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本文次要钻研一下dubbo-go的EchoFilter

EchoFilter

dubbo-go-v1.4.2/filter/filter_impl/echo_filter.go

const (    // ECHO echo module name    ECHO = "echo")func init() {    extension.SetFilter(ECHO, GetFilter)}// EchoFilter// RPCService need a Echo method in consumer, if you want to use EchoFilter// eg://        Echo func(ctx context.Context, arg interface{}, rsp *Xxx) errortype EchoFilter struct{}
  • EchoFilter没有定义属性

Invoke

dubbo-go-v1.4.2/filter/filter_impl/echo_filter.go

// Invoke ...func (ef *EchoFilter) Invoke(ctx context.Context, invoker protocol.Invoker, invocation protocol.Invocation) protocol.Result {    logger.Infof("invoking echo filter.")    logger.Debugf("%v,%v", invocation.MethodName(), len(invocation.Arguments()))    if invocation.MethodName() == constant.ECHO && len(invocation.Arguments()) == 1 {        return &protocol.RPCResult{            Rest:  invocation.Arguments()[0],            Attrs: invocation.Attachments(),        }    }    return invoker.Invoke(ctx, invocation)}
  • Invoke办法判断invocation.MethodName是否是echo，且有一个参数，是的话则返回protocol.RPCResult

OnResponse

dubbo-go-v1.4.2/filter/filter_impl/echo_filter.go

// OnResponse ...func (ef *EchoFilter) OnResponse(_ context.Context, result protocol.Result, _ protocol.Invoker,    _ protocol.Invocation) protocol.Result {    return result}
  • OnResponse办法间接返回result

GetFilter

dubbo-go-v1.4.2/filter/filter_impl/echo_filter.go

// GetFilter ...func GetFilter() filter.Filter {    return &EchoFilter{}}
  • GetFilter办法创立EchoFilter

小结

EchoFilter的Invoke办法判断invocation.MethodName是否是echo，且有一个参数，是的话则返回protocol.RPCResult

doc

  • echo_filter