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- // Copyright 2018, OpenCensus Authors
- //
- // Licensed under the Apache License, Version 2.0 (the "License");
- // you may not use this file except in compliance with the License.
- // You may obtain a copy of the License at
- //
- // http://www.apache.org/licenses/LICENSE-2.0
- //
- // Unless required by applicable law or agreed to in writing, software
- // distributed under the License is distributed on an "AS IS" BASIS,
- // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- // See the License for the specific language governing permissions and
- // limitations under the License.
-
- package metric
-
- import (
- "sync"
- "time"
-
- "go.opencensus.io/metric/metricdata"
- )
-
- // Registry creates and manages a set of gauges.
- // External synchronization is required if you want to add gauges to the same
- // registry from multiple goroutines.
- type Registry struct {
- gauges sync.Map
- }
-
- type gaugeType int
-
- const (
- gaugeInt64 gaugeType = iota
- gaugeFloat64
- derivedGaugeInt64
- derivedGaugeFloat64
- )
-
- // NewRegistry initializes a new Registry.
- func NewRegistry() *Registry {
- return &Registry{}
- }
-
- // AddFloat64Gauge creates and adds a new float64-valued gauge to this registry.
- func (r *Registry) AddFloat64Gauge(name, description string, unit metricdata.Unit, labelKeys ...string) (*Float64Gauge, error) {
- f := &Float64Gauge{
- g: gauge{
- gType: gaugeFloat64,
- },
- }
- _, err := r.initGauge(&f.g, labelKeys, name, description, unit)
- if err != nil {
- return nil, err
- }
- return f, nil
- }
-
- // AddInt64Gauge creates and adds a new int64-valued gauge to this registry.
- func (r *Registry) AddInt64Gauge(name, description string, unit metricdata.Unit, labelKeys ...string) (*Int64Gauge, error) {
- i := &Int64Gauge{
- g: gauge{
- gType: gaugeInt64,
- },
- }
- _, err := r.initGauge(&i.g, labelKeys, name, description, unit)
- if err != nil {
- return nil, err
- }
- return i, nil
- }
-
- // AddInt64DerivedGauge creates and adds a new derived int64-valued gauge to this registry.
- // A derived gauge is convenient form of gauge where the object associated with the gauge
- // provides its value by implementing func() int64.
- func (r *Registry) AddInt64DerivedGauge(name, description string, unit metricdata.Unit, labelKeys ...string) (*Int64DerivedGauge, error) {
- i := &Int64DerivedGauge{
- g: gauge{
- gType: derivedGaugeInt64,
- },
- }
- _, err := r.initGauge(&i.g, labelKeys, name, description, unit)
- if err != nil {
- return nil, err
- }
- return i, nil
- }
-
- // AddFloat64DerivedGauge creates and adds a new derived float64-valued gauge to this registry.
- // A derived gauge is convenient form of gauge where the object associated with the gauge
- // provides its value by implementing func() float64.
- func (r *Registry) AddFloat64DerivedGauge(name, description string, unit metricdata.Unit, labelKeys ...string) (*Float64DerivedGauge, error) {
- f := &Float64DerivedGauge{
- g: gauge{
- gType: derivedGaugeFloat64,
- },
- }
- _, err := r.initGauge(&f.g, labelKeys, name, description, unit)
- if err != nil {
- return nil, err
- }
- return f, nil
- }
-
- func (r *Registry) initGauge(g *gauge, labelKeys []string, name string, description string, unit metricdata.Unit) (*gauge, error) {
- val, ok := r.gauges.Load(name)
- if ok {
- existing := val.(*gauge)
- if existing.gType != g.gType {
- return nil, errGaugeExistsWithDiffType
- }
- }
- g.keys = labelKeys
- g.start = time.Now()
- g.desc = metricdata.Descriptor{
- Name: name,
- Description: description,
- Unit: unit,
- LabelKeys: labelKeys,
- }
- r.gauges.Store(name, g)
- return g, nil
- }
-
- // Read reads all gauges in this registry and returns their values as metrics.
- func (r *Registry) Read() []*metricdata.Metric {
- ms := []*metricdata.Metric{}
- r.gauges.Range(func(k, v interface{}) bool {
- g := v.(*gauge)
- ms = append(ms, g.read())
- return true
- })
- return ms
- }
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