聊聊nacos-sdk-go的NacosServer

序

本文主要研究一下nacos-sdk-go的NacosServer

NacosServer

nacos-sdk-go-v0.3.2/common/nacos_server/nacos_server.go

type NacosServer struct {
    sync.RWMutex
    securityLogin       security.AuthClient
    serverList          []constant.ServerConfig
    httpAgent           http_agent.IHttpAgent
    timeoutMs           uint64
    endpoint            string
    lastSrvRefTime      int64
    vipSrvRefInterMills int64
}

• NacosServer定义了securityLogin、serverList、httpAgent、timeoutMs、endpoint、lastSrvRefTime、vipSrvRefInterMills属性

NewNacosServer

nacos-sdk-go-v0.3.2/common/nacos_server/nacos_server.go

func NewNacosServer(serverList []constant.ServerConfig, clientCfg constant.ClientConfig, httpAgent http_agent.IHttpAgent, timeoutMs uint64, endpoint string) (NacosServer, error) {
    if len(serverList) == 0 && endpoint == "" {
        return NacosServer{}, errors.New("both serverlist  and  endpoint are empty")
    }

    securityLogin := security.NewAuthClient(clientCfg, serverList, httpAgent)

    ns := NacosServer{
        serverList:          serverList,
        securityLogin:       securityLogin,
        httpAgent:           httpAgent,
        timeoutMs:           timeoutMs,
        endpoint:            endpoint,
        vipSrvRefInterMills: 10000,
    }
    ns.initRefreshSrvIfNeed()
    _, err := securityLogin.Login()

    if err != nil {
        return ns, err
    }

    securityLogin.AutoRefresh()
    return ns, nil
}

• NewNacosServer创建NacosServer及securityLogin，然后执行securityLogin.AutoRefresh()

callConfigServer

nacos-sdk-go-v0.3.2/common/nacos_server/nacos_server.go

func (server *NacosServer) callConfigServer(api string, params map[string]string, newHeaders map[string]string,
    method string, curServer string, contextPath string, timeoutMS uint64) (result string, err error) {
    if contextPath == "" {
        contextPath = constant.WEB_CONTEXT
    }

    signHeaders := getSignHeaders(params, newHeaders)

    url := "http://" + curServer + contextPath + api
    headers := map[string][]string{}
    for k, v := range newHeaders {
        if k != "accessKey" && k != "secretKey" {
            headers[k] = []string{v}
        }
    }
    headers["Client-Version"] = []string{constant.CLIENT_VERSION}
    headers["User-Agent"] = []string{constant.CLIENT_VERSION}
    //headers["Accept-Encoding"] = []string{"gzip,deflate,sdch"}
    headers["Connection"] = []string{"Keep-Alive"}
    headers["exConfigInfo"] = []string{"true"}
    uid, err := uuid.NewV4()
    if err != nil {
        return
    }
    headers["RequestId"] = []string{uid.String()}
    headers["Request-Module"] = []string{"Naming"}
    headers["Content-Type"] = []string{"application/x-www-form-urlencoded;charset=utf-8"}
    headers["Spas-AccessKey"] = []string{newHeaders["accessKey"]}
    headers["Timestamp"] = []string{signHeaders["timeStamp"]}
    headers["Spas-Signature"] = []string{signHeaders["Spas-Signature"]}
    injectSecurityInfo(server, params)

    var response *http.Response
    response, err = server.httpAgent.Request(method, url, headers, timeoutMS, params)
    if err != nil {
        return
    }
    var bytes []byte
    bytes, err = ioutil.ReadAll(response.Body)
    defer response.Body.Close()
    if err != nil {
        return
    }
    result = string(bytes)
    if response.StatusCode == 200 {
        return
    } else {
        err = nacos_error.NewNacosError(strconv.Itoa(response.StatusCode), string(bytes), nil)
        return
    }
}

