metric

Documentation

Overview

Package metric provides primitives for collecting metrics.

Index

• Variables
• func Disable()
• func EmitMetricUpdate()
• func Initialize()
• func MustRegisterCustomUint64Metric(name string, sync bool, description string, value func() uint64)
• func RegisterCustomUint64Metric(name string, sync bool, description string, value func() uint64) error
• type Uint64Metric
  • func MustCreateNewUint64Metric(name string, sync bool, description string) *Uint64Metric
  • func NewUint64Metric(name string, sync bool, description string) (*Uint64Metric, error)
  • func (m *Uint64Metric) Increment()
  • func (m *Uint64Metric) IncrementBy(v uint64)
  • func (m *Uint64Metric) Value() uint64

Variables

var (
	// ErrNameInUse indicates that another metric is already defined for
	// the given name.
	ErrNameInUse = errors.New("metric name already in use")

	// ErrInitializationDone indicates that the caller tried to create a
	// new metric after initialization.
	ErrInitializationDone = errors.New("metric cannot be created after initialization is complete")
)

Functions

func Disable

func Disable()

Disable sends an empty metric registration event over the event channel, disabling metric collection.

Precondition:

• All metrics are registered.
• Initialize/Disable has not been called.

func EmitMetricUpdate

func EmitMetricUpdate()

EmitMetricUpdate emits a MetricUpdate over the event channel.

Only metrics that have changed since the last call are emitted.

EmitMetricUpdate is thread-safe.

Preconditions:

• Initialize has been called.

func Initialize

func Initialize()

Initialize sends a metric registration event over the event channel.

Precondition:

• All metrics are registered.
• Initialize/Disable has not been called.

func MustRegisterCustomUint64Metric

func MustRegisterCustomUint64Metric(name string, sync bool, description string, value func() uint64)

MustRegisterCustomUint64Metric calls RegisterCustomUint64Metric and panics if it returns an error.

func RegisterCustomUint64Metric

func RegisterCustomUint64Metric(name string, sync bool, description string, value func() uint64) error

RegisterCustomUint64Metric registers a metric with the given name.

Register must only be called at init and will return and error if called after Initialized.

All metrics must be cumulative, meaning that the return values of value must only increase over time.

Preconditions:

• name must be globally unique.
• Initialize/Disable have not been called.

Types

type Uint64Metric

type Uint64Metric struct {
	// contains filtered or unexported fields
}

Uint64Metric encapsulates a uint64 that represents some kind of metric to be monitored.

All metrics must be cumulative, meaning that their values will only increase over time.

Metrics are not saved across save/restore and thus reset to zero on restore.

TODO(b/67298402): Support non-cumulative metrics. TODO(b/67298427): Support metric fields.

func MustCreateNewUint64Metric

func MustCreateNewUint64Metric(name string, sync bool, description string) *Uint64Metric

MustCreateNewUint64Metric calls NewUint64Metric and panics if it returns an error.

func NewUint64Metric

func NewUint64Metric(name string, sync bool, description string) (*Uint64Metric, error)

NewUint64Metric creates and registers a new metric with the given name.

Metrics must be statically defined (i.e., at init).

func (*Uint64Metric) Increment

func (m *Uint64Metric) Increment()

Increment increments the metric by 1.

func (*Uint64Metric) IncrementBy

func (m *Uint64Metric) IncrementBy(v uint64)

IncrementBy increments the metric by v.

func (*Uint64Metric) Value

func (m *Uint64Metric) Value() uint64

Value returns the current value of the metric.