Eureka 学习笔记1：服务端实例缓存

版本 awsVersion = ‘1.11.277’

缓存	类型
registry	ConcurrentHashMap<String, Map<String, Lease<InstanceInfo>>>	AbstractInstanceRegistry成员变量
readWriteCacheMap	LoadingCache	ResponseCacheImpl成员变量
readOnlyCacheMap	ConcurrentMap<Key, Value>	ResponseCacheImpl成员变量

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registry

// com.netflix.eureka.registry.AbstractInstanceRegistry
protected void postInit() {evictionTaskRef.set(new EvictionTask());evictionTimer.schedule(evictionTaskRef.get(),serverConfig.getEvictionIntervalTimerInMs(),// 配置evictionIntervalTimerInMsserverConfig.getEvictionIntervalTimerInMs());
}
class EvictionTask extends TimerTask {public void run() {long compensationTimeMs = getCompensationTimeMs();evict(compensationTimeMs);}// ...
}

evictionIntervalTimerInMs 指定清理未续约服务实例的时间间隔，默认 60s

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readWriteCacheMap

// com.netflix.eureka.registry.ResponseCacheImpl
this.readWriteCacheMap =CacheBuilder.newBuilder()// 配置initialCapacityOfResponseCache.initialCapacity(serverConfig.getInitialCapacityOfResponseCache())// 配置responseCacheAutoExpirationInSeconds.expireAfterWrite(serverConfig.getResponseCacheAutoExpirationInSeconds(), TimeUnit.SECONDS)

initialCapacityOfResponseCache 指定 readWriteCacheMap 缓存容量大小，默认 1000

responseCacheAutoExpirationInSeconds 指定 readWriteCacheMap 缓存有效时间，默认 180s

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readOnlyCacheMap

// com.netflix.eureka.registry.ResponseCacheImpl
// 配置shouldUseReadOnlyResponseCache
if (shouldUseReadOnlyResponseCache) {timer.schedule(getCacheUpdateTask(),new Date(((System.currentTimeMillis() / responseCacheUpdateIntervalMs) * responseCacheUpdateIntervalMs)+ responseCacheUpdateIntervalMs),// 配置responseCacheUpdateIntervalMsresponseCacheUpdateIntervalMs);
}private TimerTask getCacheUpdateTask() {return new TimerTask() {public void run() {// ...    for (Key key : readOnlyCacheMap.keySet()) {CurrentRequestVersion.set(key.getVersion());Value cacheValue = readWriteCacheMap.get(key);Value currentCacheValue = readOnlyCacheMap.get(key);if (cacheValue != currentCacheValue) {readOnlyCacheMap.put(key, cacheValue);}}}};
}

shouldUseReadOnlyResponseCache 指定是否使用 readOnlyCacheMap，默认 true

responseCacheUpdateIntervalMs 指定 readOnlyCacheMap 更新的时间间隔，默认 30s