• callConfigServer方法通过injectSecurityInfo注入SecurityInfo，然后通过server.httpAgent.Request(method, url, headers, timeoutMS, params)执行请求

callServer

nacos-sdk-go-v0.3.2/common/nacos_server/nacos_server.go

func (server *NacosServer) callServer(api string, params map[string]string, method string, curServer string, contextPath string) (result string, err error) {
    if contextPath == "" {
        contextPath = constant.WEB_CONTEXT
    }

    url := "http://" + curServer + contextPath + api
    headers := map[string][]string{}
    headers["Client-Version"] = []string{constant.CLIENT_VERSION}
    headers["User-Agent"] = []string{constant.CLIENT_VERSION}
    //headers["Accept-Encoding"] = []string{"gzip,deflate,sdch"}
    headers["Connection"] = []string{"Keep-Alive"}
    uid, err := uuid.NewV4()
    if err != nil {
        return
    }
    headers["RequestId"] = []string{uid.String()}
    headers["Request-Module"] = []string{"Naming"}
    headers["Content-Type"] = []string{"application/x-www-form-urlencoded;charset=utf-8"}

    injectSecurityInfo(server, params)

    var response *http.Response
    response, err = server.httpAgent.Request(method, url, headers, server.timeoutMs, params)
    if err != nil {
        return
    }
    var bytes []byte
    bytes, err = ioutil.ReadAll(response.Body)
    defer response.Body.Close()
    if err != nil {
        return
    }
    result = string(bytes)
    if response.StatusCode == 200 {
        return
    } else {
        err = errors.New(fmt.Sprintf("request return error code %d", response.StatusCode))
        return
    }
}

• callServer方法通过injectSecurityInfo注入SecurityInfo，通过server.httpAgent.Request(method, url, headers, server.timeoutMs, params)执行请求

ReqConfigApi

nacos-sdk-go-v0.3.2/common/nacos_server/nacos_server.go

func (server *NacosServer) ReqConfigApi(api string, params map[string]string, headers map[string]string, method string, timeoutMS uint64) (string, error) {
    srvs := server.serverList
    if srvs == nil || len(srvs) == 0 {
        return "", errors.New("server list is empty")
    }

    injectSecurityInfo(server, params)

    //only one server,retry request when error
    var err error
    var result string
    if len(srvs) == 1 {
        for i := 0; i < constant.REQUEST_DOMAIN_RETRY_TIME; i++ {
            result, err = server.callConfigServer(api, params, headers, method, getAddress(srvs[0]), srvs[0].ContextPath, timeoutMS)
            if err == nil {
                return result, nil
            }
            log.Printf("[ERROR] api<%s>,method:<%s>, params:<%s>, call domain error:<%s> , result:<%s> /n", api, method, utils.ToJsonString(params), err.Error(), result)
        }
        return "", err
    } else {
        index := rand.Intn(len(srvs))
        for i := 1; i <= len(srvs); i++ {
            curServer := srvs[index]
            result, err = server.callConfigServer(api, params, headers, method, getAddress(curServer), curServer.ContextPath, timeoutMS)
            if err == nil {
                return result, nil
            }
            log.Printf("[ERROR] api<%s>,method:<%s>, params:<%s>, call domain error:<%s> , result:<%s> /n", api, method, utils.ToJsonString(params), err.Error(), result)
            index = (index + i) % len(srvs)
        }
        return "", err
    }
}

• ReqConfigApi方法通过injectSecurityInfo注入SecurityInfo，通过server.callConfigServer执行请求，对于srvs有多个地址的则随机选择一个index执行，执行失败则切换下一个

ReqApi

nacos-sdk-go-v0.3.2/common/nacos_server/nacos_server.go

func (server *NacosServer) ReqApi(api string, params map[string]string, method string) (string, error) {
    srvs := server.serverList
    if srvs == nil || len(srvs) == 0 {
        return "", errors.New("server list is empty")
    }

    injectSecurityInfo(server, params)

