Merge pull request #720 from eacdy/master

Add NacosRule support weight rule

spring-cloud-alibaba-nacos-discovery/src/main/java/org/springframework/cloud/alibaba/nacos/ribbon/ExtendBalancer.java

@@ -0,0 +1,21 @@
+package org.springframework.cloud.alibaba.nacos.ribbon;
+
+import com.alibaba.nacos.api.naming.pojo.Instance;
+import com.alibaba.nacos.client.naming.core.Balancer;
+
+import java.util.List;
+
+/**
+ * @author itmuch.com
+ */
+public class ExtendBalancer extends Balancer {
+    /**
+     * 根据权重，随机选择实例
+     *
+     * @param instances 实例列表
+     * @return 选择的实例
+     */
+    public static Instance getHostByRandomWeight2(List<Instance> instances) {
+        return getHostByRandomWeight(instances);
+    }
+}

spring-cloud-alibaba-nacos-discovery/src/main/java/org/springframework/cloud/alibaba/nacos/ribbon/NacosRule.java

@@ -0,0 +1,69 @@
+package org.springframework.cloud.alibaba.nacos.ribbon;
+
+import com.alibaba.nacos.api.naming.NamingService;
+import com.alibaba.nacos.api.naming.pojo.Instance;
+import com.netflix.client.config.IClientConfig;
+import com.netflix.loadbalancer.AbstractLoadBalancerRule;
+import com.netflix.loadbalancer.DynamicServerListLoadBalancer;
+import com.netflix.loadbalancer.Server;
+import org.apache.commons.lang3.StringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.cloud.alibaba.nacos.NacosDiscoveryProperties;
+import org.springframework.util.CollectionUtils;
+
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+/**
+ * 支持优先调用同集群实例的ribbon负载均衡规则.
+ *
+ * @author itmuch.com
+ */
+public class NacosRule extends AbstractLoadBalancerRule {
+    private static final Logger LOGGER = LoggerFactory.getLogger(NacosRule.class);
+
+    @Autowired
+    private NacosDiscoveryProperties nacosDiscoveryProperties;
+
+    @Override
+    public Server choose(Object key) {
+        try {
+            String clusterName = this.nacosDiscoveryProperties.getClusterName();
+            DynamicServerListLoadBalancer loadBalancer = (DynamicServerListLoadBalancer) getLoadBalancer();
+            String name = loadBalancer.getName();
+
+            NamingService namingService = this.nacosDiscoveryProperties.namingServiceInstance();
+            List<Instance> instances = namingService.selectInstances(name, true);
+            if (CollectionUtils.isEmpty(instances)) {
+                LOGGER.warn("{}服务当前无任何实例", name);
+                return null;
+            }
+
+            List<Instance> instancesToChoose = instances;
+            if (StringUtils.isNotBlank(clusterName)) {
+                List<Instance> sameClusterInstances = instances.stream()
+                        .filter(instance -> Objects.equals(clusterName, instance.getClusterName()))
+                        .collect(Collectors.toList());
+                if (!CollectionUtils.isEmpty(sameClusterInstances)) {
+                    instancesToChoose = sameClusterInstances;
+                } else {
+                    LOGGER.warn("发生跨集群的调用，name = {}, clusterName = {}, instance = {}", name, clusterName, instances);
+                }
+            }
+
+            Instance instance = ExtendBalancer.getHostByRandomWeight2(instancesToChoose);
+
+            return new NacosServer(instance);
+        } catch (Exception e) {
+            LOGGER.warn("NacosRule发生异常", e);
+            return null;
+        }
+    }
+
+    @Override
+    public void initWithNiwsConfig(IClientConfig iClientConfig) {
+    }
+}