diff --git a/prometheus/counter.go b/prometheus/counter.go index 273db5f..02ea9a6 100644 --- a/prometheus/counter.go +++ b/prometheus/counter.go @@ -111,7 +111,7 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec { // Counter with the same label values is created later. // // An error is returned if the number of label values is not the same as the -// number of VariableLabels in Desc. +// 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 @@ -119,8 +119,8 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec { // 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 (m *CounterVec) GetMetricWithLabelValues(lvs ...string) (Counter, error) { - metric, err := m.metricVec.getMetricWithLabelValues(lvs...) +func (v *CounterVec) GetMetricWithLabelValues(lvs ...string) (Counter, error) { + metric, err := v.metricVec.getMetricWithLabelValues(lvs...) if metric != nil { return metric.(Counter), err } @@ -134,13 +134,13 @@ func (m *CounterVec) GetMetricWithLabelValues(lvs ...string) (Counter, error) { // 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. +// 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 (m *CounterVec) GetMetricWith(labels Labels) (Counter, error) { - metric, err := m.metricVec.getMetricWith(labels) +func (v *CounterVec) GetMetricWith(labels Labels) (Counter, error) { + metric, err := v.metricVec.getMetricWith(labels) if metric != nil { return metric.(Counter), err } @@ -148,18 +148,57 @@ func (m *CounterVec) GetMetricWith(labels Labels) (Counter, error) { } // 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").Add(42) -func (m *CounterVec) WithLabelValues(lvs ...string) Counter { - return m.metricVec.withLabelValues(lvs...).(Counter) +func (v *CounterVec) WithLabelValues(lvs ...string) Counter { + c, err := v.GetMetricWithLabelValues(lvs...) + if err != nil { + panic(err) + } + return c } // 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"}).Add(42) -func (m *CounterVec) With(labels Labels) Counter { - return m.metricVec.with(labels).(Counter) +// returned an error. Not returning an error allows shortcuts like +// myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Add(42) +func (v *CounterVec) With(labels Labels) Counter { + c, err := v.GetMetricWith(labels) + if err != nil { + panic(err) + } + return c +} + +// 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 CounterVec 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 *CounterVec) CurryWith(labels Labels) (*CounterVec, error) { + vec, err := v.curryWith(labels) + if vec != nil { + return &CounterVec{vec}, err + } + return nil, err +} + +// MustCurryWith works as CurryWith but panics where CurryWith would have +// returned an error. +func (v *CounterVec) MustCurryWith(labels Labels) *CounterVec { + vec, err := v.CurryWith(labels) + if err != nil { + panic(err) + } + return vec } // CounterFunc is a Counter whose value is determined at collect time by calling a diff --git a/prometheus/desc.go b/prometheus/desc.go index 920abc9..4a755b0 100644 --- a/prometheus/desc.go +++ b/prometheus/desc.go @@ -73,8 +73,7 @@ type Desc struct { // and therefore not part of the Desc. (They are managed within the Metric.) // // For constLabels, the label values are constant. Therefore, they are fully -// specified in the Desc. See the Opts documentation for the implications of -// constant labels. +// specified in the Desc. See the Collector example for a usage pattern. func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *Desc { d := &Desc{ fqName: fqName, diff --git a/prometheus/gauge.go b/prometheus/gauge.go index 13064da..b47d70a 100644 --- a/prometheus/gauge.go +++ b/prometheus/gauge.go @@ -98,15 +98,15 @@ func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec { // example. // // An error is returned if the number of label values is not the same as the -// number of VariableLabels in Desc. +// 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). -func (m *GaugeVec) GetMetricWithLabelValues(lvs ...string) (Gauge, error) { - metric, err := m.metricVec.getMetricWithLabelValues(lvs...) +func (v *GaugeVec) GetMetricWithLabelValues(lvs ...string) (Gauge, error) { + metric, err := v.metricVec.getMetricWithLabelValues(lvs...) if metric != nil { return metric.(Gauge), err } @@ -120,13 +120,13 @@ func (m *GaugeVec) GetMetricWithLabelValues(lvs ...string) (Gauge, error) { // 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. +// 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 (m *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) { - metric, err := m.metricVec.getMetricWith(labels) +func (v *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) { + metric, err := v.metricVec.getMetricWith(labels) if metric != nil { return metric.(Gauge), err } @@ -134,18 +134,57 @@ func (m *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) { } // 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").Add(42) -func (m *GaugeVec) WithLabelValues(lvs ...string) Gauge { - return m.metricVec.withLabelValues(lvs...).(Gauge) +func (v *GaugeVec) WithLabelValues(lvs ...string) Gauge { + g, err := v.GetMetricWithLabelValues(lvs...) + if err != nil { + panic(err) + } + return g } // 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"}).Add(42) -func (m *GaugeVec) With(labels Labels) Gauge { - return m.metricVec.with(labels).(Gauge) +// returned an error. Not returning an error allows shortcuts like +// myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Add(42) +func (v *GaugeVec) With(labels Labels) Gauge { + g, err := v.GetMetricWith(labels) + if err != nil { + panic(err) + } + return g +} + +// 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 GaugeVec 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 *GaugeVec) CurryWith(labels Labels) (*GaugeVec, error) { + vec, err := v.curryWith(labels) + if vec != nil { + return &GaugeVec{vec}, err + } + return nil, err +} + +// MustCurryWith works as CurryWith but panics where CurryWith would have +// returned an error. +func (v *GaugeVec) MustCurryWith(labels Labels) *GaugeVec { + vec, err := v.CurryWith(labels) + if err != nil { + panic(err) + } + return vec } // GaugeFunc is a Gauge whose value is determined at collect time by calling a diff --git a/prometheus/histogram.go b/prometheus/histogram.go index 6cc6e68..331783a 100644 --- a/prometheus/histogram.go +++ b/prometheus/histogram.go @@ -126,23 +126,16 @@ type HistogramOpts struct { // string. Help string - // ConstLabels are used to attach fixed labels to this - // Histogram. Histograms with the same fully-qualified name must have the - // same label names in their ConstLabels. + // 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. // - // Note that in most cases, labels have a value that varies during the - // lifetime of a process. Those labels are usually managed with a - // HistogramVec. 