共计 9387 个字符，预计需要花费 24 分钟才能阅读完成。
序
本文主要研究一下 NacosNamingService 的 selectInstances
NacosNamingService
nacos-1.1.3/client/src/main/java/com/alibaba/nacos/client/naming/NacosNamingService.java
public class NacosNamingService implements NamingService {
private static final String DEFAULT_PORT = "8080";
private static final long DEFAULT_HEART_BEAT_INTERVAL = TimeUnit.SECONDS.toMillis(5);
/**
* Each Naming instance should have different namespace.
*/
private String namespace;
private String endpoint;
private String serverList;
private String cacheDir;
private String logName;
private HostReactor hostReactor;
private BeatReactor beatReactor;
private EventDispatcher eventDispatcher;
private NamingProxy serverProxy;
//......
@Override
public List<Instance> selectInstances(String serviceName, boolean healthy) throws NacosException {return selectInstances(serviceName, new ArrayList<String>(), healthy);
}
@Override
public List<Instance> selectInstances(String serviceName, String groupName, boolean healthy) throws NacosException {return selectInstances(serviceName, groupName, healthy, true);
}
@Override
public List<Instance> selectInstances(String serviceName, boolean healthy, boolean subscribe)
throws NacosException {return selectInstances(serviceName, new ArrayList<String>(), healthy, subscribe);
}
@Override
public List<Instance> selectInstances(String serviceName, String groupName, boolean healthy, boolean subscribe) throws NacosException {return selectInstances(serviceName, groupName, new ArrayList<String>(), healthy, subscribe);
}
@Override
public List<Instance> selectInstances(String serviceName, List<String> clusters, boolean healthy)
throws NacosException {return selectInstances(serviceName, clusters, healthy, true);
}
@Override
public List<Instance> selectInstances(String serviceName, String groupName, List<String> clusters, boolean healthy) throws NacosException {return selectInstances(serviceName, groupName, clusters, healthy, true);
}
@Override
public List<Instance> selectInstances(String serviceName, List<String> clusters, boolean healthy,
boolean subscribe) throws NacosException {return selectInstances(serviceName, Constants.DEFAULT_GROUP, clusters, healthy, subscribe);
}
@Override
public List<Instance> selectInstances(String serviceName, String groupName, List<String> clusters, boolean healthy, boolean subscribe) throws NacosException {
ServiceInfo serviceInfo;
if (subscribe) {serviceInfo = hostReactor.getServiceInfo(NamingUtils.getGroupedName(serviceName, groupName), StringUtils.join(clusters, ","));
} else {serviceInfo = hostReactor.getServiceInfoDirectlyFromServer(NamingUtils.getGroupedName(serviceName, groupName), StringUtils.join(clusters, ","));
}
return selectInstances(serviceInfo, healthy);
}
private List<Instance> selectInstances(ServiceInfo serviceInfo, boolean healthy) {
List<Instance> list;
if (serviceInfo == null || CollectionUtils.isEmpty(list = serviceInfo.getHosts())) {return new ArrayList<Instance>();
}
Iterator<Instance> iterator = list.iterator();
while (iterator.hasNext()) {Instance instance = iterator.next();
if (healthy != instance.isHealthy() || !instance.isEnabled() || instance.getWeight() <= 0) {iterator.remove();
}
}
return list;
}
//......
}- selectInstances 首先从 hostReactor 获取 serviceInfo，然后再从 serviceInfo.getHosts()剔除非 healty、非 enabled、weight 小于等于 0 的 instance 再返回；如果 subscribe 为 true，则执行 hostReactor.getServiceInfo 获取 serviceInfo，否则执行 hostReactor.getServiceInfoDirectlyFromServer 获取 serviceInfo
HostReactor
nacos-1.1.3/client/src/main/java/com/alibaba/nacos/client/naming/core/HostReactor.java
public class HostReactor {
private static final long DEFAULT_DELAY = 1000L;
private static final long UPDATE_HOLD_INTERVAL = 5000L;
private final Map<String, ScheduledFuture<?>> futureMap = new HashMap<String, ScheduledFuture<?>>();
private Map<String, ServiceInfo> serviceInfoMap;
private Map<String, Object> updatingMap;
private PushReceiver pushReceiver;
private EventDispatcher eventDispatcher;
private NamingProxy serverProxy;
private FailoverReactor failoverReactor;
private String cacheDir;
private ScheduledExecutorService executor;
//......
