#497 Make subscription by query optional

api/src/main/java/com/alibaba/nacos/api/naming/NamingService.java

@@ -89,6 +89,16 @@ public interface NamingService {
      */
     List<Instance> getAllInstances(String serviceName) throws NacosException;
 
+    /**
+     * Get all instances of a service
+     *
+     * @param serviceName name of service
+     * @param subscribe   if subscribe the service
+     * @return A list of instance
+     * @throws NacosException
+     */
+    List<Instance> getAllInstances(String serviceName, boolean subscribe) throws NacosException;
+
     /**
      * Get all instances within specified clusters of a service
      *
@@ -99,6 +109,17 @@ public interface NamingService {
      */
     List<Instance> getAllInstances(String serviceName, List<String> clusters) throws NacosException;
 
+    /**
+     * Get all instances within specified clusters of a service
+     *
+     * @param serviceName name of service
+     * @param clusters    list of cluster
+     * @param subscribe   if subscribe the service
+     * @return A list of qualified instance
+     * @throws NacosException
+     */
+    List<Instance> getAllInstances(String serviceName, List<String> clusters, boolean subscribe) throws NacosException;
+
     /**
      * Get qualified instances of service
      *
@@ -109,6 +130,17 @@ public interface NamingService {
      */
     List<Instance> selectInstances(String serviceName, boolean healthy) throws NacosException;
 
+    /**
+     * Get qualified instances of service
+     *
+     * @param serviceName name of service
+     * @param healthy     a flag to indicate returning healthy or unhealthy instances
+     * @param subscribe   if subscribe the service
+     * @return A qualified list of instance
+     * @throws NacosException
+     */
+    List<Instance> selectInstances(String serviceName, boolean healthy, boolean subscribe) throws NacosException;
+
     /**
      * Get qualified instances within specified clusters of service
      *
@@ -120,6 +152,18 @@ public interface NamingService {
      */
     List<Instance> selectInstances(String serviceName, List<String> clusters, boolean healthy) throws NacosException;
 
+    /**
+     * Get qualified instances within specified clusters of service
+     *
+     * @param serviceName name of service
+     * @param clusters    list of cluster
+     * @param healthy     a flag to indicate returning healthy or unhealthy instances
+     * @param subscribe   if subscribe the service
+     * @return A qualified list of instance
+     * @throws NacosException
+     */
+    List<Instance> selectInstances(String serviceName, List<String> clusters, boolean healthy, boolean subscribe) throws NacosException;
+
     /**
      * Select one healthy instance of service using predefined load balance strategy
      *
@@ -129,6 +173,16 @@ public interface NamingService {
      */
     Instance selectOneHealthyInstance(String serviceName) throws NacosException;
 
+    /**
+     * Select one healthy instance of service using predefined load balance strategy
+     *
+     * @param serviceName name of service
+     * @param subscribe   if subscribe the service
+     * @return qualified instance
+     * @throws NacosException
+     */
+    Instance selectOneHealthyInstance(String serviceName, boolean subscribe) throws NacosException;
+
     /**
      * Select one healthy instance of service using predefined load balance strategy
      *
@@ -139,6 +193,17 @@ public interface NamingService {
      */
     Instance selectOneHealthyInstance(String serviceName, List<String> clusters) throws NacosException;
 
+    /**
+     * Select one healthy instance of service using predefined load balance strategy
+     *
+     * @param serviceName name of service
+     * @param clusters    a list of clusters should the instance belongs to
+     * @param subscribe   if subscribe the service
+     * @return qualified instance
+     * @throws NacosException
+     */
+    Instance selectOneHealthyInstance(String serviceName, List<String> clusters, boolean subscribe) throws NacosException;
+
     /**
      * Subscribe service to receive events of instances alteration
      *

client/src/main/java/com/alibaba/nacos/client/naming/NacosNamingService.java

@@ -20,7 +20,6 @@ import com.alibaba.nacos.api.common.Constants;
 import com.alibaba.nacos.api.exception.NacosException;
 import com.alibaba.nacos.api.naming.NamingService;
 import com.alibaba.nacos.api.naming.listener.EventListener;
-import com.alibaba.nacos.api.naming.pojo.Cluster;
 import com.alibaba.nacos.api.naming.pojo.Instance;
 import com.alibaba.nacos.api.naming.pojo.ListView;
 import com.alibaba.nacos.api.naming.pojo.ServiceInfo;
@@ -189,10 +188,25 @@ public class NacosNamingService implements NamingService {
     }
 
     @Override
-    public List<Instance> getAllInstances(String serviceName, List<String> clusters) throws NacosException {
+    public List<Instance> getAllInstances(String serviceName, boolean subscribe) throws NacosException {
+        return getAllInstances(serviceName, new ArrayList<String>(), subscribe);
+    }
 
