statsd_exporter/pkg/mapper/mapper_cache.go

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// Copyright 2019 The Prometheus 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 mapper
import (
"sync"
lru "github.com/hashicorp/golang-lru"
"github.com/prometheus/client_golang/prometheus"
)
type CacheMetrics struct {
CacheLength prometheus.Gauge
CacheGetsTotal prometheus.Counter
CacheHitsTotal prometheus.Counter
}
func NewCacheMetrics(reg prometheus.Registerer) *CacheMetrics {
var m CacheMetrics
m.CacheLength = prometheus.NewGauge(
prometheus.GaugeOpts{
Name: "statsd_metric_mapper_cache_length",
Help: "The count of unique metrics currently cached.",
},
)
m.CacheGetsTotal = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "statsd_metric_mapper_cache_gets_total",
Help: "The count of total metric cache gets.",
},
)
m.CacheHitsTotal = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "statsd_metric_mapper_cache_hits_total",
Help: "The count of total metric cache hits.",
},
)
if reg != nil {
reg.MustRegister(m.CacheLength)
reg.MustRegister(m.CacheGetsTotal)
reg.MustRegister(m.CacheHitsTotal)
}
return &m
}
type cacheOptions struct {
cacheType string
}
type CacheOption func(*cacheOptions)
func WithCacheType(cacheType string) CacheOption {
return func(o *cacheOptions) {
o.cacheType = cacheType
}
}
type MetricMapperCacheResult struct {
Mapping *MetricMapping
Matched bool
Labels prometheus.Labels
}
type MetricMapperCache interface {
Get(metricString string, metricType MetricType) (*MetricMapperCacheResult, bool)
AddMatch(metricString string, metricType MetricType, mapping *MetricMapping, labels prometheus.Labels)
AddMiss(metricString string, metricType MetricType)
}
type MetricMapperLRUCache struct {
MetricMapperCache
cache *lru.Cache
metrics *CacheMetrics
}
type MetricMapperNoopCache struct {
MetricMapperCache
metrics *CacheMetrics
}
func NewMetricMapperCache(reg prometheus.Registerer, size int) (*MetricMapperLRUCache, error) {
metrics := NewCacheMetrics(reg)
cache, err := lru.New(size)
if err != nil {
return &MetricMapperLRUCache{}, err
}
return &MetricMapperLRUCache{metrics: metrics, cache: cache}, nil
}
func (m *MetricMapperLRUCache) Get(metricString string, metricType MetricType) (*MetricMapperCacheResult, bool) {
m.metrics.CacheGetsTotal.Inc()
if result, ok := m.cache.Get(formatKey(metricString, metricType)); ok {
m.metrics.CacheHitsTotal.Inc()
return result.(*MetricMapperCacheResult), true
} else {
return nil, false
}
}
func (m *MetricMapperLRUCache) AddMatch(metricString string, metricType MetricType, mapping *MetricMapping, labels prometheus.Labels) {
go m.trackCacheLength()
m.cache.Add(formatKey(metricString, metricType), &MetricMapperCacheResult{Mapping: mapping, Matched: true, Labels: labels})
}
func (m *MetricMapperLRUCache) AddMiss(metricString string, metricType MetricType) {
go m.trackCacheLength()
m.cache.Add(formatKey(metricString, metricType), &MetricMapperCacheResult{Matched: false})
}
func (m *MetricMapperLRUCache) trackCacheLength() {
m.metrics.CacheLength.Set(float64(m.cache.Len()))
}
func formatKey(metricString string, metricType MetricType) string {
return string(metricType) + "." + metricString
}
func NewMetricMapperNoopCache(reg prometheus.Registerer) *MetricMapperNoopCache {
return &MetricMapperNoopCache{metrics: NewCacheMetrics(reg)}
}
func (m *MetricMapperNoopCache) Get(metricString string, metricType MetricType) (*MetricMapperCacheResult, bool) {
return nil, false
}
func (m *MetricMapperNoopCache) AddMatch(metricString string, metricType MetricType, mapping *MetricMapping, labels prometheus.Labels) {
return
}
func (m *MetricMapperNoopCache) AddMiss(metricString string, metricType MetricType) {
return
}
type MetricMapperRRCache struct {
MetricMapperCache
lock sync.RWMutex
size int
items map[string]*MetricMapperCacheResult
metrics *CacheMetrics
}
func NewMetricMapperRRCache(reg prometheus.Registerer, size int) (*MetricMapperRRCache, error) {
metrics := NewCacheMetrics(reg)
c := &MetricMapperRRCache{
items: make(map[string]*MetricMapperCacheResult, size+1),
size: size,
metrics: metrics,
}
return c, nil
}
func (m *MetricMapperRRCache) Get(metricString string, metricType MetricType) (*MetricMapperCacheResult, bool) {
key := formatKey(metricString, metricType)
m.lock.RLock()
result, ok := m.items[key]
m.lock.RUnlock()
return result, ok
}
func (m *MetricMapperRRCache) addItem(metricString string, metricType MetricType, result *MetricMapperCacheResult) {
go m.trackCacheLength()
key := formatKey(metricString, metricType)
m.lock.Lock()
m.items[key] = result
// evict an item if needed
if len(m.items) > m.size {
for k := range m.items {
delete(m.items, k)
break
}
}
m.lock.Unlock()
}
func (m *MetricMapperRRCache) AddMatch(metricString string, metricType MetricType, mapping *MetricMapping, labels prometheus.Labels) {
e := &MetricMapperCacheResult{Mapping: mapping, Matched: true, Labels: labels}
m.addItem(metricString, metricType, e)
}
func (m *MetricMapperRRCache) AddMiss(metricString string, metricType MetricType) {
e := &MetricMapperCacheResult{Matched: false}
m.addItem(metricString, metricType, e)
}
func (m *MetricMapperRRCache) trackCacheLength() {
m.lock.RLock()
length := len(m.items)
m.lock.RUnlock()
m.metrics.CacheLength.Set(float64(length))
}