public ServiceInfo getServiceInfo(final String serviceName, final String clusters) {NAMING_LOGGER.debug("failover-mode:" + failoverReactor.isFailoverSwitch());
String key = ServiceInfo.getKey(serviceName, clusters);
if (failoverReactor.isFailoverSwitch()) {return failoverReactor.getService(key);
}
ServiceInfo serviceObj = getServiceInfo0(serviceName, clusters);
if (null == serviceObj) {serviceObj = new ServiceInfo(serviceName, clusters);
serviceInfoMap.put(serviceObj.getKey(), serviceObj);
updatingMap.put(serviceName, new Object());
updateServiceNow(serviceName, clusters);
updatingMap.remove(serviceName);
} else if (updatingMap.containsKey(serviceName)) {if (UPDATE_HOLD_INTERVAL > 0) {
// hold a moment waiting for update finish
synchronized (serviceObj) {
try {serviceObj.wait(UPDATE_HOLD_INTERVAL);
} catch (InterruptedException e) {NAMING_LOGGER.error("[getServiceInfo] serviceName:" + serviceName + ", clusters:" + clusters, e);
}
}
}
}
scheduleUpdateIfAbsent(serviceName, clusters);
return serviceInfoMap.get(serviceObj.getKey());
}
private ServiceInfo getServiceInfo0(String serviceName, String clusters) {String key = ServiceInfo.getKey(serviceName, clusters);
return serviceInfoMap.get(key);
}
public void updateServiceNow(String serviceName, String clusters) {ServiceInfo oldService = getServiceInfo0(serviceName, clusters);
try {String result = serverProxy.queryList(serviceName, clusters, pushReceiver.getUDPPort(), false);
if (StringUtils.isNotEmpty(result)) {processServiceJSON(result);
}
} catch (Exception e) {NAMING_LOGGER.error("[NA] failed to update serviceName:" + serviceName, e);
} finally {if (oldService != null) {synchronized (oldService) {oldService.notifyAll();
}
}
}
}
public void scheduleUpdateIfAbsent(String serviceName, String clusters) {if (futureMap.get(ServiceInfo.getKey(serviceName, clusters)) != null) {return;}
synchronized (futureMap) {if (futureMap.get(ServiceInfo.getKey(serviceName, clusters)) != null) {return;}
ScheduledFuture<?> future = addTask(new UpdateTask(serviceName, clusters));
futureMap.put(ServiceInfo.getKey(serviceName, clusters), future);
}
}
public ServiceInfo getServiceInfoDirectlyFromServer(final String serviceName, final String clusters) throws NacosException {String result = serverProxy.queryList(serviceName, clusters, 0, false);
if (StringUtils.isNotEmpty(result)) {return JSON.parseObject(result, ServiceInfo.class);
}
return null;
}
//......
