diff options
Diffstat (limited to 'vendor/github.com/prometheus/client_golang/prometheus/gauge.go')
| -rw-r--r-- | vendor/github.com/prometheus/client_golang/prometheus/gauge.go | 204 |
1 files changed, 29 insertions, 175 deletions
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/gauge.go b/vendor/github.com/prometheus/client_golang/prometheus/gauge.go index 17c72d7eb..8b70e5141 100644 --- a/vendor/github.com/prometheus/client_golang/prometheus/gauge.go +++ b/vendor/github.com/prometheus/client_golang/prometheus/gauge.go @@ -13,14 +13,6 @@ package prometheus -import ( - "math" - "sync/atomic" - "time" - - dto "github.com/prometheus/client_model/go" -) - // Gauge is a Metric that represents a single numerical value that can // arbitrarily go up and down. // @@ -35,95 +27,29 @@ type Gauge interface { // Set sets the Gauge to an arbitrary value. Set(float64) - // Inc increments the Gauge by 1. Use Add to increment it by arbitrary - // values. + // Inc increments the Gauge by 1. Inc() - // Dec decrements the Gauge by 1. Use Sub to decrement it by arbitrary - // values. + // Dec decrements the Gauge by 1. Dec() - // Add adds the given value to the Gauge. (The value can be negative, - // resulting in a decrease of the Gauge.) + // Add adds the given value to the Gauge. (The value can be + // negative, resulting in a decrease of the Gauge.) Add(float64) // Sub subtracts the given value from the Gauge. (The value can be // negative, resulting in an increase of the Gauge.) Sub(float64) - - // SetToCurrentTime sets the Gauge to the current Unix time in seconds. - SetToCurrentTime() } // GaugeOpts is an alias for Opts. See there for doc comments. type GaugeOpts Opts // NewGauge creates a new Gauge based on the provided GaugeOpts. -// -// The returned implementation is optimized for a fast Set method. If you have a -// choice for managing the value of a Gauge via Set vs. Inc/Dec/Add/Sub, pick -// the former. For example, the Inc method of the returned Gauge is slower than -// the Inc method of a Counter returned by NewCounter. This matches the typical -// scenarios for Gauges and Counters, where the former tends to be Set-heavy and -// the latter Inc-heavy. func NewGauge(opts GaugeOpts) Gauge { - desc := NewDesc( + return newValue(NewDesc( BuildFQName(opts.Namespace, opts.Subsystem, opts.Name), opts.Help, nil, opts.ConstLabels, - ) - result := &gauge{desc: desc, labelPairs: desc.constLabelPairs} - result.init(result) // Init self-collection. - return result -} - -type gauge struct { - // valBits contains the bits of the represented float64 value. It has - // to go first in the struct to guarantee alignment for atomic - // operations. http://golang.org/pkg/sync/atomic/#pkg-note-BUG - valBits uint64 - - selfCollector - - desc *Desc - labelPairs []*dto.LabelPair -} - -func (g *gauge) Desc() *Desc { - return g.desc -} - -func (g *gauge) Set(val float64) { - atomic.StoreUint64(&g.valBits, math.Float64bits(val)) -} - -func (g *gauge) SetToCurrentTime() { - g.Set(float64(time.Now().UnixNano()) / 1e9) -} - -func (g *gauge) Inc() { - g.Add(1) -} - -func (g *gauge) Dec() { - g.Add(-1) -} - -func (g *gauge) Add(val float64) { - for { - oldBits := atomic.LoadUint64(&g.valBits) - newBits := math.Float64bits(math.Float64frombits(oldBits) + val) - if atomic.CompareAndSwapUint64(&g.valBits, oldBits, newBits) { - return - } - } -} - -func (g *gauge) Sub(val float64) { - g.Add(val * -1) -} - -func (g *gauge) Write(out *dto.Metric) error { - val := math.Float64frombits(atomic.LoadUint64(&g.valBits)) - return populateMetric(GaugeValue, val, g.labelPairs, out) + ), GaugeValue, 0) } // GaugeVec is a Collector that bundles a set of Gauges that all share the same @@ -132,11 +58,12 @@ func (g *gauge) Write(out *dto.Metric) error { // (e.g. number of operations queued, partitioned by user and operation // type). Create instances with NewGaugeVec. type GaugeVec struct { - *metricVec + *MetricVec } // NewGaugeVec creates a new GaugeVec based on the provided GaugeOpts and -// partitioned by the given label names. +// partitioned by the given label names. At least one label name must be +// provided. func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec { desc := NewDesc( BuildFQName(opts.Namespace, opts.Subsystem, opts.Name), @@ -145,62 +72,28 @@ func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec { opts.ConstLabels, ) return &GaugeVec{ - metricVec: newMetricVec(desc, func(lvs ...string) Metric { - if len(lvs) != len(desc.variableLabels) { - panic(errInconsistentCardinality) - } - result := &gauge{desc: desc, labelPairs: makeLabelPairs(desc, lvs)} - result.init(result) // Init self-collection. - return result + MetricVec: newMetricVec(desc, func(lvs ...string) Metric { + return newValue(desc, GaugeValue, 0, lvs...) }), } } -// GetMetricWithLabelValues returns the Gauge 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 Gauge is created. -// -// It is possible to call this method without using the returned Gauge to only -// create the new Gauge but leave it at its starting value 0. See also the -// SummaryVec example. -// -// Keeping the Gauge 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 Gauge from the GaugeVec. In that case, the -// Gauge will still exist, but it will not be exported anymore, even if a -// Gauge 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). -func (v *GaugeVec) GetMetricWithLabelValues(lvs ...string) (Gauge, error) { - metric, err := v.metricVec.getMetricWithLabelValues(lvs...) +// GetMetricWithLabelValues replaces the method of the same name in +// MetricVec. The difference is that this method returns a Gauge and not a +// Metric so that no type conversion is required. +func (m *GaugeVec) GetMetricWithLabelValues(lvs ...string) (Gauge, error) { + metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...) if metric != nil { return metric.(Gauge), err } return nil, err } -// GetMetricWith returns the Gauge 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 Gauge is created. Implications of -// creating a Gauge without using it and keeping the Gauge 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 *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) { - metric, err := v.metricVec.getMetricWith(labels) +// GetMetricWith replaces the method of the same name in MetricVec. The +// difference is that this method returns a Gauge and not a Metric so that no +// type conversion is required. +func (m *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) { + metric, err := m.MetricVec.GetMetricWith(labels) if metric != nil { return metric.(Gauge), err } @@ -208,57 +101,18 @@ func (v *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) { } // WithLabelValues works as GetMetricWithLabelValues, but panics where -// GetMetricWithLabelValues would have returned an error. Not returning an -// error allows shortcuts like +// GetMetricWithLabelValues would have returned an error. By not returning an +// error, WithLabelValues allows shortcuts like // myVec.WithLabelValues("404", "GET").Add(42) -func (v *GaugeVec) WithLabelValues(lvs ...string) Gauge { - g, err := v.GetMetricWithLabelValues(lvs...) - if err != nil { - panic(err) - } - return g +func (m *GaugeVec) WithLabelValues(lvs ...string) Gauge { + return m.MetricVec.WithLabelValues(lvs...).(Gauge) } // 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"}).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 +// 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) } // GaugeFunc is a Gauge whose value is determined at collect time by calling a |