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本文主要研究一下nacos的ServerChangeListener
ServerChangeListener
nacos-1.1.3/naming/src/main/java/com/alibaba/nacos/naming/cluster/servers/ServerChangeListener.java
public interface ServerChangeListener {
/**
* If member list changed, this method is invoked.
*
* @param servers servers after change
*/
void onChangeServerList(List servers);
/**
* If reachable member list changed, this method is invoked.
*
* @param healthyServer reachable servers after change
*/
void onChangeHealthyServerList(List healthyServer);
}
ServerChangeListener定义了onChangeServerList、onChangeHealthyServerList方法
DistroMapper
nacos-1.1.3/naming/src/main/java/com/alibaba/nacos/naming/core/DistroMapper.java
@Component("distroMapper")
public class DistroMapper implements ServerChangeListener {
private List healthyList = new ArrayList<>();
//......
@Override
public void onChangeServerList(List latestMembers) {
}
@Override
public void onChangeHealthyServerList(List latestReachableMembers) {
List newHealthyList = new ArrayList<>();
for (Server server : latestReachableMembers) {
newHealthyList.add(server.getKey());
}
healthyList = newHealthyList;
}
//......
}
DistroMapper实现了ServerChangeListener接口，其onChangeHealthyServerList会更新自己的healthyList
RaftPeerSet
nacos-1.1.3/naming/src/main/java/com/alibaba/nacos/naming/consistency/persistent/raft/RaftPeerSet.java
@Component
@DependsOn("serverListManager")
public class RaftPeerSet implements ServerChangeListener, ApplicationContextAware {
@Autowired
private ServerListManager serverListManager;
private ApplicationContext applicationContext;
private AtomicLong localTerm = new AtomicLong(0L);
private RaftPeer leader = null;
private Map peers = new HashMap<>();
private Set sites = new HashSet<>();
private boolean ready = false;
//......
@Override
public void onChangeServerList(List latestMembers) {
Map tmpPeers = new HashMap<>(8);
for (Server member : latestMembers) {
if (peers.containsKey(member.getKey())) {
tmpPeers.put(member.getKey(), peers.get(member.getKey()));
continue;
}
RaftPeer raftPeer = new RaftPeer();
raftPeer.ip = member.getKey();
// first time meet the local server:
if (NetUtils.localServer().equals(member.getKey())) {
raftPeer.term.set(localTerm.get());
}
tmpPeers.put(member.getKey(), raftPeer);
}
// replace raft peer set:
peers = tmpPeers;
if (RunningConfig.getServerPort() > 0) {
ready = true;
}
Loggers.RAFT.info("raft peers changed: " + latestMembers);
}
@Override
public void onChangeHealthyServerList(List latestReachableMembers) {
}
//......
}
RaftPeerSet实现了ServerChangeListener接口，其onChangeServerList方法会更新peers及ready属性
小结
ServerChangeListener定义了onChangeServerList、onChangeHealthyServerList方法；DistroMapper实现了ServerChangeListener接口，其onChangeHealthyServerList会更新自己的healthyList；RaftPeerSet实现了ServerChangeListener接口，其onChangeServerList方法会更新peers及ready属性
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