diff options
Diffstat (limited to 'vendor/github.com/prometheus/client_golang/prometheus/summary.go')
| -rw-r--r-- | vendor/github.com/prometheus/client_golang/prometheus/summary.go | 173 |
1 files changed, 124 insertions, 49 deletions
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/summary.go b/vendor/github.com/prometheus/client_golang/prometheus/summary.go index bce05bf9a..f7dc85b96 100644 --- a/vendor/github.com/prometheus/client_golang/prometheus/summary.go +++ b/vendor/github.com/prometheus/client_golang/prometheus/summary.go @@ -36,7 +36,10 @@ const quantileLabel = "quantile" // // A typical use-case is the observation of request latencies. By default, a // Summary provides the median, the 90th and the 99th percentile of the latency -// as rank estimations. +// as rank estimations. However, the default behavior will change in the +// upcoming v0.10 of the library. There will be no rank estiamtions at all by +// default. For a sane transition, it is recommended to set the desired rank +// estimations explicitly. // // Note that the rank estimations cannot be aggregated in a meaningful way with // the Prometheus query language (i.e. you cannot average or add them). If you @@ -54,6 +57,9 @@ type Summary interface { } // DefObjectives are the default Summary quantile values. +// +// Deprecated: DefObjectives will not be used as the default objectives in +// v0.10 of the library. The default Summary will have no quantiles then. var ( DefObjectives = map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001} @@ -75,8 +81,10 @@ const ( ) // SummaryOpts bundles the options for creating a Summary metric. It is -// mandatory to set Name and Help to a non-empty string. All other fields are -// optional and can safely be left at their zero value. +// mandatory to set Name and Help to a non-empty string. While all other fields +// are optional and can safely be left at their zero value, it is recommended to +// explicitly set the Objectives field to the desired value as the default value +// will change in the upcoming v0.10 of the library. type SummaryOpts struct { // Namespace, Subsystem, and Name are components of the fully-qualified // name of the Summary (created by joining these components with @@ -93,29 +101,28 @@ type SummaryOpts struct { // string. Help string - // ConstLabels are used to attach fixed labels to this - // Summary. Summaries with the same fully-qualified name must have the - // same label names in their ConstLabels. - // - // Note that in most cases, labels have a value that varies during the - // lifetime of a process. Those labels are usually managed with a - // SummaryVec. ConstLabels serve only special purposes. One is for the - // special case where the value of a label does not change during the - // lifetime of a process, e.g. if the revision of the running binary is - // put into a label. Another, more advanced purpose is if more than one - // Collector needs to collect Summaries with the same fully-qualified - // name. In that case, those Summaries must differ in the values of - // their ConstLabels. See the Collector examples. + // ConstLabels are used to attach fixed labels to this metric. Metrics + // with the same fully-qualified name must have the same label names in + // their ConstLabels. // - // If the value of a label never changes (not even between binaries), - // that label most likely should not be a label at all (but part of the - // metric name). + // ConstLabels are only used rarely. In particular, do not use them to + // attach the same labels to all your metrics. Those use cases are + // better covered by target labels set by the scraping Prometheus + // server, or by one specific metric (e.g. a build_info or a + // machine_role metric). See also + // https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels,-not-static-scraped-labels ConstLabels Labels // Objectives defines the quantile rank estimates with their respective - // absolute error. If Objectives[q] = e, then the value reported - // for q will be the φ-quantile value for some φ between q-e and q+e. - // The default value is DefObjectives. + // absolute error. If Objectives[q] = e, then the value reported for q + // will be the φ-quantile value for some φ between q-e and q+e. The + // default value is DefObjectives. It is used if Objectives is left at + // its zero value (i.e. nil). To create a Summary without Objectives, + // set it to an empty map (i.e. map[float64]float64{}). + // + // Deprecated: Note that the current value of DefObjectives is + // deprecated. It will be replaced by an empty map in v0.10 of the + // library. Please explicitly set Objectives to the desired value. Objectives map[float64]float64 // MaxAge defines the duration for which an observation stays relevant @@ -183,7 +190,7 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary { } } - if len(opts.Objectives) == 0 { + if opts.Objectives == nil { opts.Objectives = DefObjectives } @@ -390,12 +397,11 @@ func (s quantSort) Less(i, j int) bool { // (e.g. HTTP request latencies, partitioned by status code and method). Create // instances with NewSummaryVec. type SummaryVec struct { - *MetricVec + *metricVec } // NewSummaryVec creates a new SummaryVec based on the provided SummaryOpts and -// partitioned by the given label names. At least one label name must be -// provided. +// partitioned by the given label names. func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec { desc := NewDesc( BuildFQName(opts.Namespace, opts.Subsystem, opts.Name), @@ -404,47 +410,116 @@ func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec { opts.ConstLabels, ) return &SummaryVec{ - MetricVec: newMetricVec(desc, func(lvs ...string) Metric { + metricVec: newMetricVec(desc, func(lvs ...string) Metric { return newSummary(desc, opts, lvs...) }), } } -// GetMetricWithLabelValues replaces the method of the same name in -// MetricVec. The difference is that this method returns