-        ServiceInfo serviceInfo = hostReactor.getServiceInfo(serviceName, StringUtils.join(clusters, ","),
+    @Override
+    public List<Instance> getAllInstances(String serviceName, List<String> clusters) throws NacosException {
+        return getAllInstances(serviceName, clusters, true);
+    }
+
+    @Override
+    public List<Instance> getAllInstances(String serviceName, List<String> clusters, boolean subscribe) throws NacosException {
+
+        ServiceInfo serviceInfo;
+        if (subscribe) {
+            serviceInfo = hostReactor.getServiceInfo(serviceName, StringUtils.join(clusters, ","),
                 StringUtils.EMPTY, false);
+        } else {
+            serviceInfo = hostReactor.getServiceInfoDirectlyFromServer(serviceName, StringUtils.join(clusters, ","));
+        }
         List<Instance> list;
         if (serviceInfo == null || CollectionUtils.isEmpty(list = serviceInfo.getHosts())) {
             return new ArrayList<Instance>();
@@ -201,41 +215,60 @@ public class NacosNamingService implements NamingService {
     }
 
     @Override
-    public List<Instance> selectInstances(String serviceName, boolean healthyOnly) throws NacosException {
+    public List<Instance> selectInstances(String serviceName, boolean healthy) throws NacosException {
-        return selectInstances(serviceName, new ArrayList<String>(), healthyOnly);
+        return selectInstances(serviceName, new ArrayList<String>(), healthy);
+    }
+
+    @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, List<String> clusters, boolean healthy)
         throws NacosException {
-
+        return selectInstances(serviceName, clusters, healthy, true);
-        ServiceInfo serviceInfo = hostReactor.getServiceInfo(serviceName, StringUtils.join(clusters, ","),
-            StringUtils.EMPTY, false);
-        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;
     }
 
     @Override
-    public Instance selectOneHealthyInstance(String serviceName) {
+    public List<Instance> selectInstances(String serviceName, List<String> clusters, boolean healthy,
+                                          boolean subscribe) throws NacosException {
+
+        ServiceInfo serviceInfo;
+        if (subscribe) {
+            serviceInfo = hostReactor.getServiceInfo(serviceName, StringUtils.join(clusters, ","),
+                StringUtils.EMPTY, false);
+        } else {
+            serviceInfo = hostReactor.getServiceInfoDirectlyFromServer(serviceName, StringUtils.join(clusters, ","));
+        }
+        return selectInstances(serviceInfo, healthy);
+    }
+
+    @Override
+    public Instance selectOneHealthyInstance(String serviceName) throws NacosException {
         return selectOneHealthyInstance(serviceName, new ArrayList<String>());
     }
 
     @Override
-    public Instance selectOneHealthyInstance(String serviceName, List<String> clusters) {
+    public Instance selectOneHealthyInstance(String serviceName, boolean subscribe) throws NacosException {
+        return selectOneHealthyInstance(serviceName, new ArrayList<String>(), subscribe);
+    }
+
+    @Override
+    public Instance selectOneHealthyInstance(String serviceName, List<String> clusters) throws NacosException {
+        return selectOneHealthyInstance(serviceName, clusters, true);
+    }
+
+    @Override
+    public Instance selectOneHealthyInstance(String serviceName, List<String> clusters, boolean subscribe) throws NacosException {
+
+        if (subscribe) {
             return Balancer.RandomByWeight.selectHost(
                 hostReactor.getServiceInfo(serviceName, StringUtils.join(clusters, ",")));
+        } else {
+            return Balancer.RandomByWeight.selectHost(
+                hostReactor.getServiceInfoDirectlyFromServer(serviceName, StringUtils.join(clusters, ",")));
+        }
     }
 
     @Override
@@ -280,6 +313,23 @@ public class NacosNamingService implements NamingService {
         return serverProxy.serverHealthy() ? "UP" : "DOWN";
     }
 
+    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;
+    }
+
     public BeatReactor getBeatReactor() {
         return beatReactor;
     }

client/src/main/java/com/alibaba/nacos/client/naming/core/HostReactor.java

@@ -16,6 +16,7 @@
 package com.alibaba.nacos.client.naming.core;
 
 import com.alibaba.fastjson.JSON;
+import com.alibaba.nacos.api.exception.NacosException;
 import com.alibaba.nacos.api.naming.pojo.Instance;
 import com.alibaba.nacos.api.naming.pojo.ServiceInfo;
 import com.alibaba.nacos.client.naming.backups.FailoverReactor;
@@ -210,6 +211,14 @@ public class HostReactor {
         return getServiceInfo(serviceName, clusters, env, false);
     }
 
+    public ServiceInfo getServiceInfoDirectlyFromServer(final String serviceName, final String clusters) throws NacosException {
+        String result = serverProxy.queryList(serviceName, clusters, false);
+        if (StringUtils.isNotEmpty(result)) {
+            return JSON.parseObject(result, ServiceInfo.class);
+        }
+        return null;
+    }
+
     public ServiceInfo getServiceInfo(final String serviceName, final String clusters, final String env,
                                       final boolean allIPs) {