序

本文主要研究一下dubbo-go-proxy的ConsulRegistryLoad

Loader

dubbo-go-proxy/pkg/registry/load.go

// Loader this interface defined for load services from different kinds registry, such as nacos,consul,zookeeper.
type Loader interface {
    // LoadAllServices load all services registered in registry
    LoadAllServices() ([]*common.URL, error)
    // GetCluster get the registry name
    GetCluster() (string, error)
}

Loader接口定义了LoadAllServices、GetCluster方法

ConsulRegistryLoad

dubbo-go-proxy/pkg/registry/consul.go

func init() {
    var _ Loader = new(ConsulRegistryLoad)
}

const (
    dubboAPIFilter = "dubbo in Tags"
)

// ConsulRegistryLoad load dubbo apis from consul registry
type ConsulRegistryLoad struct {
    Address string
    // Consul client.
    client  *consul.Client
    cluster string
}

func newConsulRegistryLoad(address, cluster string) (Loader, error) {
    config := &consul.Config{Address: address}
    client, err := consul.NewClient(config)
    if err != nil {
        return nil, err
    }

    r := &ConsulRegistryLoad{
        Address: address,
        client:  client,
        cluster: cluster,
    }

    return r, nil
}

ConsulRegistryLoad定义了Address、client、cluster属性；newConsulRegistryLoad方法根据address及cluster来创建ConsulRegistryLoad

GetCluster

dubbo-go-proxy/pkg/registry/consul.go

func (crl *ConsulRegistryLoad) GetCluster() (string, error) {
    return crl.cluster, nil
}

GetCluster方法返回ConsulRegistryLoad的cluster属性

LoadAllServices

dubbo-go-proxy/pkg/registry/consul.go

func (crl *ConsulRegistryLoad) LoadAllServices() ([]*common.URL, error) {
    agentServices, err := crl.client.Agent().ServicesWithFilter(dubboAPIFilter)
    if err != nil {
        logger.Error("consul load all apis error:%v", err)
        return nil, perrors.Wrap(err, "consul load all apis")
    }
    var urls []*common.URL
    for _, service := range agentServices {
        url, err := crl.transfer2Url(*service)
        if err != nil {
            logger.Warnf("consul transfer service to url error:%v", err)
            continue
        }
        urls = append(urls, url)
    }
    return urls, nil
}

LoadAllServices方法通过ConsulRegistryLoad的client.Agent().ServicesWithFilter来获取agentServices，之后遍历agentServices通过transfer2Url方法转换为url

transfer2Url

dubbo-go-proxy/pkg/registry/consul.go

func (crl *ConsulRegistryLoad) transfer2Url(service consul.AgentService) (*common.URL, error) {
    var params = url.Values{}
    var protocol string

    for _, tag := range service.Tags {
        kv := strings.Split(tag, "=")
        if len(kv) != 2 {
            continue
        }
        params.Add(kv[0], kv[1])
    }

    if url, ok := service.Meta["url"]; ok {
        protocol = strings.Split(url, ":")[0]
    }

    methodsParam := strings.Split(params.Get(constant.METHODS_KEY), ",")
    var methods = make([]string, len(methodsParam))
    for _, method := range methodsParam {
        if method != "" {
            methods = append(methods, method)
        }
    }
    url := common.NewURLWithOptions(common.WithPort(strconv.Itoa(service.Port)),
        common.WithProtocol(protocol), common.WithMethods(methods),
        common.WithIp(service.Address), common.WithParams(params))

    return url, nil
}

transfer2Url方法遍历service.Tags追加到params，之后解析service.Meta["url"]，再解析params.Get(constant.METHODS_KEY)，最后通过common.NewURLWithOptions构建url

小结

ConsulRegistryLoad定义了Address、client、cluster属性；newConsulRegistryLoad方法根据address及cluster来创建ConsulRegistryLoad；它实现了Loader接口，提供了GetCluster、LoadAllServices方法。

doc

• dubbo-go-proxy