statsd_exporter/pkg/mapper_cache/randomreplacement/randomreplacement.go
glightfoot 32c612d5e8 add license
Signed-off-by: glightfoot <glightfoot@rsglab.com>
2021-02-06 23:03:46 -05:00

83 lines
1.9 KiB
Go

// Copyright 2021 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 randomreplacement
import (
"sync"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/statsd_exporter/pkg/mapper_cache"
)
type metricMapperRRCache struct {
lock sync.RWMutex
size int
items map[string]interface{}
metrics *mapper_cache.CacheMetrics
}
func NewMetricMapperRRCache(reg prometheus.Registerer, size int) (*metricMapperRRCache, error) {
if size <= 0 {
return nil, nil
}
metrics := mapper_cache.NewCacheMetrics(reg)
c := &metricMapperRRCache{
items: make(map[string]interface{}, size+1),
size: size,
metrics: metrics,
}
return c, nil
}
func (m *metricMapperRRCache) Get(metricKey string) (interface{}, bool) {
m.lock.RLock()
result, ok := m.items[metricKey]
m.lock.RUnlock()
return result, ok
}
func (m *metricMapperRRCache) Add(metricKey string, result interface{}) {
go m.trackCacheLength()
m.lock.Lock()
m.items[metricKey] = 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) Reset() {
m.lock.Lock()
defer m.lock.Unlock()
m.items = make(map[string]interface{}, m.size+1)
m.metrics.CacheLength.Set(0)
}
func (m *metricMapperRRCache) trackCacheLength() {
m.lock.RLock()
length := len(m.items)
m.lock.RUnlock()
m.metrics.CacheLength.Set(float64(length))
}