关于dubbo:聊聊dubbogo的broadcastCluster

序

本文次要钻研一下 dubbo-go 的 broadcastCluster

broadcastCluster

dubbo-go-v1.4.2/cluster/cluster_impl/broadcast_cluster.go

type broadcastCluster struct{}

const broadcast = "broadcast"

func init() {extension.SetCluster(broadcast, NewBroadcastCluster)
}

// NewBroadcastCluster ...
func NewBroadcastCluster() cluster.Cluster {return &broadcastCluster{}
}

func (cluster *broadcastCluster) Join(directory cluster.Directory) protocol.Invoker {return newBroadcastClusterInvoker(directory)
}

• broadcastCluster 的 join 办法执行 newBroadcastClusterInvoker

newBroadcastClusterInvoker

dubbo-go-v1.4.2/cluster/cluster_impl/broadcast_cluster_invoker.go

type broadcastClusterInvoker struct {baseClusterInvoker}

func newBroadcastClusterInvoker(directory cluster.Directory) protocol.Invoker {
    return &broadcastClusterInvoker{baseClusterInvoker: newBaseClusterInvoker(directory),
    }
}

• newBroadcastClusterInvoker 办法实例化 broadcastClusterInvoker

Invoke

dubbo-go-v1.4.2/cluster/cluster_impl/broadcast_cluster_invoker.go

func (invoker *broadcastClusterInvoker) Invoke(ctx context.Context, invocation protocol.Invocation) protocol.Result {invokers := invoker.directory.List(invocation)
    err := invoker.checkInvokers(invokers, invocation)
    if err != nil {return &protocol.RPCResult{Err: err}
    }
    err = invoker.checkWhetherDestroyed()
    if err != nil {return &protocol.RPCResult{Err: err}
    }

    var result protocol.Result
    for _, ivk := range invokers {result = ivk.Invoke(ctx, invocation)
        if result.Error() != nil {logger.Warnf("broadcast invoker invoke err: %v when use invoker: %v\n", result.Error(), ivk)
            err = result.Error()}
    }
    if err != nil {return &protocol.RPCResult{Err: err}
    }
    return result
}

• Invoke 办法首先通过 invoker.directory.List(invocation) 获取 invokers，之后遍历 invokers，挨个执行 result = ivk.Invoke(ctx, invocation)，如果最初 err 不为 nil，则返回 err，否则返回最初的 result

小结

broadcastCluster 的 join 办法执行 newBroadcastClusterInvoker；其 Invoke 办法首先通过 invoker.directory.List(invocation) 获取 invokers，之后遍历 invokers，挨个执行 result = ivk.Invoke(ctx, invocation)，如果最初 err 不为 nil，则返回 err，否则返回最初的 result

doc

• broadcast_cluster