    //only one server,retry request when error
    if len(srvs) == 1 {
        for i := 0; i < constant.REQUEST_DOMAIN_RETRY_TIME; i++ {
            result, err := server.callServer(api, params, method, getAddress(srvs[0]), srvs[0].ContextPath)
            if err == nil {
                return result, nil
            }
            log.Printf("[ERROR] api<%s>,method:<%s>, params:<%s>, call domain error:<%s> , result:<%s> /n", api, method, utils.ToJsonString(params), err.Error(), result)
        }
        return "", errors.New("retry " + strconv.Itoa(constant.REQUEST_DOMAIN_RETRY_TIME) + " times request failed!")
    } else {
        index := rand.Intn(len(srvs))
        for i := 1; i <= len(srvs); i++ {
            curServer := srvs[index]
            result, err := server.callServer(api, params, method, getAddress(curServer), curServer.ContextPath)
            if err == nil {
                return result, nil
            }
            log.Printf("[ERROR] api<%s>,method:<%s>, params:<%s>, call domain error:<%s> , result:<%s> /n", api, method, utils.ToJsonString(params), err.Error(), result)
            index = (index + i) % len(srvs)
        }
        return "", errors.New("retry " + strconv.Itoa(constant.REQUEST_DOMAIN_RETRY_TIME) + " times request failed!")
    }
}

• ReqApi方法通过injectSecurityInfo注入SecurityInfo，通过server.callConfigServer执行请求，对于srvs有多个地址的则随机选择一个index执行，执行失败则切换下一个

initRefreshSrvIfNeed

nacos-sdk-go-v0.3.2/common/nacos_server/nacos_server.go

func (server *NacosServer) initRefreshSrvIfNeed() {
    if server.endpoint == "" {
        return
    }
    server.refreshServerSrvIfNeed()
    go func() {
        time.Sleep(time.Duration(1) * time.Second)
        server.refreshServerSrvIfNeed()
    }()

}

• initRefreshSrvIfNeed方法执行server.refreshServerSrvIfNeed()，然后异步执行server.refreshServerSrvIfNeed()

refreshServerSrvIfNeed

nacos-sdk-go-v0.3.2/common/nacos_server/nacos_server.go

func (server *NacosServer) refreshServerSrvIfNeed() {
    if utils.CurrentMillis()-server.lastSrvRefTime < server.vipSrvRefInterMills && len(server.serverList) > 0 {
        return
    }

    var list []string
    urlString := "http://" + server.endpoint + "/nacos/serverlist"
    result := server.httpAgent.RequestOnlyResult(http.MethodGet, urlString, nil, server.timeoutMs, nil)
    list = strings.Split(result, "/n")
    log.Printf("[info] http nacos server list: <%s> /n", result)

    var servers []constant.ServerConfig
    for _, line := range list {
        if line != "" {
            splitLine := strings.Split(strings.TrimSpace(line), ":")
            port := 8848
            var err error
            if len(splitLine) == 2 {
                port, err = strconv.Atoi(splitLine[1])
                if err != nil {
                    log.Printf("[ERROR] get port from server:<%s>  error: <%s> /n", line, err.Error())
                    continue
                }
            }
            servers = append(servers, constant.ServerConfig{IpAddr: splitLine[0], Port: uint64(port), ContextPath: constant.WEB_CONTEXT})
        }
    }
    if len(servers) > 0 {
        if !reflect.DeepEqual(server.serverList, servers) {
            server.Lock()
            log.Printf("[info] server list is updated, old: <%v>,new:<%v> /n", server.serverList, servers)
            server.serverList = servers
            server.lastSrvRefTime = utils.CurrentMillis()
            server.Unlock()
        }

    }

    return
}

• refreshServerSrvIfNeed方法判断距离server.lastSrvRefTime是否超过server.vipSrvRefInterMills，超过则执行请求获取serverlist，然后判断serverList是否变更，变更的话则更新serverList及lastSrvRefTime

GetServerList

nacos-sdk-go-v0.3.2/common/nacos_server/nacos_server.go

func (server *NacosServer) GetServerList() []constant.ServerConfig {
    return server.serverList
}

• GetServerList方法直接返回server.serverList

小结

NacosServer定义了securityLogin、serverList、httpAgent、timeoutMs、endpoint、lastSrvRefTime、vipSrvRefInterMills属性；它提供了NewNacosServer、ReqConfigApi、ReqApi、GetServerList等方法

doc

• nacos_server