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 Histograms with the same fully-qualified - // name. In that case, those Summaries must differ in the values of - // their ConstLabels. See the Collector examples. - // - // 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 // Buckets defines the buckets into which observations are counted. Each @@ -322,7 +315,7 @@ func NewHistogramVec(opts HistogramOpts, labelNames []string) *HistogramVec { // example. // // An error is returned if the number of label values is not the same as the -// number of VariableLabels in Desc. +// 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 @@ -330,8 +323,8 @@ func NewHistogramVec(opts HistogramOpts, labelNames []string) *HistogramVec { // 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 (m *HistogramVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) { - metric, err := m.metricVec.getMetricWithLabelValues(lvs...) +func (v *HistogramVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) { + metric, err := v.metricVec.getMetricWithLabelValues(lvs...) if metric != nil { return metric.(Observer), err } @@ -345,13 +338,13 @@ func (m *HistogramVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) // 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. +// 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 (m *HistogramVec) GetMetricWith(labels Labels) (Observer, error) { - metric, err := m.metricVec.getMetricWith(labels) +func (v *HistogramVec) GetMetricWith(labels Labels) (Observer, error) { + metric, err := v.metricVec.getMetricWith(labels) if metric != nil { return metric.(Observer), err } @@ -359,18 +352,57 @@ func (m *HistogramVec) GetMetricWith(labels Labels) (Observer, error) { } // 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 *HistogramVec) WithLabelValues(lvs ...string) Observer { - return m.metricVec.withLabelValues(lvs...).(Observer) +func (v *HistogramVec) WithLabelValues(lvs ...string) Observer { + h, err := v.GetMetricWithLabelValues(lvs...) + if err != nil { + panic(err) + } + return h } -// 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 *HistogramVec) With(labels Labels) Observer { - return m.metricVec.with(labels).(Observer) +// With works as GetMetricWith but panics where GetMetricWithLabels would have +// returned an error. Not returning an error allows shortcuts like +// myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Observe(42.21) +func (v *HistogramVec) With(labels Labels) Observer { + h, err := v.GetMetricWith(labels) + if err != nil { + panic(err) + } + return h +} + +// 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 HistogramVec 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 *HistogramVec) CurryWith(labels Labels) (ObserverVec, error) { + vec, err := v.curryWith(labels) + if vec != nil { + return &HistogramVec{vec}, err + } + return nil, err +} + +// MustCurryWith works as CurryWith but panics where CurryWith would have +// returned an error. +func (v *HistogramVec) MustCurryWith(labels Labels) ObserverVec { + vec, err := v.CurryWith(labels) + if err != nil { + panic(err) + } + return vec } type constHistogram struct { diff --git a/prometheus/http_test.go b/prometheus/http_test.go index 7fd4077..0c7fa23 100644 --- a/prometheus/http_test.go +++ b/prometheus/http_test.go @@ -128,7 +128,7 @@ func TestInstrumentHandler(t *testing.T) { } out.Reset() - if want, got := 1, len(reqCnt.children); want != got { + if want, got := 1, len(reqCnt.metricMap.metrics); want != got { t.Errorf("want %d children in reqCnt, got %d", want, got) } cnt, err := reqCnt.GetMetricWithLabelValues("get", "418") diff --git a/prometheus/metric.go b/prometheus/metric.go index d4063d9..6213ee8 100644 --- a/prometheus/metric.go +++ b/prometheus/metric.go @@ -79,20 +79,12 @@ type Opts struct { // 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 metric - // vector collector (like CounterVec, GaugeVec, UntypedVec). 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 Metrics with the same fully-qualified name. In that - // case, those Metrics must differ in the values of their - // ConstLabels. See the Collector examples. - // - // 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 } diff --git a/prometheus/observer.go b/prometheus/observer.go index b0520e8..5806cd0 100644 --- a/prometheus/observer.go +++ b/prometheus/observer.go @@ -45,6 +45,8 @@ type ObserverVec interface { GetMetricWithLabelValues(lvs ...string) (Observer, error) With(Labels) Observer WithLabelValues(...string) Observer + CurryWith(Labels) (ObserverVec, error) + MustCurryWith(Labels) ObserverVec Collector } diff --git a/prometheus/promhttp/instrument_client.go b/prometheus/promhttp/instrument_client.go index 65f9425..91e2a5f 100644 --- a/prometheus/promhttp/instrument_client.go +++ b/prometheus/promhttp/instrument_client.go @@ -45,12 +45,11 @@ func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripp // InstrumentRoundTripperCounter is a middleware that wraps the provided // http.RoundTripper to observe the request result with the provided CounterVec. -// The CounterVec must have zero, one, or two labels. The only allowed label -// names are "code" and "method". The function panics if any other instance -// labels are provided. Partitioning of the CounterVec happens by HTTP status -// code and/or HTTP method if the respective instance label names are present -// in the CounterVec. For unpartitioned counting, use a CounterVec with -// zero labels. +// The CounterVec must have zero, one, or two non-const non-curried labels. For +// those, the only allowed label names are "code" and "method". The function +// panics otherwise. Partitioning of the CounterVec happens by HTTP status code +// and/or HTTP method if the respective instance label names are present in the +// CounterVec. For unpartitioned counting, use a CounterVec with zero labels. // // If the wrapped RoundTripper panics or returns a non-nil error, the Counter // is not incremented. diff --git a/prometheus/promhttp/instrument_server.go b/prometheus/promhttp/instrument_server.go index 3d145ad..9db2438 100644 --- a/prometheus/promhttp/instrument_server.go +++ b/prometheus/promhttp/instrument_server.go @@ -14,6 +14,7 @@ package promhttp import ( + "errors" "net/http" "strconv" "strings" @@ -42,10 +43,10 @@ func InstrumentHandlerInFlight(g prometheus.Gauge, next http.Handler) http.Handl // InstrumentHandlerDuration is a middleware that wraps the provided // http.Handler to observe the request duration with the provided ObserverVec. -// The ObserverVec must have zero, one, or two labels. The only allowed label -// names are "code" and "method". The function panics if any other instance -// labels are provided. The Observe method of the Observer in the ObserverVec -// is called with the request duration in seconds. Partitioning happens by HTTP +// The ObserverVec must have zero, one, or two non-const non-curried labels. For +// those, the only allowed label names are "code" and "method". The function +// panics otherwise. The Observe method of the Observer in the ObserverVec is +// called with the request duration in seconds. Partitioning happens by HTTP // status code and/or HTTP method if the respective instance label names are // present in the ObserverVec. For unpartitioned observations, use an // ObserverVec with zero labels. Note that partitioning of Histograms is @@ -77,14 +78,13 @@ func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler) ht }) } -// InstrumentHandlerCounter is a middleware that wraps the provided -// http.Handler to observe the request result with the provided CounterVec. -// The CounterVec must have zero, one, or two labels. The only allowed label -// names are "code" and "method". The function panics if any other instance -// labels are provided. Partitioning of the CounterVec happens by HTTP status -// code and/or HTTP method if the respective instance label names are present -// in the CounterVec. For unpartitioned counting, use a CounterVec with -// zero labels. +// InstrumentHandlerCounter is a middleware that wraps the provided http.Handler +// to observe the request result with the provided CounterVec. The CounterVec +// must have zero, one, or two non-const non-curried labels. For those, the only +// allowed label names are "code" and "method". The function panics +// otherwise. Partitioning of the CounterVec happens by HTTP status code and/or +// HTTP method if the respective instance label names are present in the +// CounterVec. For unpartitioned counting, use a CounterVec with zero labels. // // If the wrapped Handler does not set a status code, a status code of 200 is assumed. // @@ -111,14 +111,13 @@ func InstrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler) // InstrumentHandlerTimeToWriteHeader is a middleware that wraps the provided // http.Handler to observe with the provided ObserverVec the request duration // until the response headers are written. The ObserverVec must have zero, one, -// or two labels. The only allowed label names are "code" and "method". The -// function panics if any other instance labels are provided. The Observe -// method of the Observer in the ObserverVec is called with the request -// duration in seconds. Partitioning happens by HTTP status code and/or HTTP -// method if the respective instance label names are present in the -// ObserverVec. For unpartitioned observations, use an ObserverVec with zero -// labels. Note that partitioning of Histograms is expensive and should be used -// judiciously. +// or two non-const non-curried labels. For those, the only allowed label names +// are "code" and "method". The function panics otherwise. The Observe method of +// the Observer in the ObserverVec is called with the request duration in +// seconds. Partitioning happens by HTTP status code and/or HTTP method if the +// respective instance label names are present in the ObserverVec. For +// unpartitioned observations, use an ObserverVec with zero labels. Note that +// partitioning of Histograms is expensive and should be used judiciously. // // If the wrapped Handler panics before calling WriteHeader, no value is // reported. @@ -140,15 +139,15 @@ func InstrumentHandlerTimeToWriteHeader(obs prometheus.ObserverVec, next http.Ha } // InstrumentHandlerRequestSize is a middleware that wraps the provided -// http.Handler to observe the request size with the provided ObserverVec. -// The ObserverVec must have zero, one, or two labels. The only allowed label -// names are "code" and "method". The function panics if any other instance -// labels are provided. The Observe method of the Observer in the ObserverVec -// is called with the request size in bytes. Partitioning happens by HTTP -// status code and/or HTTP method if the respective instance label names are -// present in the ObserverVec. For unpartitioned observations, use an -// ObserverVec with zero labels. Note that partitioning of Histograms is -// expensive and should be used judiciously. +// http.Handler to observe the request size with the provided ObserverVec. The +// ObserverVec must have zero, one, or two non-const non-curried labels. For +// those, the only allowed label names are "code" and "method". The function +// panics otherwise. The Observe method of the Observer in the ObserverVec is +// called with the request size in bytes. Partitioning happens by HTTP status +// code and/or HTTP method if the respective instance label names are present in +// the ObserverVec. For unpartitioned observations, use an ObserverVec with zero +// labels. Note that partitioning of Histograms is expensive and should be used +// judiciously. // // If the wrapped Handler does not set a status code, a status code of 200 is assumed. // @@ -175,15 +174,15 @@ func InstrumentHandlerRequestSize(obs prometheus.ObserverVec, next http.Handler) } // InstrumentHandlerResponseSize is a middleware that wraps the provided -// http.Handler to observe the response size with the provided ObserverVec. -// The ObserverVec must have zero, one, or two labels. The only allowed label -// names are "code" and "method". The function panics if any other instance -// labels are provided. The Observe method of the Observer in the ObserverVec -// is called with the response size in bytes. Partitioning happens by HTTP -// status code and/or HTTP method if the respective instance label names are -// present in the ObserverVec. For unpartitioned observations, use an -// ObserverVec with zero labels. Note that partitioning of Histograms is -// expensive and should be used judiciously. +// http.Handler to observe the response size with the provided ObserverVec. The +// ObserverVec must have zero, one, or two non-const non-curried labels. For +// those, the only allowed label names are "code" and "method". The function +// panics otherwise. The Observe method of the Observer in the ObserverVec is +// called with the response size in bytes. Partitioning happens by HTTP status +// code and/or HTTP method if the respective instance label names are present in +// the ObserverVec. For unpartitioned observations, use an ObserverVec with zero +// labels. Note that partitioning of Histograms is expensive and should be used +// judiciously. // // If the wrapped Handler does not set a status code, a status code of 200 is assumed. // @@ -204,9 +203,12 @@ func checkLabels(c prometheus.Collector) (code bool, method bool) { // once Descriptors can have their dimensionality queried. var ( desc *prometheus.Desc + m prometheus.Metric pm dto.Metric + lvs []string ) + // Get the Desc from the Collector. descc := make(chan *prometheus.Desc, 1) c.Describe(descc) @@ -223,49 +225,54 @@ func checkLabels(c prometheus.Collector) (code bool, method bool) { close(descc) - if _, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0); err == nil { - return + // Create a ConstMetric with the Desc. Since we don't know how many + // variable labels there are, try for as long as it needs. + for err := errors.New("dummy"); err != nil; lvs = append(lvs, magicString) { + m, err = prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, lvs...) } - if m, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, magicString); err == nil { - if err := m.Write(&pm); err != nil { - panic("error checking metric for labels") - } - for _, label := range pm.Label { - name, value := label.GetName(), label.GetValue() - if value != magicString { - continue - } - switch name { - case "code": - code = true - case "method": - method = true - default: - panic("metric partitioned with non-supported