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}
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// If there is an exemplar for the +Inf bucket, we have to add that bucket explicitly.
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if e := h.exemplars[len(h.upperBounds)].Load(); e != nil {
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b := &dto.Bucket{
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CumulativeCount: proto.Uint64(count),
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UpperBound: proto.Float64(math.Inf(1)),
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Exemplar: e.(*dto.Exemplar),
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}
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his.Bucket = append(his.Bucket, b)
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}
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out.Histogram = his
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@ -352,6 +353,57 @@ func (h *histogram) Write(out *dto.Metric) error {
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return nil
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}
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// findBucket returns the index of the bucket for the provided value, or
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// len(h.upperBounds) for the +Inf bucket.
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func (h *histogram) findBucket(v float64) int {
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// TODO(beorn7): For small numbers of buckets (<30), a linear search is
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// slightly faster than the binary search. If we really care, we could
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// switch from one search strategy to the other depending on the number
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// of buckets.
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//
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// Microbenchmarks (BenchmarkHistogramNoLabels):
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// 11 buckets: 38.3 ns/op linear - binary 48.7 ns/op
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// 100 buckets: 78.1 ns/op linear - binary 54.9 ns/op
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// 300 buckets: 154 ns/op linear - binary 61.6 ns/op
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return sort.SearchFloat64s(h.upperBounds, v)
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}
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// observe is the implementation for Observe without the findBucket part.
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func (h *histogram) observe(v float64, bucket int) {
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// We increment h.countAndHotIdx so that the counter in the lower
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// 63 bits gets incremented. At the same time, we get the new value
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// back, which we can use to find the currently-hot counts.
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n := atomic.AddUint64(&h.countAndHotIdx, 1)
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hotCounts := h.counts[n>>63]
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if bucket < len(h.upperBounds) {
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atomic.AddUint64(&hotCounts.buckets[bucket], 1)
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}
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for {
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oldBits := atomic.LoadUint64(&hotCounts.sumBits)
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newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
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if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
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break
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}
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}
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// Increment count last as we take it as a signal that the observation
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// is complete.
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atomic.AddUint64(&hotCounts.count, 1)
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}
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// updateExemplar replaces the exemplar for the provided bucket. With empty
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// labels, it's a no-op. It panics if any of the labels is invalid.
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func (h *histogram) updateExemplar(v float64, bucket int, l Labels) {
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if l == nil {
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return
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}
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e, err := newExemplar(v, time.Now(), l)
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if err != nil {
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panic(err)
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}
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h.exemplars[bucket].Store(e)
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}
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// HistogramVec is a Collector that bundles a set of Histograms that all share the
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// same Desc, but have different values for their variable labels. This is used
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// if you want to count the same thing partitioned by various dimensions
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@ -144,7 +144,12 @@ func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
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}
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}
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contentType := expfmt.Negotiate(req.Header)
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var contentType expfmt.Format
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if opts.EnableOpenMetrics {
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contentType = expfmt.NegotiateIncludingOpenMetrics(req.Header)
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} else {
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contentType = expfmt.Negotiate(req.Header)
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}
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header := rsp.Header()
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header.Set(contentTypeHeader, string(contentType))
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@ -163,22 +168,38 @@ func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
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enc := expfmt.NewEncoder(w, contentType)
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var lastErr error
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// handleError handles the error according to opts.ErrorHandling
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// and returns true if we have to abort after the handling.
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handleError := func(err error) bool {
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if err == nil {
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return false
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}
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lastErr = err
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if opts.ErrorLog != nil {
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opts.ErrorLog.Println("error encoding and sending metric family:", err)
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}
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errCnt.WithLabelValues("encoding").Inc()
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switch opts.ErrorHandling {
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case PanicOnError:
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panic(err)
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case HTTPErrorOnError:
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httpError(rsp, err)
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return true
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}
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// Do nothing in all other cases, including ContinueOnError.
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return false
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}
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for _, mf := range mfs {
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if err := enc.Encode(mf); err != nil {
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lastErr = err
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if opts.ErrorLog != nil {
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opts.ErrorLog.Println("error encoding and sending metric family:", err)
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}
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errCnt.WithLabelValues("encoding").Inc()
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switch opts.ErrorHandling {
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case PanicOnError:
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panic(err)
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case ContinueOnError:
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// Handled later.
