心跳处理基本流程
ClientBeatProcessor的run处理临时实例心跳
这里就体现出RsInfo的用途啦，其实就是保存下实例的相关信息，IP,端口，集群。遍历实例集群的实例，找出对应的IP和端口的实例进行状态更新。如果发现有问题，还要用PushService进行UDP进行通知，UDP端口是客户端请求的时候刷新服务实例列表的使用传上来的，客户端也有个PushReceiver就是来接受UDP报文信息，具体可以看这篇文章。
@Override
public void run() {
Service service = this.service;
...
String ip = rsInfo.getIp();//IP
String clusterName = rsInfo.getCluster();//集群名字
int port = rsInfo.getPort();//端口
Cluster cluster = service.getClusterMap().get(clusterName);//获取集群
List<Instance> instances = cluster.allIPs(true);//获取集群所有的临时服务实例
//遍历更新对应的状态
for (Instance instance : instances) {
if (instance.getIp().equals(ip) && instance.getPort() == port) {
if (Loggers.EVT_LOG.isDebugEnabled()) {
Loggers.EVT_LOG.debug("[CLIENT-BEAT] refresh beat: {}", rsInfo.toString());
}
instance.setLastBeat(System.currentTimeMillis());//刷新心跳时间
if (!instance.isMarked()) {//没被标记的
if (!instance.isHealthy()) {//不健康的
instance.setHealthy(true);//设置为健康
Loggers.EVT_LOG.info("service: {} {POS} {IP-ENABLED} valid: {}:{}@{}, region: {}, msg: client beat ok",
cluster.getService().getName(), ip, port, cluster.getName(), UtilsAndCommons.LOCALHOST_SITE);
getPushService().serviceChanged(service);//UDP发送服务改变通知
}
}
}
}
}
PushService的serviceChanged服务有改变UDP客户端
实现了监听接口：
缓存里没有的话，服务有改变的时候用上下文来发送ServiceChangeEvent事件。
UDP调度任务
其实就是遍历需要推送的客户端，然后封装数据，推送。
@Override
public void onApplicationEvent(ServiceChangeEvent event) {
Service service = event.getService();
String serviceName = service.getName();
String namespaceId = service.getNamespaceId();
Future future = udpSender.schedule(new Runnable() {
@Override
public void run() {
try {
...
//获取所有需要推送的PushClient
ConcurrentMap<String, PushClient> clients = clientMap.get(UtilsAndCommons.assembleFullServiceName(namespaceId, serviceName));
if (MapUtils.isEmpty(clients)) {
return;
}
Map<String, Object> cache = new HashMap<>(16);
long lastRefTime = System.nanoTime();
for (PushClient client : clients.values()) {
if (client.zombie()) {//超时的不删除不处理
...
clients.remove(client.toString());
...
continue;
}
Receiver.AckEntry ackEntry;
...
String key = getPushCacheKey(serviceName, client.getIp(), client.getAgent());
byte[] compressData = null;
Map<String, Object> data = null;
//有压缩数据
if (switchDomain.getDefaultPushCacheMillis() >= 20000 && cache.containsKey(key)) {
org.javatuples.Pair pair = (org.javatuples.Pair) cache.get(key);
compressData = (byte[]) (pair.getValue0());
data = (Map<String, Object>) pair.getValue1();
...
}
//准备UDP数据
if (compressData != null) {
ackEntry = prepareAckEntry(client, compressData, data, lastRefTime);
} else {
ackEntry = prepareAckEntry(client, prepareHostsData(client), lastRefTime);
if (ackEntry != null) {
cache.put(key, new org.javatuples.Pair<>(ackEntry.origin.getData(), ackEntry.data));
}
}
Loggers.PUSH.info("serviceName: {} changed, schedule push for: {}, agent: {}, key: {}",
client.getServiceName(), client.getAddrStr(), client.getAgent(), (ackEntry == null ? null : ackEntry.key));
//发送
udpPush(ackEntry);
}
} catch (Exception e) {
Loggers.PUSH.error("[NACOS-PUSH] failed to push serviceName: {} to client, error: {}", serviceName, e);
} finally {
//发送完删除
futureMap.remove(UtilsAndCommons.assembleFullServiceName(namespaceId, serviceName));
}
}
}, 1000, TimeUnit.MILLISECONDS);
//放缓存，不会重复发送
futureMap.put(UtilsAndCommons.assembleFullServiceName(namespaceId, serviceName), future);
}
udpPush
判断是否大于重试次数，因为UDP不可靠，可能发出去没收到，也可能客户端发来的没收到，所以要尝试，后面有开启任务重试的。然后封装好数据发送，再开启一个Retransmitter任务10秒后看有没有成功响应，没有的话就重新发送。
private static Receiver.AckEntry udpPush(Receiver.AckEntry ackEntry) {
if (ackEntry == null) {
Loggers.PUSH.error("[NACOS-PUSH] ackEntry is null.");
return null;
}
//大于尝试的次数
if (ackEntry.getRetryTimes() > MAX_RETRY_TIMES) {
Loggers.PUSH.warn("max re-push times reached, retry times {}, key: {}", ackEntry.retryTimes, ackEntry.key);
ackMap.remove(ackEntry.key);
udpSendTimeMap.remove(ackEntry.key);
failedPush += 1;
return ackEntry;
}
try {
if (!ackMap.containsKey(ackEntry.key)) {
totalPush++;
}
ackMap.put(ackEntry.key, ackEntry);
udpSendTimeMap.put(ackEntry.key, System.currentTimeMillis());
Loggers.PUSH.info("send udp packet: " + ackEntry.key);
udpSocket.send(ackEntry.origin);//发送UDP报文
ackEntry.increaseRetryTime();
//10秒没应答就再尝试一次
executorService.schedule(new Retransmitter(ackEntry), TimeUnit.NANOSECONDS.toMillis(ACK_TIMEOUT_NANOS),
TimeUnit.MILLISECONDS);
return ackEntry;
} catch (Exception e) {
Loggers.PUSH.error("[NACOS-PUSH] failed to push data: {} to client: {}, error: {}",
ackEntry.data, ackEntry.origin.getAddress().getHostAddress(), e);
ackMap.remove(ackEntry.key);
udpSendTimeMap.remove(ackEntry.key);
failedPush += 1;
return null;
}
}
Retransmitter
如果发现ackMap中还有，说明没收到客户端响应。
public static class Retransmitter implements Runnable {
Receiver.AckEntry ackEntry;
public Retransmitter(Receiver.AckEntry ackEntry) {
this.ackEntry = ackEntry;
}
@Override
public void run() {
if (ackMap.containsKey(ackEntry.key)) {//没接受到响应
Loggers.PUSH.info("retry to push data, key: " + ackEntry.key);
udpPush(ackEntry);
}
}
}
Receiver
如果收到客户端响应的话会从ackMap中删除ackEntry.key：
好了，心跳的接受，处理，如果有数据改变的通知和UDP推送原理基本都讲了，具体细节看源码吧。
好了，今天就到这里了，希望对学习理解有帮助，大神看见勿喷，仅为自己的学习理解，能力有限，请多包涵。
