metrics

Documentation

Index

• type Counter
• type Gauge
• type Histogram
• type LabelValues
  • func (lvs LabelValues) With(labelValues ...string) LabelValues
• type Space
  • func NewSpace() *Space
  • func (s *Space) Add(name string, lvs LabelValues, delta float64)
  • func (s *Space) Observe(name string, lvs LabelValues, value float64)
  • func (s *Space) Reset() *Space
  • func (s *Space) Walk(fn func(name string, lvs LabelValues, observations []float64) bool)

Types

type Counter

type Counter interface {
	With(labelValues ...string) Counter
	Add(delta float64)
}

Counter describes a metric that accumulates values monotonically. An example of a counter is the number of received HTTP requests.

type Gauge

type Gauge interface {
	With(labelValues ...string) Gauge
	Set(value float64)
	Add(delta float64)
}

Gauge describes a metric that takes specific values over time. An example of a gauge is the current depth of a job queue.

type Histogram

type Histogram interface {
	With(labelValues ...string) Histogram
	Observe(value float64)
}

Histogram describes a metric that takes repeated observations of the same kind of thing, and produces a statistical summary of those observations, typically expressed as quantiles or buckets. An example of a histogram is HTTP request latencies.

type LabelValues

type LabelValues []string

LabelValues is a type alias that provides validation on its With method. Metrics may include it as a member to help them satisfy With semantics and save some code duplication.

func (LabelValues) With

func (lvs LabelValues) With(labelValues ...string) LabelValues

With validates the input, and returns a new aggregate labelValues.

type Space

type Space struct {
	// contains filtered or unexported fields
}

Space represents an N-dimensional vector space. Each name and unique label value pair establishes a new dimension and point within that dimension. Order matters, i.e. [a=1 b=2] identifies a different timeseries than [b=2 a=1].

func NewSpace

func NewSpace() *Space

NewSpace returns an N-dimensional vector space.

func (*Space) Add

func (s *Space) Add(name string, lvs LabelValues, delta float64)

Add locates the time series identified by the name and label values in the vector space, and appends the delta to the last value in the list of observations.

func (*Space) Observe

func (s *Space) Observe(name string, lvs LabelValues, value float64)

Observe locates the time series identified by the name and label values in the vector space, and appends the value to the list of observations.

func (*Space) Reset

func (s *Space) Reset() *Space

Reset empties the current space and returns a new Space with the old contents. Reset a Space to get an immutable copy suitable for walking.

func (*Space) Walk

func (s *Space) Walk(fn func(name string, lvs LabelValues, observations []float64) bool)

Walk traverses the vector space and invokes fn for each non-empty time series which is encountered. Return false to abort the traversal.