聊聊dubbo-go的DubboProtocol

// dubbo protocol constant
const (
    // DUBBO ...
    DUBBO = "dubbo"
)
​
func init() {
    extension.SetProtocol(DUBBO, GetProtocol)
}
​
var (
    dubboProtocol *DubboProtocol
)
​
// DubboProtocol ...
type DubboProtocol struct {
    protocol.BaseProtocol
    serverMap  map[string]*Server
    serverLock sync.Mutex
}

// GetProtocol ...
func GetProtocol() protocol.Protocol {
    if dubboProtocol == nil {
        dubboProtocol = NewDubboProtocol()
    }
    return dubboProtocol
}

// NewDubboProtocol ...
func NewDubboProtocol() *DubboProtocol {
    return &DubboProtocol{
        BaseProtocol: protocol.NewBaseProtocol(),
        serverMap:    make(map[string]*Server),
    }
}

// Export ...
func (dp *DubboProtocol) Export(invoker protocol.Invoker) protocol.Exporter {
    url := invoker.GetUrl()
    serviceKey := url.ServiceKey()
    exporter := NewDubboExporter(serviceKey, invoker, dp.ExporterMap())
    dp.SetExporterMap(serviceKey, exporter)
    logger.Infof("Export service: %s", url.String())
​
    // start server
    dp.openServer(url)
    return exporter
}

func (dp *DubboProtocol) openServer(url common.URL) {
    _, ok := dp.serverMap[url.Location]
    if !ok {
        _, ok := dp.ExporterMap().Load(url.ServiceKey())
        if !ok {
            panic("[DubboProtocol]" + url.Key() + "is not existing")
        }
​
        dp.serverLock.Lock()
        _, ok = dp.serverMap[url.Location]
        if !ok {
            srv := NewServer()
            dp.serverMap[url.Location] = srv
            srv.Start(url)
        }
        dp.serverLock.Unlock()
    }
}

// Refer ...
func (dp *DubboProtocol) Refer(url common.URL) protocol.Invoker {
    //default requestTimeout
    var requestTimeout = config.GetConsumerConfig().RequestTimeout
​
    requestTimeoutStr := url.GetParam(constant.TIMEOUT_KEY, config.GetConsumerConfig().Request_Timeout)
    if t, err := time.ParseDuration(requestTimeoutStr); err == nil {
        requestTimeout = t
    }
​
    invoker := NewDubboInvoker(url, NewClient(Options{
        ConnectTimeout: config.GetConsumerConfig().ConnectTimeout,
        RequestTimeout: requestTimeout,
    }))
    dp.SetInvokers(invoker)
    logger.Infof("Refer service: %s", url.String())
    return invoker
}

// Destroy ...
func (dp *DubboProtocol) Destroy() {
    logger.Infof("DubboProtocol destroy.")
​
    dp.BaseProtocol.Destroy()
​
    // stop server
    for key, server := range dp.serverMap {
        delete(dp.serverMap, key)
        server.Stop()
    }
}