labels") - } - return - } - panic("previously set label not found – this must never happen") + + // Write out the metric into a proto message and look at the labels. + // If the value is not the magicString, it is a constLabel, which doesn't interest us. + // If the label is curried, it doesn't interest us. + // In all other cases, only "code" or "method" is allowed. + if err := m.Write(&pm); err != nil { + panic("error checking metric for labels") } - if m, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, magicString, magicString); err == nil { - if err := m.Write(&pm); err != nil { - panic("error checking metric for labels") + for _, label := range pm.Label { + name, value := label.GetName(), label.GetValue() + if value != magicString || isLabelCurried(c, name) { + continue } - for _, label := range pm.Label { - name, value := label.GetName(), label.GetValue() - if value != magicString { - continue - } - if name == "code" || name == "method" { - continue - } + switch name { + case "code": + code = true + case "method": + method = true + default: panic("metric partitioned with non-supported labels") } - code = true - method = true - return } - panic("metric partitioned with non-supported labels") + return +} + +func isLabelCurried(c prometheus.Collector, label string) bool { + // This is even hackier than the label test above. + // We essentially try to curry again and see if it works. + // But for that, we need to type-convert to the two + // types we use here, ObserverVec or *CounterVec. + switch v := c.(type) { + case *prometheus.CounterVec: + if _, err := v.CurryWith(prometheus.Labels{label: "dummy"}); err == nil { + return false + } + case prometheus.ObserverVec: + if _, err := v.CurryWith(prometheus.Labels{label: "dummy"}); err == nil { + return false + } + default: + panic("unsupported metric vec type") + } + return true } // emptyLabels is a one-time allocation for non-partitioned metrics to avoid diff --git a/prometheus/promhttp/instrument_server_test.go b/prometheus/promhttp/instrument_server_test.go index 50f7524..e9af63e 100644 --- a/prometheus/promhttp/instrument_server_test.go +++ b/prometheus/promhttp/instrument_server_test.go @@ -23,6 +23,162 @@ import ( "github.com/prometheus/client_golang/prometheus" ) +func TestLabelCheck(t *testing.T) { + scenarios := map[string]struct { + varLabels []string + constLabels []string + curriedLabels []string + ok bool + }{ + "empty": { + varLabels: []string{}, + constLabels: []string{}, + curriedLabels: []string{}, + ok: true, + }, + "code as single var label": { + varLabels: []string{"code"}, + constLabels: []string{}, + curriedLabels: []string{}, + ok: true, + }, + "method as single var label": { + varLabels: []string{"method"}, + constLabels: []string{}, + curriedLabels: []string{}, + ok: true, + }, + "cade and method as var labels": { + varLabels: []string{"method", "code"}, + constLabels: []string{}, + curriedLabels: []string{}, + ok: true, + }, + "valid case with all labels used": { + varLabels: []string{"code", "method"}, + constLabels: []string{"foo", "bar"}, + curriedLabels: []string{"dings", "bums"}, + ok: true, + }, + "unsupported var label": { + varLabels: []string{"foo"}, + constLabels: []string{}, + curriedLabels: []string{}, + ok: false, + }, + "mixed var labels": { + varLabels: []string{"method", "foo", "code"}, + constLabels: []string{}, + curriedLabels: []string{}, + ok: false, + }, + "unsupported var label but curried": { + varLabels: []string{}, + constLabels: []string{}, + curriedLabels: []string{"foo"}, + ok: true, + }, + "mixed var labels but unsupported curried": { + varLabels: []string{"code", "method"}, + constLabels: []string{}, + curriedLabels: []string{"foo"}, + ok: true, + }, + "supported label as const and curry": { + varLabels: []string{}, + constLabels: []string{"code"}, + curriedLabels: []string{"method"}, + ok: true, + }, + "supported label as const and curry with unsupported as var": { + varLabels: []string{"foo"}, + constLabels: []string{"code"}, + curriedLabels: []string{"method"}, + ok: false, + }, + } + + for name, sc := range scenarios { + t.Run(name, func(t *testing.T) { + constLabels := prometheus.Labels{} + for _, l := range sc.constLabels { + constLabels[l] = "dummy" + } + c := prometheus.NewCounterVec( + prometheus.CounterOpts{ + Name: "c", + Help: "c help", + ConstLabels: constLabels, + }, + append(sc.varLabels, sc.curriedLabels...), + ) + o := prometheus.ObserverVec(prometheus.NewHistogramVec( + prometheus.HistogramOpts{ + Name: "c", + Help: "c help", + ConstLabels: constLabels, + }, + append(sc.varLabels, sc.curriedLabels...), + )) + for _, l := range sc.curriedLabels { + c = c.MustCurryWith(prometheus.Labels{l: "dummy"}) + o = o.MustCurryWith(prometheus.Labels{l: "dummy"}) + } + + func() { + defer func() { + if err := recover(); err != nil { + if sc.ok { + t.Error("unexpected panic:", err) + } + } else if !sc.ok { + t.Error("expected panic") + } + }() + InstrumentHandlerCounter(c, nil) + }() + func() { + defer func() { + if err := recover(); err != nil { + if sc.ok { + t.Error("unexpected panic:", err) + } + } else if !sc.ok { + t.Error("expected panic") + } + }() + InstrumentHandlerDuration(o, nil) + }() + if sc.ok { + // Test if wantCode and wantMethod were detected correctly. + var wantCode, wantMethod bool + for _, l := range sc.varLabels { + if l == "code" { + wantCode = true + } + if l == "method" { + wantMethod = true + } + } + gotCode, gotMethod := checkLabels(c) + if gotCode != wantCode { + t.Errorf("wanted code=%t for counter, got code=%t", wantCode, gotCode) + } + if gotMethod != wantMethod { + t.Errorf("wanted method=%t for counter, got method=%t", wantMethod, gotMethod) + } + gotCode, gotMethod = checkLabels(o) + if gotCode != wantCode { + t.Errorf("wanted code=%t for observer, got code=%t", wantCode, gotCode) + } + if gotMethod != wantMethod { + t.Errorf("wanted method=%t for observer, got method=%t", wantMethod, gotMethod) + } + } + }) + } +} + func TestMiddlewareAPI(t *testing.T) { reg := prometheus.NewRegistry() @@ -159,26 +315,15 @@ func ExampleInstrumentHandlerDuration() { []string{"code", "method"}, ) - // pushVec and pullVec are partitioned by the HTTP method and use custom - // buckets based on the expected request duration. ConstLabels are used - // to set a handler label to mark pushVec as tracking the durations for - // pushes and pullVec as tracking the durations for pulls. Note that - // Name, Help, and Buckets need to be the same for consistency, so we - // use the same HistogramOpts after just modifying the ConstLabels. - histogramOpts := prometheus.HistogramOpts{ - Name: "request_duration_seconds", - Help: "A histogram of latencies for requests.", - Buckets: []float64{.25, .5, 1, 2.5, 5, 10}, - ConstLabels: prometheus.Labels{"handler": "push"}, - } - pushVec := prometheus.NewHistogramVec( - histogramOpts, - []string{"method"}, - ) - histogramOpts.ConstLabels = prometheus.Labels{"handler": "pull"} - pullVec := prometheus.NewHistogramVec( - histogramOpts, - []string{"method"}, + // duration is partitioned by the HTTP method and handler. It uses custom + // buckets based on the expected request duration. + duration := prometheus.NewHistogramVec( + prometheus.HistogramOpts{ + Name: "request_duration_seconds", + Help: "A histogram of latencies for requests.", + Buckets: []float64{.25, .5, 1, 2.5, 5, 10}, + }, + []string{"handler", "method"}, ) // responseSize has no labels, making it a zero-dimensional @@ -201,23 +346,20 @@ func ExampleInstrumentHandlerDuration() { }) // Register all of the metrics in the standard registry. - prometheus.MustRegister(inFlightGauge, counter, pullVec, pushVec, responseSize) + prometheus.MustRegister(inFlightGauge, counter, duration, responseSize) - // Wrap the pushHandler with our shared middleware, but use the - // endpoint-specific pushVec with InstrumentHandlerDuration. + // Instrument the handlers with all the metrics, injecting the "handler" + // label by currying. pushChain := InstrumentHandlerInFlight(inFlightGauge, - InstrumentHandlerCounter(counter, - InstrumentHandlerDuration(pushVec, + InstrumentHandlerDuration(duration.MustCurryWith(prometheus.Labels{"handler": "push"}), + InstrumentHandlerCounter(counter, InstrumentHandlerResponseSize(responseSize, pushHandler), ), ), ) - - // Wrap the pushHandler with the shared middleware, but use the - // endpoint-specific pullVec with InstrumentHandlerDuration. pullChain := InstrumentHandlerInFlight(inFlightGauge, - InstrumentHandlerCounter(counter, - InstrumentHandlerDuration(pullVec, + InstrumentHandlerDuration(duration.MustCurryWith(prometheus.Labels{"handler": "pull"}), + InstrumentHandlerCounter(counter, InstrumentHandlerResponseSize(responseSize, pullHandler), ), ), diff --git a/prometheus/summary.go b/prometheus/summary.go index 21c031e..f7dc85b 100644 --- a/prometheus/summary.go +++ b/prometheus/summary.go @@ -101,23 +101,16 @@ 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. + // 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. // - // 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. - // - // 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 @@ -433,13 +426,13 @@ func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec { // // 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 +// 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. +// 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 @@ -447,8 +440,8 @@ func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec { // 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 (m *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) { - metric, err := m.metricVec.getMetricWithLabelValues(lvs...) +func (v *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) { + metric, err := v.metricVec.getMetricWithLabelValues(lvs...) if metric != nil { return metric.(Observer), err } @@ -462,13 +455,13 @@ func (m *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) { // 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. +// 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 (m *SummaryVec) GetMetricWith(labels Labels) (Observer, error) { - metric, err := m.metricVec.getMetricWith(labels) +func (v *SummaryVec) GetMetricWith(labels Labels) (Observer, error) { + metric, err := v.metricVec.getMetricWith(labels) if metric != nil { return metric.(Observer), err } @@ -476,18 +469,57 @@ func (m *SummaryVec) GetMetricWith(labels Labels) (Observer, error) { } // 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) Observer { - return m.metricVec.withLabelValues(lvs...).(Observer) +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) Observer { - return m.metricVec.with(labels).(Observer) +// 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 { diff --git a/prometheus/vec.go b/prometheus/vec.go index 65d13fe..cea1582 100644 --- a/prometheus/vec.go +++ b/prometheus/vec.go @@ -23,88 +23,31 @@ import ( // metricVec is a Collector to bundle metrics of the same name that differ in // their label values. metricVec is not used directly (and therefore // unexported). It is used as a building block for implementations of vectors of -// a given metric type, like GaugeVec, CounterVec, SummaryVec, HistogramVec, and -// UntypedVec. +// a given metric type, like GaugeVec, CounterVec, SummaryVec, and HistogramVec. +// It also handles label currying. It uses basicMetricVec internally. type metricVec struct { - mtx sync.RWMutex // Protects the children. - children map[uint64][]metricWithLabelValues - desc *Desc + *metricMap - newMetric func(labelValues ...string) Metric - hashAdd func(h uint64, s string) uint64 // replace hash function for testing collision handling + curry []curriedLabelValue + + // hashAdd and hashAddByte can be replaced for testing collision handling. + hashAdd func(h uint64, s string) uint64 hashAddByte func(h uint64, b byte) uint64 } // newMetricVec returns an initialized metricVec. func newMetricVec(desc *Desc, newMetric func(lvs ...string) Metric) *metricVec { return &metricVec{ - children: map[uint64][]metricWithLabelValues{}, - desc: desc, - newMetric: newMetric, + metricMap: &metricMap{ + metrics: map[uint64][]metricWithLabelValues{}, + desc: desc, + newMetric: newMetric, + }, hashAdd: hashAdd, hashAddByte: hashAddByte, } } -// metricWithLabelValues provides the metric and its label values for -// disambiguation on hash collision. -type metricWithLabelValues struct { - values []string - metric Metric -} - -// Describe implements Collector. The length of the returned slice -// is always one. -func (m *metricVec) Describe(ch chan<- *Desc) { - ch <- m.desc -} - -// Collect implements Collector. -func (m *metricVec) Collect(ch chan<- Metric) { - m.mtx.RLock() - defer m.mtx.RUnlock() - - for _, metrics := range m.children { - for _, metric := range metrics { - ch <- metric.metric - } - } -} - -func (m *metricVec) getMetricWithLabelValues(lvs ...string) (Metric, error) { - h, err := m.hashLabelValues(lvs) - if err != nil { - return nil, err - } - - return m.getOrCreateMetricWithLabelValues(h, lvs), nil -} - -func (m *metricVec) getMetricWith(labels Labels) (Metric, error) { - h, err := m.hashLabels(labels) - if err != nil { - return nil, err - } - - return m.getOrCreateMetricWithLabels(h, labels), nil -} - -func (m *metricVec) withLabelValues(lvs ...string) Metric { - metric, err := m.getMetricWithLabelValues(lvs...) - if err != nil { - panic(err) - } - return metric -} - -func (m *metricVec) with(labels Labels) Metric { - metric, err := m.getMetricWith(labels) - if err != nil { - panic(err) - } - return metric -} - // DeleteLabelValues removes the metric where the variable labels are the same // as those passed in as labels (same order as the VariableLabels in Desc). It // returns true if a metric was deleted. @@ -121,14 +64,12 @@ func (m *metricVec) with(labels Labels) Metric { // with a performance overhead (for creating and processing the Labels map). // See also the CounterVec example. func (m *metricVec) DeleteLabelValues(lvs ...string) bool { - m.mtx.Lock() - defer m.mtx.Unlock() - h, err := m.hashLabelValues(lvs) if err != nil { return false } - return m.deleteByHashWithLabelValues(h, lvs) + + return m.metricMap.deleteByHashWithLabelValues(h, lvs, m.curry) } // Delete