聊聊dubbo-go的DubboProtocol

Posted 2021-04-05 码匠的流水账

序

本文主要研究一下dubbo-go的DubboProtocol

DubboProtocol

dubbo-go-v1.4.2/protocol/dubbo/dubbo_protocol.go

// 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
}

• DubboProtocol嵌套了protocol.BaseProtocol，定义了serverMap、serverLock属性

GetProtocol

dubbo-go-v1.4.2/protocol/dubbo/dubbo_protocol.go

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

• GetProtocol方法通过NewDubboProtocol创建dubboProtocol

NewDubboProtocol

dubbo-go-v1.4.2/protocol/dubbo/dubbo_protocol.go

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

• NewDubboProtocol方法实例化了DubboProtocol

Export

dubbo-go-v1.4.2/protocol/dubbo/dubbo_protocol.go

// 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
}

• Export方法通过NewDubboExporter创建exporter，然后更新到DubboProtocol的exporterMap中，之后执行DubboProtocol的openServer

openServer

dubbo-go-v1.4.2/protocol/dubbo/dubbo_protocol.go

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()
 }
}

• openServer方法先根据url.Location从serverMap获取Server，获取不到则执行dp.ExporterMap().Load(url.ServiceKey())，之后再次使用dp.serverMap[url.Location]获取，获取不到则执行NewServer，放到dp.serverMap中，然后执行srv.Start(url)

Refer

dubbo-go-v1.4.2/protocol/dubbo/dubbo_protocol.go

// 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
}

• Refer方法先获取requestTimeout，之后通过NewDubboInvoker创建invoker，然后执行dp.SetInvokers(invoker)

Destroy

dubbo-go-v1.4.2/protocol/dubbo/dubbo_protocol.go

// 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()
 }
}

• Destroy方法先执行dp.BaseProtocol.Destroy()，之后遍历dp.serverMap，执行delete(dp.serverMap, key)及server.Stop()

小结

DubboProtocol嵌套了protocol.BaseProtocol，定义了serverMap、serverLock属性；Export方法通过NewDubboExporter创建exporter，然后更新到DubboProtocol的exporterMap中，之后执行DubboProtocol的openServer；Refer方法先获取requestTimeout，之后通过NewDubboInvoker创建invoker，然后执行dp.SetInvokers(invoker)；Destroy方法先执行dp.BaseProtocol.Destroy()，之后遍历dp.serverMap，执行delete(dp.serverMap, key)及server.Stop()

doc

• dubbo_protocol