a Summary and not a -// Metric so that no type conversion is required. -func (m *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Summary, error) { - metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...) +// GetMetricWithLabelValues returns the Summary for the given slice of label +// values (same order as the VariableLabels in Desc). If that combination of +// label values is accessed for the first time, a new Summary is created. +// +// It is possible to call this method without using the returned Summary to only +// create the new Summary but leave it at its starting value, a Summary without +// any observations. +// +// Keeping the Summary for later use is possible (and should be considered if +// performance is critical), but keep in mind that Reset, DeleteLabelValues and +// Delete can be used to delete the Summary from the SummaryVec. In that case, +// the Summary will still exist, but it will not be exported anymore, even if a +// Summary with the same label values is created later. See also the CounterVec +// example. +// +// An error is returned if the number of label values is not the same as the +// number of VariableLabels in Desc (minus any curried labels). +// +// Note that for more than one label value, this method is prone to mistakes +// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as +// an alternative to avoid that type of mistake. For higher label numbers, the +// latter has a much more readable (albeit more verbose) syntax, but it comes +// with a performance overhead (for creating and processing the Labels map). +// See also the GaugeVec example. +func (v *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) { + metric, err := v.metricVec.getMetricWithLabelValues(lvs...) if metric != nil { - return metric.(Summary), err + return metric.(Observer), err } return nil, err } -// GetMetricWith replaces the method of the same name in MetricVec. The -// difference is that this method returns a Summary and not a Metric so that no -// type conversion is required. -func (m *SummaryVec) GetMetricWith(labels Labels) (Summary, error) { - metric, err := m.MetricVec.GetMetricWith(labels) +// GetMetricWith returns the Summary for the given Labels map (the label names +// must match those of the VariableLabels in Desc). If that label map is +// accessed for the first time, a new Summary is created. Implications of +// creating a Summary without using it and keeping the Summary for later use are +// the same as for GetMetricWithLabelValues. +// +// An error is returned if the number and names of the Labels are inconsistent +// with those of the VariableLabels in Desc (minus any curried labels). +// +// This method is used for the same purpose as +// GetMetricWithLabelValues(...string). See there for pros and cons of the two +// methods. +func (v *SummaryVec) GetMetricWith(labels Labels) (Observer, error) { + metric, err := v.metricVec.getMetricWith(labels) if metric != nil { - return metric.(Summary), err + return metric.(Observer), err } return nil, err } // WithLabelValues works as GetMetricWithLabelValues, but panics where -// GetMetricWithLabelValues would have returned an error. By not returning an -// error, WithLabelValues allows shortcuts like +// GetMetricWithLabelValues would have returned an error. Not returning an +// error allows shortcuts like // myVec.WithLabelValues("404", "GET").Observe(42.21) -func (m *SummaryVec) WithLabelValues(lvs ...string) Summary { - return m.MetricVec.WithLabelValues(lvs...).(Summary) +func (v *SummaryVec) WithLabelValues(lvs ...string) Observer { + s, err := v.GetMetricWithLabelValues(lvs...) + if err != nil { + panic(err) + } + return s } // With works as GetMetricWith, but panics where GetMetricWithLabels would have -// returned an error. By not returning an error, With allows shortcuts like -// myVec.With(Labels{"code": "404", "method": "GET"}).Observe(42.21) -func (m *SummaryVec) With(labels Labels) Summary { - return m.MetricVec.With(labels).(Summary) +// returned an error. Not returning an error allows shortcuts like +// myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Observe(42.21) +func (v *SummaryVec) With(labels Labels) Observer { + s, err := v.GetMetricWith(labels) + if err != nil { + panic(err) + } + return s +} + +// CurryWith returns a vector curried with the provided labels, i.e. the +// returned vector has those labels pre-set for all labeled operations performed +// on it. The cardinality of the curried vector is reduced accordingly. The +// order of the remaining labels stays the same (just with the curried labels +// taken out of the sequence – which is relevant for the +// (GetMetric)WithLabelValues methods). It is possible to curry a curried +// vector, but only with labels not yet used for currying before. +// +// The metrics contained in the SummaryVec are shared between the curried and +// uncurried vectors. They are just accessed differently. Curried and uncurried +// vectors behave identically in terms of collection. Only one must be +// registered with a given registry (usually the uncurried version). The Reset +// method deletes all metrics, even if called on a curried vector. +func (v *SummaryVec) CurryWith(labels Labels) (ObserverVec, error) { + vec, err := v.curryWith(labels) + if vec != nil { + return &SummaryVec{vec}, err + } + return nil, err +} + +// MustCurryWith works as CurryWith but panics where CurryWith would have +// returned an error. +func (v *SummaryVec) MustCurryWith(labels Labels) ObserverVec { + vec, err := v.CurryWith(labels) + if err != nil { + panic(err) + } + return vec } type constSummary struct { @@ -505,8 +580,8 @@ func NewConstSummary( quantiles map[float64]float64, labelValues ...string, ) (Metric, error) { - if len(desc.variableLabels) != len(labelValues) { - return nil, errInconsistentCardinality + if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil { + return nil, err } return &constSummary{ desc: desc, |