dubbo源码分析第十六篇一dubbo集群容错策略-BroadcastCluster广播_dubbo broadcast cluster

前言

cluster可选策略

mock=org.apache.dubbo.rpc.cluster.support.wrapper.MockClusterWrapper
failover=org.apache.dubbo.rpc.cluster.support.FailoverCluster
failfast=org.apache.dubbo.rpc.cluster.support.FailfastCluster
failsafe=org.apache.dubbo.rpc.cluster.support.FailsafeCluster
failback=org.apache.dubbo.rpc.cluster.support.FailbackCluster
forking=org.apache.dubbo.rpc.cluster.support.ForkingCluster
available=org.apache.dubbo.rpc.cluster.support.AvailableCluster
mergeable=org.apache.dubbo.rpc.cluster.support.MergeableCluster
broadcast=org.apache.dubbo.rpc.cluster.support.BroadcastCluster
zone-aware=org.apache.dubbo.rpc.cluster.support.registry.ZoneAwareCluster

BroadcastCluster作用

• 构建BroadcastClusterInvoker
• 广播调用,即使其中一个Invoker执行异常也不会终止广播

BroadcastCluster

• 负责创建广播调用Invoker

public class BroadcastCluster extends AbstractCluster {
    @Override
    public <T> AbstractClusterInvoker<T> doJoin(Directory<T> directory) throws RpcException {
        return new BroadcastClusterInvoker<>(directory);
    }

}
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BroadcastClusterInvoker

• 遍历所有Invoker,进行广播调用

public class BroadcastClusterInvoker<T> extends AbstractClusterInvoker<T> {
    @Override
    @SuppressWarnings({"unchecked", "rawtypes"})
    public Result doInvoke(final Invocation invocation, List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
        RpcException exception = null;
        Result result = null;
        广播调用,吞噬异常
        for (Invoker<T> invoker : invokers) {
            try {
                result = invoker.invoke(invocation);
            } catch (RpcException e) {
                exception = e;
                logger.warn(e.getMessage(), e);
            } catch (Throwable e) {
                exception = new RpcException(e.getMessage(), e);
                logger.warn(e.getMessage(), e);
            }
        }
        广播完毕后,有exception,则抛出异常
        if (exception != null) {
            throw exception;
        }
        return result;
    }

}

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