| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.dubbo.rpc.cluster.support.registry; |
| |
| import org.apache.dubbo.common.logger.Logger; |
| import org.apache.dubbo.common.logger.LoggerFactory; |
| import org.apache.dubbo.common.utils.StringUtils; |
| import org.apache.dubbo.rpc.Invocation; |
| import org.apache.dubbo.rpc.Invoker; |
| import org.apache.dubbo.rpc.Result; |
| import org.apache.dubbo.rpc.RpcException; |
| import org.apache.dubbo.rpc.cluster.ClusterInvoker; |
| import org.apache.dubbo.rpc.cluster.Directory; |
| import org.apache.dubbo.rpc.cluster.LoadBalance; |
| import org.apache.dubbo.rpc.cluster.support.AbstractClusterInvoker; |
| import org.apache.dubbo.rpc.cluster.support.wrapper.MockClusterInvoker; |
| |
| import java.util.List; |
| import java.util.stream.Collectors; |
| |
| import static org.apache.dubbo.common.constants.CommonConstants.PREFERRED_KEY; |
| import static org.apache.dubbo.common.constants.RegistryConstants.REGISTRY_ZONE; |
| import static org.apache.dubbo.common.constants.RegistryConstants.REGISTRY_ZONE_FORCE; |
| import static org.apache.dubbo.common.constants.RegistryConstants.ZONE_KEY; |
| |
| /** |
| * When there're more than one registry for subscription. |
| * <p> |
| * This extension provides a strategy to decide how to distribute traffics among them: |
| * 1. registry marked as 'preferred=true' has the highest priority. |
| * 2. check the zone the current request belongs, pick the registry that has the same zone first. |
| * 3. Evenly balance traffic between all registries based on each registry's weight. |
| * 4. Pick anyone that's available. |
| */ |
| public class ZoneAwareClusterInvoker<T> extends AbstractClusterInvoker<T> { |
| |
| private static final Logger logger = LoggerFactory.getLogger(ZoneAwareClusterInvoker.class); |
| |
| public ZoneAwareClusterInvoker(Directory<T> directory) { |
| super(directory); |
| } |
| |
| @Override |
| @SuppressWarnings({"unchecked", "rawtypes"}) |
| public Result doInvoke(Invocation invocation, final List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException { |
| // First, pick the invoker (XXXClusterInvoker) that comes from the local registry, distinguish by a 'preferred' key. |
| for (Invoker<T> invoker : invokers) { |
| ClusterInvoker<T> clusterInvoker = (ClusterInvoker<T>) invoker; |
| if (clusterInvoker.isAvailable() && clusterInvoker.getRegistryUrl() |
| .getParameter(PREFERRED_KEY, false)) { |
| return clusterInvoker.invoke(invocation); |
| } |
| } |
| |
| // providers in the registry with the same zone |
| String zone = invocation.getAttachment(REGISTRY_ZONE); |
| if (StringUtils.isNotEmpty(zone)) { |
| for (Invoker<T> invoker : invokers) { |
| ClusterInvoker<T> clusterInvoker = (ClusterInvoker<T>) invoker; |
| if (clusterInvoker.isAvailable() && zone.equals(clusterInvoker.getRegistryUrl().getParameter(ZONE_KEY))) { |
| return clusterInvoker.invoke(invocation); |
| } |
| } |
| String force = invocation.getAttachment(REGISTRY_ZONE_FORCE); |
| if (StringUtils.isNotEmpty(force) && "true".equalsIgnoreCase(force)) { |
| throw new IllegalStateException("No registry instance in zone or no available providers in the registry, zone: " |
| + zone |
| + ", registries: " + invokers.stream().map(invoker -> ((MockClusterInvoker<T>) invoker).getRegistryUrl().toString()).collect(Collectors.joining(","))); |
| } |
| } |
| |
| |
| // load balance among all registries, with registry weight count in. |
| Invoker<T> balancedInvoker = select(loadbalance, invocation, invokers, null); |
| if (balancedInvoker.isAvailable()) { |
| return balancedInvoker.invoke(invocation); |
| } |
| |
| // If none of the invokers has a preferred signal or is picked by the loadbalancer, pick the first one available. |
| for (Invoker<T> invoker : invokers) { |
| ClusterInvoker<T> clusterInvoker = (ClusterInvoker<T>) invoker; |
| if (clusterInvoker.isAvailable()) { |
| return clusterInvoker.invoke(invocation); |
| } |
| } |
| |
| //if none available,just pick one |
| return invokers.get(0).invoke(invocation); |
| } |
| |
| } |