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case HTTPErrorOnError:
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httpError(rsp, err)
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return
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}
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if handleError(enc.Encode(mf)) {
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||||
return
|
||||
}
|
||||
}
|
||||
if closer, ok := enc.(expfmt.Closer); ok {
|
||||
// This in particular takes care of the final "# EOF\n" line for OpenMetrics.
|
||||
if handleError(closer.Close()) {
|
||||
return
|
||||
}
|
||||
}
|
||||
|
||||
|
@ -318,6 +339,16 @@ type HandlerOpts struct {
|
|||
// away). Until the implementation is improved, it is recommended to
|
||||
// implement a separate timeout in potentially slow Collectors.
|
||||
Timeout time.Duration
|
||||
// If true, the experimental OpenMetrics encoding is added to the
|
||||
// possible options during content negotiation. Note that Prometheus
|
||||
// 2.5.0+ will negotiate OpenMetrics as first priority. OpenMetrics is
|
||||
// the only way to transmit exemplars. However, the move to OpenMetrics
|
||||
// is not completely transparent. Most notably, the values of "quantile"
|
||||
// labels of Summaries and "le" labels of Histograms are formatted with
|
||||
// a trailing ".0" if they would otherwise look like integer numbers
|
||||
// (which changes the identity of the resulting series on the Prometheus
|
||||
// server).
|
||||
EnableOpenMetrics bool
|
||||
}
|
||||
|
||||
// gzipAccepted returns whether the client will accept gzip-encoded content.
|
||||
|
|
|
@ -16,8 +16,11 @@ package prometheus
|
|||
import (
|
||||
"fmt"
|
||||
"sort"
|
||||
"time"
|
||||
"unicode/utf8"
|
||||
|
||||
"github.com/golang/protobuf/proto"
|
||||
"github.com/golang/protobuf/ptypes"
|
||||
|
||||
dto "github.com/prometheus/client_model/go"
|
||||
)
|
||||
|
@ -69,7 +72,7 @@ func (v *valueFunc) Desc() *Desc {
|
|||
}
|
||||
|
||||
func (v *valueFunc) Write(out *dto.Metric) error {
|
||||
return populateMetric(v.valType, v.function(), v.labelPairs, out)
|
||||
return populateMetric(v.valType, v.function(), v.labelPairs, nil, out)
|
||||
}
|
||||
|
||||
// NewConstMetric returns a metric with one fixed value that cannot be
|
||||
|
@ -116,19 +119,20 @@ func (m *constMetric) Desc() *Desc {
|
|||
}
|
||||
|
||||
func (m *constMetric) Write(out *dto.Metric) error {
|
||||
return populateMetric(m.valType, m.val, m.labelPairs, out)
|
||||
return populateMetric(m.valType, m.val, m.labelPairs, nil, out)
|
||||
}
|
||||
|
||||
func populateMetric(
|
||||
t ValueType,
|
||||
v float64,
|
||||
labelPairs []*dto.LabelPair,
|
||||
e *dto.Exemplar,
|
||||
m *dto.Metric,
|
||||
) error {
|
||||
m.Label = labelPairs
|
||||
switch t {
|
||||
case CounterValue:
|
||||
m.Counter = &dto.Counter{Value: proto.Float64(v)}
|
||||
m.Counter = &dto.Counter{Value: proto.Float64(v), Exemplar: e}
|
||||
case GaugeValue:
|
||||
m.Gauge = &dto.Gauge{Value: proto.Float64(v)}
|
||||
case UntypedValue:
|
||||
|
@ -160,3 +164,40 @@ func makeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair {
|
|||
sort.Sort(labelPairSorter(labelPairs))
|
||||
return labelPairs
|
||||
}
|
||||
|
||||
// ExemplarMaxRunes is the max total number of runes allowed in exemplar labels.
|
||||
const ExemplarMaxRunes = 64
|
||||
|
||||
// newExemplar creates a new dto.Exemplar from the provided values. An error is
|
||||
// returned if any of the label names or values are invalid or if the total
|
||||
// number of runes in the label names and values exceeds ExemplarMaxRunes.
|
||||
func newExemplar(value float64, ts time.Time, l Labels) (*dto.Exemplar, error) {
|
||||
e := &dto.Exemplar{}
|
||||
e.Value = proto.Float64(value)
|
||||
tsProto, err := ptypes.TimestampProto(ts)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
e.Timestamp = tsProto
|
||||
labelPairs := make([]*dto.LabelPair, 0, len(l))
|
||||
var runes int
|
||||
for name, value := range l {
|
||||
if !checkLabelName(name) {
|
||||
return nil, fmt.Errorf("exemplar label name %q is invalid", name)
|
||||
}
|
||||
runes += utf8.RuneCountInString(name)
|
||||
if !utf8.ValidString(value) {
|
||||
return nil, fmt.Errorf("exemplar label value %q is not valid UTF-8", value)
|
||||
}
|
||||
runes += utf8.RuneCountInString(value)
|
||||
labelPairs = append(labelPairs, &dto.LabelPair{
|
||||
Name: proto.String(name),
|
||||
Value: proto.String(value),
|
||||
})
|
||||
}
|
||||
if runes > ExemplarMaxRunes {
|
||||
return nil, fmt.Errorf("exemplar labels have %d runes, exceeding the limit of %d", runes, ExemplarMaxRunes)
|
||||
}
|
||||
e.Label = labelPairs
|
||||
return e, nil
|
||||
}
|
||||
|
|
Loading…
Reference in New Issue