序

本文主要研究一下dubbo-go-proxy的Client

Client

dubbo-go-proxy/pkg/client/client.go

// Client represents the interface of http/dubbo clients
type Client interface {
    Init() error
    Close() error

    // Call invoke the downstream service.
    Call(req *Request) (res interface{}, err error)

    // MapParams mapping param, uri, query, body ...
    MapParams(req *Request) (reqData interface{}, err error)
}

Client接口定义了Init、Close、Call、MapParams方法

Client

dubbo-go-proxy/pkg/client/dubbo/dubbo.go

// Client client to generic invoke dubbo
type Client struct {
    lock               sync.RWMutex
    GenericServicePool map[string]*dg.GenericService
}

Client定义了lock、GenericServicePool属性，它实现了Client接口

Init

dubbo-go-proxy/pkg/client/dubbo/dubbo.go

// Init init dubbo, config mapping can do here
func (dc *Client) Init() error {
    dc.GenericServicePool = make(map[string]*dg.GenericService, 4)

    cls := config.GetBootstrap().StaticResources.Clusters

    // dubbogo comsumer config
    dgCfg = dg.ConsumerConfig{
        Check:      new(bool),
        Registries: make(map[string]*dg.RegistryConfig, 4),
    }
    dgCfg.ApplicationConfig = defaultApplication
    for i := range cls {
        c := cls[i]
        dgCfg.Request_Timeout = c.RequestTimeoutStr
        dgCfg.Connect_Timeout = c.ConnectTimeoutStr
        for k, v := range c.Registries {
            if len(v.Protocol) == 0 {
                logger.Warnf("can not find registry protocol config, use default type 'zookeeper'")
                v.Protocol = defaultDubboProtocol
            }
            dgCfg.Registries[k] = &dg.RegistryConfig{
                Protocol:   v.Protocol,
                Address:    v.Address,
                TimeoutStr: v.Timeout,
                Username:   v.Username,
                Password:   v.Password,
            }
        }
    }

    initDubbogo()

    return nil
}

func initDubbogo() {
    dg.SetConsumerConfig(dgCfg)
    dg.Load()
}

Init方法主要是构建ConsumerConfig，然后执行initDubbogo

Close

dubbo-go-proxy/pkg/client/dubbo/dubbo.go

// Close clear GenericServicePool.
func (dc *Client) Close() error {
    dc.lock.Lock()
    defer dc.lock.Unlock()
    for k := range dc.GenericServicePool {
        delete(dc.GenericServicePool, k)
    }
    return nil
}

Close方法通过加锁遍历dc.GenericServicePool执行delete操作

Call

dubbo-go-proxy/pkg/client/dubbo/dubbo.go

// Call invoke service
func (dc *Client) Call(req *client.Request) (res interface{}, err error) {
    types, values, err := dc.genericArgs(req)
    if err != nil {
        return nil, err
    }

    dm := req.API.Method.IntegrationRequest
    method := dm.Method

    logger.Debugf("[dubbo-go-proxy] dubbo invoke, method:%s, types:%s, reqData:%v", method, types, values)

    gs := dc.Get(dm)

    rst, err := gs.Invoke(req.Context, []interface{}{method, types, values})

    if err != nil {
        return nil, err
    }

    logger.Debugf("[dubbo-go-proxy] dubbo client resp:%v", rst)

    return rst, nil
}

Call方法通过dc.Get(dm)获取GenericService，然后通过GenericService.Invoke进行请求

MapParams

dubbo-go-proxy/pkg/client/dubbo/dubbo.go

// MapParams params mapping to api.
func (dc *Client) MapParams(req *client.Request) (interface{}, error) {
    r := req.API.Method.IntegrationRequest
    if len(r.ParamTypes) != len(r.MappingParams) {
        return nil, errors.New("Numbers of param types and paramMappings are not the same")
    }
    var values []interface{}
    for _, mappingParam := range r.MappingParams {
        source, _, err := client.ParseMapSource(mappingParam.Name)
        if err != nil {
            return nil, err
        }
        if mapper, ok := mappers[source]; ok {
            if err := mapper.Map(mappingParam, req, &values, buildOption(mappingParam)); err != nil {
                return nil, err
            }
        }
    }
    return values, nil
}

MapParams方法遍历MappingParams，通过client.ParseMapSource获取source，再通过mappers[source]获取mapper，最后通过mapper的Map方法进行转换

小结

dubbo-go-proxy的client.Client接口定义了Init、Close、Call、MapParams方法；其dubbo.Client实现了client.Client接口；其主要是通过mapper进行参数转换，然后通过GenericService.Invoke进行请求。

doc

• dubbo-go-proxy