mirror of
https://github.com/prometheus/prometheus.git
synced 2024-09-20 07:47:31 -07:00
144 lines
2.9 KiB
Go
144 lines
2.9 KiB
Go
// Copyright 2019 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// Inspired / copied / modified from https://gitlab.com/cznic/strutil/blob/master/strutil.go,
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// which is MIT licensed, so:
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//
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// Copyright (c) 2014 The strutil Authors. All rights reserved.
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package remote
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import (
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"sync"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promauto"
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"go.uber.org/atomic"
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)
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var noReferenceReleases = promauto.NewCounter(prometheus.CounterOpts{
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Namespace: namespace,
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Subsystem: subsystem,
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Name: "string_interner_zero_reference_releases_total",
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Help: "The number of times release has been called for strings that are not interned.",
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})
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type pool struct {
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mtx sync.RWMutex
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pool map[string]*entry
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}
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type entry struct {
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refs atomic.Int64
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s string
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}
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func newEntry(s string) *entry {
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return &entry{s: s}
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}
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func newPool() *pool {
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return &pool{
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pool: map[string]*entry{},
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}
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}
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func (p *pool) intern(s string) string {
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if s == "" {
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return ""
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}
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p.mtx.RLock()
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interned, ok := p.pool[s]
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p.mtx.RUnlock()
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if ok {
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interned.refs.Inc()
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return interned.s
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}
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p.mtx.Lock()
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defer p.mtx.Unlock()
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if interned, ok := p.pool[s]; ok {
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interned.refs.Inc()
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return interned.s
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}
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p.pool[s] = newEntry(s)
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p.pool[s].refs.Store(1)
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return s
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}
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func (p *pool) release(s string) {
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p.mtx.RLock()
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interned, ok := p.pool[s]
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p.mtx.RUnlock()
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if !ok {
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noReferenceReleases.Inc()
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return
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}
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refs := interned.refs.Dec()
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if refs > 0 {
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return
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}
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p.mtx.Lock()
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defer p.mtx.Unlock()
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if interned.refs.Load() != 0 {
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return
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}
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delete(p.pool, s)
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}
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// used to create a lookup table for a new remote write request, should not be used concurrently
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type lookupPool struct {
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nextRef uint64
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table map[uint64]string
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reverseTable map[string]uint64
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}
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func newLookupPool() *lookupPool {
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return &lookupPool{
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table: map[uint64]string{},
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reverseTable: map[string]uint64{},
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}
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}
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func (p *lookupPool) intern(s string) uint64 {
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if ref, ok := p.reverseTable[s]; ok {
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return ref
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}
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ref := p.nextRef
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p.reverseTable[s] = ref
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p.table[ref] = s
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p.nextRef++
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return ref
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}
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func (p *lookupPool) getTable() map[uint64]string {
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return p.table
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}
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func (p *lookupPool) clear() {
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for k := range p.table {
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delete(p.table, k)
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}
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for k := range p.reverseTable {
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delete(p.reverseTable, k)
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}
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p.nextRef = 0
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}
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