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本文次要钻研一下dubbo-go-proxy的timeoutFilter

timeoutFilter

dubbo-go-proxy/pkg/filter/timeout/timeout.go

func Init() {    extension.SetFilterFunc(constant.TimeoutFilter, timeoutFilterFunc(0))}func timeoutFilterFunc(duration time.Duration) fc.FilterFunc {    return New(duration).Do()}// timeoutFilter is a filter for control request time out.type timeoutFilter struct {    // global timeout    waitTime time.Duration}// New create timeout filter.func New(t time.Duration) filter.Filter {    if t <= 0 {        t = constant.DefaultTimeout    }    return &timeoutFilter{        waitTime: t,    }}
timeoutFilter往extension设置了名为`dgp.filters.timeout的timeoutFilterFunc，默认的timeout为1s；timeoutFilterFunc执行的是timeoutFilter的Do办法

Do

dubbo-go-proxy/pkg/filter/timeout/timeout.go

// Do execute timeoutFilter filter logic.func (f timeoutFilter) Do() fc.FilterFunc {    return func(c fc.Context) {        hc := c.(*contexthttp.HttpContext)        ctx, cancel := context.WithTimeout(hc.Ctx, f.getTimeout(hc.Timeout))        defer cancel()        // Channel capacity must be greater than 0.        // Otherwise, if the parent coroutine quit due to timeout,        // the child coroutine may never be able to quit.        finishChan := make(chan struct{}, 1)        go func() {            // panic by recovery            c.Next()            finishChan <- struct{}{}        }()        select {        // timeout do.        case <-ctx.Done():            logger.Warnf("api:%s request timeout", hc.GetAPI().URLPattern)            bt, _ := json.Marshal(filter.ErrResponse{Message: http.ErrHandlerTimeout.Error()})            hc.SourceResp = bt            hc.TargetResp = &client.Response{Data: bt}            hc.WriteJSONWithStatus(http.StatusGatewayTimeout, bt)            c.Abort()        case <-finishChan:            // finish call do something.        }    }}func (f timeoutFilter) getTimeout(t time.Duration) time.Duration {    if t <= 0 {        return f.waitTime    }    return t}
Do办法会通过context.WithTimeout创立ctx及cancel，而后注册defer这个cancel func；之后创立finishChan，异步执行c.Next()，之后往finishChan写入数据；最初select判断ctx.Done()或者是finishChan；如果是ctx.Done()则示意timeout了，返回http.StatusGatewayTimeout

小结

dubbo-go-proxy的timeoutFilter默认设置了1s超时，它通过context.WithTimeout创立ctx及cancel，并异步执行c.Next()，若ctx.Done()则示意timeout了，返回http.StatusGatewayTimeout；若是读取到了finishChan则示意申请失常响应。

doc

  • dubbo-go-proxy