AlexStocks commented on code in PR #3612: URL: https://github.com/apache/dubbo-go/pull/3612#discussion_r3740276207
########## config_center/zookeeper/config_cache.go: ########## @@ -0,0 +1,237 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 zookeeper + +import ( + "sync" + "time" +) + +type configCacheEntry struct { + content string + exists bool + expiresAt time.Time +} + +type configCache struct { + ttl time.Duration + + stateLock sync.RWMutex + entries map[string]configCacheEntry + watches map[string]bool + generation uint64 + + pathLocks sync.Map +} + +func newConfigCache(ttl time.Duration) configCache { + return configCache{ + ttl: ttl, + entries: make(map[string]configCacheEntry), + watches: make(map[string]bool), + } +} + +func (c *configCache) enabled() bool { + return c.ttl > 0 +} + +func (c *configCache) load(path string, loader func(bool) (configCacheEntry, bool, error)) (configCacheEntry, error) { + if !c.enabled() { + entry, _, err := loader(false) + return entry, err + } + if entry, ok := c.getFresh(path); ok { + return entry, nil + } + + pathLock := c.pathLock(path) + pathLock.Lock() + defer pathLock.Unlock() + + for { + if entry, ok := c.getFresh(path); ok { + return entry, nil + } + + generation, watchActive := c.snapshot(path) + entry, nextWatchActive, err := loader(watchActive) + if err != nil { + if !c.storeWatchState(path, generation, nextWatchActive) { + continue + } + return configCacheEntry{}, err + } + if !c.storeLoad(path, generation, entry, nextWatchActive) { + continue + } + return entry, nil + } +} + +func (c *configCache) store(path string, entry configCacheEntry) { + if !c.enabled() { + return + } + pathLock := c.pathLock(path) + pathLock.Lock() + defer pathLock.Unlock() + + c.stateLock.Lock() + defer c.stateLock.Unlock() + c.storeEntryLocked(path, entry) +} + +func (c *configCache) storeAtGeneration(path string, generation uint64, entry configCacheEntry) { + if !c.enabled() { + return + } + pathLock := c.pathLock(path) + pathLock.Lock() + defer pathLock.Unlock() + + c.stateLock.Lock() + defer c.stateLock.Unlock() + if c.generation == generation { + c.storeEntryLocked(path, entry) + } +} + +func (c *configCache) getFresh(path string) (configCacheEntry, bool) { + c.stateLock.RLock() + defer c.stateLock.RUnlock() + + entry, ok := c.entries[path] + if !ok { + return configCacheEntry{}, false + } + return entry, entry.expiresAt.After(time.Now()) +} + +func (c *configCache) storeEntryLocked(path string, entry configCacheEntry) { + entry.expiresAt = time.Now().Add(c.ttl) + c.entries[path] = entry +} + +func (c *configCache) snapshot(path string) (uint64, bool) { + c.stateLock.RLock() + defer c.stateLock.RUnlock() + return c.generation, c.watches[path] +} + +func (c *configCache) isCurrentGeneration(generation uint64) bool { + c.stateLock.RLock() + defer c.stateLock.RUnlock() + return c.generation == generation +} + +func (c *configCache) storeLoad(path string, generation uint64, entry configCacheEntry, watchActive bool) bool { + c.stateLock.Lock() + defer c.stateLock.Unlock() + if c.generation != generation { + return false + } + + c.storeEntryLocked(path, entry) + c.setWatchActiveLocked(path, watchActive) + return true +} + +func (c *configCache) storeWatchState(path string, generation uint64, watchActive bool) bool { + c.stateLock.Lock() + defer c.stateLock.Unlock() + if c.generation != generation { + return false + } + c.setWatchActiveLocked(path, watchActive) + return true +} + +func (c *configCache) setWatchActive(path string, active bool) { + if !c.enabled() { + return + } + pathLock := c.pathLock(path) + pathLock.Lock() + defer pathLock.Unlock() + + c.stateLock.Lock() + defer c.stateLock.Unlock() + c.setWatchActiveLocked(path, active) +} + +func (c *configCache) setWatchActiveAtGeneration(path string, generation uint64, active bool) { + if !c.enabled() { + return + } + pathLock := c.pathLock(path) + pathLock.Lock() + defer pathLock.Unlock() + c.storeWatchState(path, generation, active) +} + +func (c *configCache) setWatchActiveLocked(path string, active bool) { + if active { + c.watches[path] = true + return + } + delete(c.watches, path) +} + +func (c *configCache) ensureWatch(path string, register func() error) error { + if !c.enabled() { + return register() + } + pathLock := c.pathLock(path) + pathLock.Lock() + defer pathLock.Unlock() + + for { + generation, active := c.snapshot(path) + if active { + return nil + } + if err := register(); err != nil { + if !c.isCurrentGeneration(generation) { + continue + } + return err + } + + c.stateLock.Lock() + if c.generation == generation { + c.watches[path] = true + c.stateLock.Unlock() + return nil + } + c.stateLock.Unlock() + } +} + +func (c *configCache) reset() { + c.stateLock.Lock() + defer c.stateLock.Unlock() + c.generation++ + c.entries = make(map[string]configCacheEntry) + c.watches = make(map[string]bool) +} + +func (c *configCache) pathLock(path string) *sync.Mutex { + lock, _ := c.pathLocks.LoadOrStore(path, &sync.Mutex{}) Review Comment: [P1] 为缓存增加有界淘汰并回收每路径状态 `GetProperties` 接受任意 key/group；每个新路径都会在这里永久写入一个 `pathLocks` 条目，同时 `entries`（包括 missing node）和 `watches` 也只过期、不删除。`expiresAt` 仅触发重新加载，`reset()` 也没有清理 `pathLocks`。隔离探针访问 4096 个唯一路径后，TTL 过期仍保留 4096 个 entries/watches，reset 后仍保留 4096 个 path lock。动态 dataId、租户或错误 key 持续变化时，进程内存会按历史 key 数线性增长。请增加最大容量和 TTL/LRU 淘汰，并在安全处理 in-flight load 的前提下同步回收 entry、watch 状态和 path lock；补充唯一 key churn、missing key、过期、reset 与并发 load 的容量回归测试。 -- This is an automated message from the Apache Git Service. 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