/
value.go
129 lines (109 loc) · 3.46 KB
/
value.go
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// Copyright (c) 2017 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package pally
import (
"sync"
"github.com/prometheus/client_golang/prometheus"
promproto "github.com/prometheus/client_model/go"
"github.com/uber-go/tally"
"go.uber.org/atomic"
)
const _defaultVectorSize = 100
// Value is an atomic with some associated metadata. It's a building block
// for higher-level metric types.
type value struct {
atomic.Int64
opts Opts
desc *prometheus.Desc
variableLabelVals []string
labelPairs []*promproto.LabelPair
}
func newValue(opts Opts) value {
return value{
opts: opts,
desc: opts.describe(),
labelPairs: opts.labelPairs(nil /* variable label vals */),
}
}
// Desc implements half of prometheus.Metric.
func (v value) Desc() *prometheus.Desc {
return v.desc
}
// Describe implements half of prometheus.Collector.
func (v value) Describe(ch chan<- *prometheus.Desc) {
ch <- v.desc
}
// A vector is a collection of values that share the same metadata.
type vector struct {
opts Opts
desc *prometheus.Desc
// The factory function creates a new metric given the vector's metadata
// and values for the variable labels.
factory func(Opts, *prometheus.Desc, []string) metric
metricsMu sync.RWMutex
metrics map[string]metric
}
func (vec *vector) getOrCreate(labels ...string) (metric, error) {
digester := newDigester()
for _, s := range labels {
digester.add(ScrubLabelValue(s))
}
vec.metricsMu.RLock()
m, ok := vec.metrics[string(digester.digest())]
vec.metricsMu.RUnlock()
if ok {
digester.free()
return m, nil
}
vec.metricsMu.Lock()
m, err := vec.newValue(digester.digest(), labels)
vec.metricsMu.Unlock()
digester.free()
return m, err
}
func (vec *vector) newValue(key []byte, variableLabelVals []string) (metric, error) {
m, ok := vec.metrics[string(key)]
if ok {
return m, nil
}
if len(vec.opts.VariableLabels) != len(variableLabelVals) {
return nil, errInconsistentCardinality
}
m = vec.factory(vec.opts, vec.desc, variableLabelVals)
vec.metrics[string(key)] = m
return m, nil
}
func (vec *vector) Describe(ch chan<- *prometheus.Desc) {
ch <- vec.desc
}
func (vec *vector) Collect(ch chan<- prometheus.Metric) {
vec.metricsMu.RLock()
for _, m := range vec.metrics {
m.Collect(ch)
}
vec.metricsMu.RUnlock()
}
func (vec *vector) push(scope tally.Scope) {
vec.metricsMu.RLock()
for _, m := range vec.metrics {
m.push(scope)
}
vec.metricsMu.RUnlock()
}