}- getServiceInfo 首先判断 failoverReactor.isFailoverSwitch()，如果是则返回 failoverReactor.getService(key)；接着通过 getServiceInfo0 从 serviceInfoMap 查找，如果找不到则创建一个新的然后放入 serviceInfoMap，同时放入 updatingMap，执行 updateServiceNow，再从 updatingMap 移除；如果从 serviceInfoMap 找出来的 serviceObj 在 updatingMap 中则等待 UPDATE_HOLD_INTERVAL；最后执行 scheduleUpdateIfAbsent，再从 serviceInfoMap 取出 serviceInfo
- updateServiceNow 则从 serverProxy.queryList 获取结果，然后通过 processServiceJSON 解析并根据需要更新 serviceInfoMap；scheduleUpdateIfAbsent 方法判断 futureMap 是否有该任务，如果没有则添加一个 UpdateTask
- getServiceInfoDirectlyFromServer 方法则直接请求 serverProxy.queryList 获取 ServiceInfo
UpdateTask
nacos-1.1.3/client/src/main/java/com/alibaba/nacos/client/naming/core/HostReactor.java
public class UpdateTask implements Runnable {
long lastRefTime = Long.MAX_VALUE;
private String clusters;
private String serviceName;
public UpdateTask(String serviceName, String clusters) {
this.serviceName = serviceName;
this.clusters = clusters;
}
@Override
public void run() {
try {ServiceInfo serviceObj = serviceInfoMap.get(ServiceInfo.getKey(serviceName, clusters));
if (serviceObj == null) {updateServiceNow(serviceName, clusters);
executor.schedule(this, DEFAULT_DELAY, TimeUnit.MILLISECONDS);
return;
}
if (serviceObj.getLastRefTime() <= lastRefTime) {updateServiceNow(serviceName, clusters);
serviceObj = serviceInfoMap.get(ServiceInfo.getKey(serviceName, clusters));
} else {
// if serviceName already updated by push, we should not override it
// since the push data may be different from pull through force push
refreshOnly(serviceName, clusters);
}
executor.schedule(this, serviceObj.getCacheMillis(), TimeUnit.MILLISECONDS);
lastRefTime = serviceObj.getLastRefTime();} catch (Throwable e) {NAMING_LOGGER.warn("[NA] failed to update serviceName:" + serviceName, e);
}
}
}
public void refreshOnly(String serviceName, String clusters) {
try {serverProxy.queryList(serviceName, clusters, pushReceiver.getUDPPort(), false);
} catch (Exception e) {NAMING_LOGGER.error("[NA] failed to update serviceName:" + serviceName, e);
}
}
- UpdateTask 实现了 Runnable 接口，其 run 方法首先从 serviceInfoMap 获取 serviceObj，获取不到则执行 updateServiceNow，然后再次延时调度 UpdateTask；可以从 serviceInfoMap 获取 serviceObj 的话则判断 serviceObj.getLastRefTime()是否小于等于 lastRefTime，是的话则执行 updateServiceNow，否则执行 refreshOnly；最后再次延时调度 UpdateTask，并更新 lastRefTime
NamingProxy
nacos-1.1.3/client/src/main/java/com/alibaba/nacos/client/naming/net/NamingProxy.java
public class NamingProxy {
private static final int DEFAULT_SERVER_PORT = 8848;
private int serverPort = DEFAULT_SERVER_PORT;
private String namespaceId;
private String endpoint;
private String nacosDomain;
private List<String> serverList;
private List<String> serversFromEndpoint = new ArrayList<String>();
private long lastSrvRefTime = 0L;
private long vipSrvRefInterMillis = TimeUnit.SECONDS.toMillis(30);
private Properties properties;
//......
public String queryList(String serviceName, String clusters, int udpPort, boolean healthyOnly)
throws NacosException {final Map<String, String> params = new HashMap<String, String>(8);
params.put(CommonParams.NAMESPACE_ID, namespaceId);
params.put(CommonParams.SERVICE_NAME, serviceName);
params.put("clusters", clusters);
params.put("udpPort", String.valueOf(udpPort));
params.put("clientIP", NetUtils.localIP());
params.put("healthyOnly", String.valueOf(healthyOnly));
return reqAPI(UtilAndComs.NACOS_URL_BASE + "/instance/list", params, HttpMethod.GET);
}
//......
}- queryList 方法会往
/instance/list接口发送 GET 请求查询服务实例列表
小结
selectInstances 首先从 hostReactor 获取 serviceInfo，然后再从 serviceInfo.getHosts()剔除非 healty、非 enabled、weight 小于等于 0 的 instance 再返回；如果 subscribe 为 true，则执行 hostReactor.getServiceInfo 获取 serviceInfo，否则执行 hostReactor.getServiceInfoDirectlyFromServer 获取 serviceInfo
doc
- NacosNamingService
正文完
