springboot eureka 註冊服務探索
阿新 • • 發佈：2019-01-22
執行時日誌
2018-03-09 13:16:42.132 INFO 13652 --- [a-EvictionTimer] c.n.e.registry.AbstractInstanceRegistry : Running the evict task with compensationTime 0ms
2018-03-09 13:17:42.141 INFO 13652 --- [a-EvictionTimer] c.n.e.registry.AbstractInstanceRegistry : Running the evict task with compensationTime 7ms
2018 #跟程式碼
com.netflix.eureka.registry.AbstractInstanceRegistry.register(InstanceInfo registrant, int leaseDuration, boolean isReplication)//註冊資訊，註冊資訊持續時間 預設120，是否複製
1.加同步鎖讀取鎖
2.在該類的常量registry（ConcurrentHashMap<String, Map<String, Lease<InstanceInfo>>>）根據取服務名（spring: application: name: eureka ）獲取所有註冊機（ rtn:Map<String, Lease<InstanceInfo>> gMap）
3.=====（監聽）EurekaMonitors.REGISTER.increment(isReplication); 監聽註冊服務的個數，增加服務計數（EurekaMonitors的myZoneCounter屬性），isReplication為falses時才進行計數增長。//主要是對 AtomicLong[extends Number implements java.io.Serializable]內的unsafe常量
4.判斷2是否獲取到有效eureka服務，若沒有則
if (gMap == null) {
ConcurrentHashMap<String, Lease<InstanceInfo>> gNewMap = new ConcurrentHashMap();
gMap = (Map)this.registry.putIfAbsent(registrant.getAppName(), gNewMap);
if (gMap == null) {
gMap = gNewMap;
}
}
5.獲取existingLease(生存週期)資訊，從2返回的map內，根據註冊資訊(instanceId[16101164-15-PC:eureka:8001]或eureka.instance.hostName[eureka1])，Lease<InstanceInfo> existingLease = (Lease)((Map)gMap).get(registrant.getId());
if (existingLease != null && existingLease.getHolder() != null) {
Long existingLastDirtyTimestamp = ((InstanceInfo)existingLease.getHolder()).getLastDirtyTimestamp();
Long registrationLastDirtyTimestamp = registrant.getLastDirtyTimestamp();
logger.debug("Existing lease found (existing={}, provided={}", existingLastDirtyTimestamp, registrationLastDirtyTimestamp);
if (existingLastDirtyTimestamp > registrationLastDirtyTimestamp) {
logger.warn("There is an existing lease and the existing lease's dirty timestamp {} is greater than the one that is being registered {}", existingLastDirtyTimestamp, registrationLastDirtyTimestamp);
logger.warn("Using the existing instanceInfo instead of the new instanceInfo as the registrant");
registrant = (InstanceInfo)existingLease.getHolder();
}
} else {
Object var6 = this.lock;
synchronized(this.lock) {
if (this.expectedNumberOfRenewsPerMin > 0) {
this.expectedNumberOfRenewsPerMin += 2;
this.numberOfRenewsPerMinThreshold = (int)((double)this.expectedNumberOfRenewsPerMin * this.serverConfig.getRenewalPercentThreshold());
}
}
logger.debug("No previous lease information found; it is new registration");
}
Lease<InstanceInfo> lease = new Lease(registrant, leaseDuration);
if (existingLease != null) {
lease.setServiceUpTimestamp(existingLease.getServiceUpTimestamp());
}
6.獲取最近註冊佇列recentRegisteredQueue【AbstractInstanceRegistry.CircularQueue<Pair<Long, String>>】，
對佇列加鎖，將待註冊的服務資訊註冊（當前系統時間戳 ，當前待註冊服務名eg:ees-hotel + id(instanceId/hostName)），
synchronized(this.recentRegisteredQueue) {
this.recentRegisteredQueue.add(new Pair(System.currentTimeMillis(), registrant.getAppName() + "(" + registrant.getId() + ")"));
}
7.註冊資訊的overriddenStatus狀態不是InstanceStatus.UNKNOWN時，將當前服務註冊資訊內的此狀態維護到overriddenInstanceStatusMap，key為id.
8.將overriddenInstanceStatusMap內的OverriddenStatus同步到註冊資訊registrant內，當overriddenStatusFromMap記憶體在此狀態時。
9.當註冊資訊registrant的狀態為InstanceStatus.UP時，更新lease的存活【租約】時間，服務開始時間為當前時間戳。
10.註冊資訊的actionType設定為在發現服務中新增，將當前註冊的服務新增到服務發現內。
11.將新註冊（更改）的服務資訊（lease）新增到最近更改佇列（recentlyChangedQueue）
12.設定新註冊的服務的最後更新時間
13.this.invalidateCache(registrant.getAppName(), registrant.getVIPAddress(), registrant.getSecureVipAddress()); 使快取無效
快取使用的是Google的private final LoadingCache<Key, ResponseCacheImpl.Value> readWriteCacheMap; 該介面繼承Cache,存在invalidate抽象方法，實際呼叫LocalCache.LocalManualCache.invalidate,如下
public void invalidate(Object key) {
Preconditions.checkNotNull(key);
this.localCache.remove(key);
}
其中使用Preconditions的checkNotNull做非空校驗
最後在final LocalCache<K, V> localCache;內刪除快取的資訊。
LoadingCache extends Cache,Function
LocalCache implements Cache
LocalManualCache implements Cache
Manual內操作
此處刪除快取是迴圈操作，在初次啟動時會刪除
this.invalidate(new Key(EntityType.Application, appName, type, v, EurekaAccept.full), new Key(EntityType.Application, appName, type, v, EurekaAccept.compact), new Key(EntityType.Application, "ALL_APPS", type, v, EurekaAccept.full), new Key(EntityType.Application, "ALL_APPS", type, v, EurekaAccept.compact), new Key(EntityType.Application, "ALL_APPS_DELTA", type, v, EurekaAccept.full), new Key(EntityType.Application, "ALL_APPS_DELTA", type, v, EurekaAccept.compact));
ResponseCacheImpl構造方法會初始化readWriteCacheMap，initialCapacity=1000
this.readWriteCacheMap = CacheBuilder.newBuilder().initialCapacity(1000).expireAfterWrite(serverConfig.getResponseCacheAutoExpirationInSeconds(), TimeUnit.SECONDS).removalListener(new RemovalListener<Key, ResponseCacheImpl.Value>() {
public void onRemoval(RemovalNotification<Key, ResponseCacheImpl.Value> notification) {
Key removedKey = (Key)notification.getKey();
if (removedKey.hasRegions()) {
Key cloneWithNoRegions = removedKey.cloneWithoutRegions();
ResponseCacheImpl.this.regionSpecificKeys.remove(cloneWithNoRegions, removedKey);
}
}
}).build(new CacheLoader<Key, ResponseCacheImpl.Value>() {
public ResponseCacheImpl.Value load(Key key) throws Exception {
if (key.hasRegions()) {
Key cloneWithNoRegions = key.cloneWithoutRegions();
ResponseCacheImpl.this.regionSpecificKeys.put(cloneWithNoRegions, key);
}
ResponseCacheImpl.Value value = ResponseCacheImpl.this.generatePayload(key);
return value;
}
});未完待續