deletes the metric where the variable labels are the same as those @@ -142,35 +83,190 @@ func (m *metricVec) DeleteLabelValues(lvs ...string) bool { // This method is used for the same purpose as DeleteLabelValues(...string). See // there for pros and cons of the two methods. func (m *metricVec) Delete(labels Labels) bool { - m.mtx.Lock() - defer m.mtx.Unlock() - h, err := m.hashLabels(labels) if err != nil { return false } - return m.deleteByHashWithLabels(h, labels) + return m.metricMap.deleteByHashWithLabels(h, labels, m.curry) +} + +func (m *metricVec) curryWith(labels Labels) (*metricVec, error) { + var ( + newCurry []curriedLabelValue + oldCurry = m.curry + iCurry int + ) + for i, label := range m.desc.variableLabels { + val, ok := labels[label] + if iCurry < len(oldCurry) && oldCurry[iCurry].index == i { + if ok { + return nil, fmt.Errorf("label name %q is already curried", label) + } + newCurry = append(newCurry, oldCurry[iCurry]) + iCurry++ + } else { + if !ok { + continue // Label stays uncurried. + } + newCurry = append(newCurry, curriedLabelValue{i, val}) + } + } + if l := len(oldCurry) + len(labels) - len(newCurry); l > 0 { + return nil, fmt.Errorf("%d unknown label(s) found during currying", l) + } + + return &metricVec{ + metricMap: m.metricMap, + curry: newCurry, + hashAdd: m.hashAdd, + hashAddByte: m.hashAddByte, + }, nil +} + +func (m *metricVec) getMetricWithLabelValues(lvs ...string) (Metric, error) { + h, err := m.hashLabelValues(lvs) + if err != nil { + return nil, err + } + + return m.metricMap.getOrCreateMetricWithLabelValues(h, lvs, m.curry), nil +} + +func (m *metricVec) getMetricWith(labels Labels) (Metric, error) { + h, err := m.hashLabels(labels) + if err != nil { + return nil, err + } + + return m.metricMap.getOrCreateMetricWithLabels(h, labels, m.curry), nil +} + +func (m *metricVec) hashLabelValues(vals []string) (uint64, error) { + if err := validateLabelValues(vals, len(m.desc.variableLabels)-len(m.curry)); err != nil { + return 0, err + } + + var ( + h = hashNew() + curry = m.curry + iVals, iCurry int + ) + for i := 0; i < len(m.desc.variableLabels); i++ { + if iCurry < len(curry) && curry[iCurry].index == i { + h = m.hashAdd(h, curry[iCurry].value) + iCurry++ + } else { + h = m.hashAdd(h, vals[iVals]) + iVals++ + } + h = m.hashAddByte(h, model.SeparatorByte) + } + return h, nil +} + +func (m *metricVec) hashLabels(labels Labels) (uint64, error) { + if err := validateValuesInLabels(labels, len(m.desc.variableLabels)-len(m.curry)); err != nil { + return 0, err + } + + var ( + h = hashNew() + curry = m.curry + iCurry int + ) + for i, label := range m.desc.variableLabels { + val, ok := labels[label] + if iCurry < len(curry) && curry[iCurry].index == i { + if ok { + return 0, fmt.Errorf("label name %q is already curried", label) + } + h = m.hashAdd(h, curry[iCurry].value) + iCurry++ + } else { + if !ok { + return 0, fmt.Errorf("label name %q missing in label map", label) + } + h = m.hashAdd(h, val) + } + h = m.hashAddByte(h, model.SeparatorByte) + } + return h, nil +} + +// metricWithLabelValues provides the metric and its label values for +// disambiguation on hash collision. +type metricWithLabelValues struct { + values []string + metric Metric +} + +// curriedLabelValue sets the curried value for a label at the given index. +type curriedLabelValue struct { + index int + value string +} + +// metricMap is a helper for metricVec and shared between differently curried +// metricVecs. +type metricMap struct { + mtx sync.RWMutex // Protects metrics. + metrics map[uint64][]metricWithLabelValues + desc *Desc + newMetric func(labelValues ...string) Metric +} + +// Describe implements Collector. It will send exactly one Desc to the provided +// channel. +func (m *metricMap) Describe(ch chan<- *Desc) { + ch <- m.desc +} + +// Collect implements Collector. +func (m *metricMap) Collect(ch chan<- Metric) { + m.mtx.RLock() + defer m.mtx.RUnlock() + + for _, metrics := range m.metrics { + for _, metric := range metrics { + ch <- metric.metric + } + } +} + +// Reset deletes all metrics in this vector. +func (m *metricMap) Reset() { + m.mtx.Lock() + defer m.mtx.Unlock() + + for h := range m.metrics { + delete(m.metrics, h) + } } // deleteByHashWithLabelValues removes the metric from the hash bucket h. If // there are multiple matches in the bucket, use lvs to select a metric and // remove only that metric. -func (m *metricVec) deleteByHashWithLabelValues(h uint64, lvs []string) bool { - metrics, ok := m.children[h] +func (m *metricMap) deleteByHashWithLabelValues( + h uint64, lvs []string, curry []curriedLabelValue, +) bool { + m.mtx.Lock() + defer m.mtx.Unlock() + + metrics, ok := m.metrics[h] if !ok { return false } - i := m.findMetricWithLabelValues(metrics, lvs) + i := findMetricWithLabelValues(metrics, lvs, curry) if i >= len(metrics) { return false } if len(metrics) > 1 { - m.children[h] = append(metrics[:i], metrics[i+1:]...) + m.metrics[h] = append(metrics[:i], metrics[i+1:]...) } else { - delete(m.children, h) + delete(m.metrics, h) } return true } @@ -178,71 +274,35 @@ func (m *metricVec) deleteByHashWithLabelValues(h uint64, lvs []string) bool { // deleteByHashWithLabels removes the metric from the hash bucket h. If there // are multiple matches in the bucket, use lvs to select a metric and remove // only that metric. -func (m *metricVec) deleteByHashWithLabels(h uint64, labels Labels) bool { - metrics, ok := m.children[h] +func (m *metricMap) deleteByHashWithLabels( + h uint64, labels Labels, curry []curriedLabelValue, +) bool { + metrics, ok := m.metrics[h] if !ok { return false } - i := m.findMetricWithLabels(metrics, labels) + i := findMetricWithLabels(m.desc, metrics, labels, curry) if i >= len(metrics) { return false } if len(metrics) > 1 { - m.children[h] = append(metrics[:i], metrics[i+1:]...) + m.metrics[h] = append(metrics[:i], metrics[i+1:]...) } else { - delete(m.children, h) + delete(m.metrics, h) } return true } -// Reset deletes all metrics in this vector. -func (m *metricVec) Reset() { - m.mtx.Lock() - defer m.mtx.Unlock() - - for h := range m.children { - delete(m.children, h) - } -} - -func (m *metricVec) hashLabelValues(vals []string) (uint64, error) { - if err := validateLabelValues(vals, len(m.desc.variableLabels)); err != nil { - return 0, err - } - - h := hashNew() - for _, val := range vals { - h = m.hashAdd(h, val) - h = m.hashAddByte(h, model.SeparatorByte) - } - return h, nil -} - -func (m *metricVec) hashLabels(labels Labels) (uint64, error) { - if err := validateValuesInLabels(labels, len(m.desc.variableLabels)); err != nil { - return 0, err - } - - h := hashNew() - for _, label := range m.desc.variableLabels { - val, ok := labels[label] - if !ok { - return 0, fmt.Errorf("label name %q missing in label map", label) - } - h = m.hashAdd(h, val) - h = m.hashAddByte(h, model.SeparatorByte) - } - return h, nil -} - // getOrCreateMetricWithLabelValues retrieves the metric by hash and label value // or creates it and returns the new one. // // This function holds the mutex. -func (m *metricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string) Metric { +func (m *metricMap) getOrCreateMetricWithLabelValues( + hash uint64, lvs []string, curry []curriedLabelValue, +) Metric { m.mtx.RLock() - metric, ok := m.getMetricWithHashAndLabelValues(hash, lvs) + metric, ok := m.getMetricWithHashAndLabelValues(hash, lvs, curry) m.mtx.RUnlock() if ok { return metric @@ -250,13 +310,11 @@ func (m *metricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string) m.mtx.Lock() defer m.mtx.Unlock() - metric, ok = m.getMetricWithHashAndLabelValues(hash, lvs) + metric, ok = m.getMetricWithHashAndLabelValues(hash, lvs, curry) if !ok { - // Copy to avoid allocation in case wo don't go down this code path. - copiedLVs := make([]string, len(lvs)) - copy(copiedLVs, lvs) - metric = m.newMetric(copiedLVs...) - m.children[hash] = append(m.children[hash], metricWithLabelValues{values: copiedLVs, metric: metric}) + inlinedLVs := inlineLabelValues(lvs, curry) + metric = m.newMetric(inlinedLVs...) + m.metrics[hash] = append(m.metrics[hash], metricWithLabelValues{values: inlinedLVs, metric: metric}) } return metric } @@ -265,9 +323,11 @@ func (m *metricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string) // or creates it and returns the new one. // // This function holds the mutex. -func (m *metricVec) getOrCreateMetricWithLabels(hash uint64, labels Labels) Metric { +func (m *metricMap) getOrCreateMetricWithLabels( + hash uint64, labels Labels, curry []curriedLabelValue, +) Metric { m.mtx.RLock() - metric, ok := m.getMetricWithHashAndLabels(hash, labels) + metric, ok := m.getMetricWithHashAndLabels(hash, labels, curry) m.mtx.RUnlock() if ok { return metric @@ -275,21 +335,23 @@ func (m *metricVec) getOrCreateMetricWithLabels(hash uint64, labels Labels) Metr m.mtx.Lock() defer m.mtx.Unlock() - metric, ok = m.getMetricWithHashAndLabels(hash, labels) + metric, ok = m.getMetricWithHashAndLabels(hash, labels, curry) if !ok { - lvs := m.extractLabelValues(labels) + lvs := extractLabelValues(m.desc, labels, curry) metric = m.newMetric(lvs...) - m.children[hash] = append(m.children[hash], metricWithLabelValues{values: lvs, metric: metric}) + m.metrics[hash] = append(m.metrics[hash], metricWithLabelValues{values: lvs, metric: metric}) } return metric } // getMetricWithHashAndLabelValues gets a metric while handling possible // collisions in the hash space. Must be called while holding the read mutex. -func (m *metricVec) getMetricWithHashAndLabelValues(h uint64, lvs []string) (Metric, bool) { - metrics, ok := m.children[h] +func (m *metricMap) getMetricWithHashAndLabelValues( + h uint64, lvs []string, curry []curriedLabelValue, +) (Metric, bool) { + metrics, ok := m.metrics[h] if ok { - if i := m.findMetricWithLabelValues(metrics, lvs); i < len(metrics) { + if i := findMetricWithLabelValues(metrics, lvs, curry); i < len(metrics) { return metrics[i].metric, true } } @@ -298,10 +360,12 @@ func (m *metricVec) getMetricWithHashAndLabelValues(h uint64, lvs []string) (Met // getMetricWithHashAndLabels gets a metric while handling possible collisions in // the hash space. Must be called while holding read mutex. -func (m *metricVec) getMetricWithHashAndLabels(h uint64, labels Labels) (Metric, bool) { - metrics, ok := m.children[h] +func (m *metricMap) getMetricWithHashAndLabels( + h uint64, labels Labels, curry []curriedLabelValue, +) (Metric, bool) { + metrics, ok := m.metrics[h] if ok { - if i := m.findMetricWithLabels(metrics, labels); i < len(metrics) { + if i := findMetricWithLabels(m.desc, metrics, labels, curry); i < len(metrics) { return metrics[i].metric, true } } @@ -310,9 +374,11 @@ func (m *metricVec) getMetricWithHashAndLabels(h uint64, labels Labels) (Metric, // findMetricWithLabelValues returns the index of the matching metric or // len(metrics) if not found. -func (m *metricVec) findMetricWithLabelValues(metrics []metricWithLabelValues, lvs []string) int { +func findMetricWithLabelValues( + metrics []metricWithLabelValues, lvs []string, curry []curriedLabelValue, +) int { for i, metric := range metrics { - if m.matchLabelValues(metric.values, lvs) { + if matchLabelValues(metric.values, lvs, curry) { return i } } @@ -321,32 +387,51 @@ func (m *metricVec) findMetricWithLabelValues(metrics []metricWithLabelValues, l // findMetricWithLabels returns the index of the matching metric or len(metrics) // if not found. -func (m *metricVec) findMetricWithLabels(metrics []metricWithLabelValues, labels Labels) int { +func findMetricWithLabels( + desc *Desc, metrics []metricWithLabelValues, labels Labels, curry []curriedLabelValue, +) int { for i, metric := range metrics { - if m.matchLabels(metric.values, labels) { + if matchLabels(desc, metric.values, labels, curry) { return i } } return len(metrics) } -func (m *metricVec) matchLabelValues(values []string, lvs []string) bool { - if len(values) != len(lvs) { +func matchLabelValues(values []string, lvs []string, curry []curriedLabelValue) bool { + if len(values) != len(lvs)+len(curry) { return false } + var iLVs, iCurry int for i, v := range values { - if v != lvs[i] { + if iCurry < len(curry) && curry[iCurry].index == i { + if v != curry[iCurry].value { + return false + } + iCurry++ + continue + } + if v != lvs[iLVs] { return false } + iLVs++ } return true } -func (m *metricVec) matchLabels(values []string, labels Labels) bool { - if len(labels) != len(values) { +func matchLabels(desc *Desc, values []string, labels Labels, curry []curriedLabelValue) bool { + if len(values) != len(labels)+len(curry) { return false } - for i, k := range m.desc.variableLabels { + iCurry := 0 + for i, k := range desc.variableLabels { + if iCurry < len(curry) && curry[iCurry].index == i { + if values[i] != curry[iCurry].value { + return false + } + iCurry++ + continue + } if values[i] != labels[k] { return false } @@ -354,10 +439,31 @@ func (m *metricVec) matchLabels(values []string, labels Labels) bool { return true } -func (m *metricVec) extractLabelValues(labels Labels) []string { - labelValues := make([]string, len(labels)) - for i, k := range m.desc.variableLabels { +func extractLabelValues(desc *Desc, labels Labels, curry []curriedLabelValue) []string { + labelValues := make([]string, len(labels)+len(curry)) + iCurry := 0 + for i, k := range desc.variableLabels { + if iCurry < len(curry) && curry[iCurry].index == i { + labelValues[i] = curry[iCurry].value + iCurry++ + continue + } labelValues[i] = labels[k] } return labelValues } + +func inlineLabelValues(lvs []string, curry []curriedLabelValue) []string { + labelValues := make([]string, len(lvs)+len(curry)) + var iCurry, iLVs int + for i := range labelValues { + if iCurry < len(curry) && curry[iCurry].index == i { + labelValues[i] = curry[iCurry].value + iCurry++ + continue + } + labelValues[i] = lvs[iLVs] + iLVs++ + } + return labelValues +} diff --git a/prometheus/vec_test.go b/prometheus/vec_test.go index f767f7a..bd18a9f 100644 --- a/prometheus/vec_test.go +++ b/prometheus/vec_test.go @@ -166,7 +166,7 @@ func testMetricVec(t *testing.T, vec *GaugeVec) { } var total int - for _, metrics := range vec.children { + for _, metrics := range vec.metricMap.metrics { for _, metric := range metrics { total++ copy(pair[:], metric.values) @@ -201,7 +201,7 @@ func testMetricVec(t *testing.T, vec *GaugeVec) { vec.Reset() - if len(vec.children) > 0 { + if len(vec.metricMap.metrics) > 0 { t.Fatalf("reset failed") } } @@ -239,6 +239,229 @@ func TestCounterVecEndToEndWithCollision(t *testing.T) { } } +func TestCurryVec(t *testing.T) { + vec := NewCounterVec( + CounterOpts{ + Name: "test", + Help: "helpless", + }, + []string{"one", "two", "three"}, + ) + testCurryVec(t, vec) +} + +func TestCurryVecWithCollisions(t *testing.T) { + vec := NewCounterVec( + CounterOpts{ + Name: "test", + Help: "helpless", + }, + []string{"one", "two", "three"}, + ) + vec.hashAdd = func(h uint64, s string) uint64 { return 1 } + vec.hashAddByte = func(h uint64, b byte) uint64 { return 1 } + testCurryVec(t, vec) +} + +func testCurryVec(t *testing.T, vec *CounterVec) { + + assertMetrics := func(t *testing.T) { + n := 0 + for _, m := range vec.metricMap.metrics { + n += len(m) + } + if n != 2 { + t.Error("expected two metrics, got", n) + } + m := &dto.Metric{} + c1, err := vec.GetMetricWithLabelValues("1", "2", "3") + if err != nil { + t.Fatal("unexpected error getting metric:", err) + } + c1.Write(m) + if want, got := 1., m.GetCounter().GetValue(); want != got { + t.Errorf("want %f as counter value, got %f", want, got) + } + m.Reset() + c2, err := vec.GetMetricWithLabelValues("11", "22", "33") + if err != nil { + t.Fatal("unexpected error getting metric:", err) + } + c2.Write(m) + if want, got := 1., m.GetCounter().GetValue(); want != got { + t.Errorf("want %f as counter value, got %f", want, got) + } + } + + assertNoMetric := func(t *testing.T) { + if n := len(vec.metricMap.metrics); n != 0 { + t.Error("expected no metrics, got", n) + } + } + + t.Run("zero labels", func(t *testing.T) { + c1 := vec.MustCurryWith(nil) + c2 := vec.MustCurryWith(nil) + c1.WithLabelValues("1", "2", "3").Inc() + c2.With(Labels{"one": "11", "two": "22", "three": "33"}).Inc() + assertMetrics(t) + if !c1.Delete(Labels{"one": "1", "two": "2", "three": "3"}) { + t.Error("deletion failed") + } + if !c2.DeleteLabelValues("11", "22", "33") { + t.Error("deletion failed") + } + assertNoMetric(t) + }) + t.Run("first label", func(t *testing.T) { + c1 := vec.MustCurryWith(Labels{"one": "1"}) + c2 := vec.MustCurryWith(Labels{"one": "11"}) + c1.WithLabelValues("2", "3").Inc() + c2.With(Labels{"two": "22", "three": "33"}).Inc() + assertMetrics(t) + if c1.Delete(Labels{"two": "22", "three": "33"}) { + t.Error("deletion unexpectedly succeeded") + } + if c2.DeleteLabelValues("2", "3") { + t.Error("deletion unexpectedly succeeded") + } + if !c1.Delete(Labels{"two": "2", "three": "3"}) { + t.Error("deletion failed") + } + if !c2.DeleteLabelValues("22", "33") { + t.Error("deletion failed") + } + assertNoMetric(t) + }) + t.Run("middle label", func(t *testing.T) { + c1 := vec.MustCurryWith(Labels{"two": "2"}) + c2 := vec.MustCurryWith(Labels{"two": "22"}) + c1.WithLabelValues("1", "3").Inc() + c2.With(Labels{"one": "11", "three": "33"}).Inc() + assertMetrics(t) + if c1.Delete(Labels{"one": "11", "three": "33"}) { + t.Error("deletion unexpectedly succeeded") + } + if c2.DeleteLabelValues("1", "3") { + t.Error("deletion unexpectedly succeeded") + } + if !c1.Delete(Labels{"one": "1", "three": "3"}) { + t.Error("deletion failed") + } + if !c2.DeleteLabelValues("11", "33") { + t.Error("deletion failed") + } + assertNoMetric(t) + }) + t.Run("last label", func(t *testing.T) { + c1 := vec.MustCurryWith(Labels{"three": "3"}) + c2 := vec.MustCurryWith(Labels{"three": "33"}) + c1.WithLabelValues("1", "2").Inc() + c2.With(Labels{"one": "11", "two": "22"}).Inc() + assertMetrics(t) + if c1.Delete(Labels{"two": "22", "one": "11"}) { + t.Error("deletion unexpectedly succeeded") + } + if c2.DeleteLabelValues("1", "2") { + t.Error("deletion unexpectedly succeeded") + } + if !c1.Delete(Labels{"two": "2", "one": "1"}) { + t.Error("deletion failed") + } + if !c2.DeleteLabelValues("11", "22") { + t.Error("deletion failed") + } + assertNoMetric(t) + }) + t.Run("two labels", func(t *testing.T) { + c1 := vec.MustCurryWith(Labels{"three": "3", "one": "1"}) + c2 := vec.MustCurryWith(Labels{"three": "33", "one": "11"}) + c1.WithLabelValues("2").Inc() + c2.With(Labels{"two": "22"}).Inc() + assertMetrics(t) + if c1.Delete(Labels{"two": "22"}) { + t.Error("deletion unexpectedly succeeded") + } + if c2.DeleteLabelValues("2") { + t.Error("deletion unexpectedly succeeded") + } + if !c1.Delete(Labels{"two": "2"}) { + t.Error("deletion failed") + } + if !c2.DeleteLabelValues("22") { + t.Error("deletion failed") + } + assertNoMetric(t) + }) + t.Run("all labels", func(t *testing.T) { + c1 := vec.MustCurryWith(Labels{"three": "3", "two": "2", "one": "1"}) + c2 := vec.MustCurryWith(Labels{"three": "33", "one": "11", "two": "22"}) + c1.WithLabelValues().Inc() + c2.With(nil).Inc() + assertMetrics(t) + if !c1.Delete(Labels{}) { + t.Error("deletion failed") + } + if !c2.DeleteLabelValues() { + t.Error("deletion failed") + } + assertNoMetric(t) + }) + t.Run("double curry", func(t *testing.T) { + c1 := vec.MustCurryWith(Labels{"three": "3"}).MustCurryWith(Labels{"one": "1"}) + c2 := vec.MustCurryWith(Labels{"three": "33"}).MustCurryWith(Labels{"one": "11"}) + c1.WithLabelValues("2").Inc() + c2.With(Labels{"two": "22"}).Inc() + assertMetrics(t) + if c1.Delete(Labels{"two": "22"}) { + t.Error("deletion unexpectedly succeeded") + } + if c2.DeleteLabelValues("2") { + t.Error("deletion unexpectedly succeeded") + } + if !c1.Delete(Labels{"two": "2"}) { + t.Error("deletion failed") + } + if !c2.DeleteLabelValues("22") { + t.Error("deletion failed") + } + assertNoMetric(t) + }) + t.Run("use already curried label", func(t *testing.T) { + c1 := vec.MustCurryWith(Labels{"three": "3"}) + if _, err := c1.GetMetricWithLabelValues("1", "2", "3"); err == nil { + t.Error("expected error when using already curried label") + } + if _, err := c1.GetMetricWith(Labels{"one": "1", "two": "2", "three": "3"}); err == nil { + t.Error("expected error when using already curried label") + } + assertNoMetric(t) + c1.WithLabelValues("1", "2").Inc() + if c1.Delete(Labels{"one": "1", "two": "2", "three": "3"}) { + t.Error("deletion unexpectedly succeeded") + } + if !c1.Delete(Labels{"one": "1", "two": "2"}) { + t.Error("deletion failed") + } + assertNoMetric(t) + }) + t.Run("curry already curried label", func(t *testing.T) { + if _, err := vec.MustCurryWith(Labels{"three": "3"}).CurryWith(Labels{"three": "33"}); err == nil { + t.Error("currying unexpectedly succeeded") + } else if err.Error() != `label name "three" is already curried` { + t.Error("currying returned unexpected error:", err) + } + + }) + t.Run("unknown label", func(t *testing.T) { + if _, err := vec.CurryWith(Labels{"foo": "bar"}); err == nil { + t.Error("currying unexpectedly succeeded") + } else if err.Error() != "1 unknown label(s) found during currying" { + t.Error("currying returned unexpected error:", err) + } + }) +} + func BenchmarkMetricVecWithLabelValuesBasic(b *testing.B) { benchmarkMetricVecWithLabelValues(b, map[string][]string{ "l1": {"onevalue"},