聊聊kingbus的binlogsyncerhandlergo

序

本文主要研究一下 kingbus 的 binlog_syncer_handler.go

StartBinlogSyncer

kingbus/api/binlog_syncer_handler.go

//StartBinlogSyncer implements start a binlog syncer
func (h *BinlogSyncerHandler) StartBinlogSyncer(echoCtx echo.Context) error {h.l.Lock()
    defer h.l.Unlock()

    var args config.SyncerArgs
    var err error
    var syncerID int

    defer func() {
        if err != nil {log.Log.Errorf("StartBinlogSyncer error,err: %s", err)
            echoCtx.JSON(http.StatusInternalServerError, utils.NewResp().SetError(err.Error()))
        }
    }()

    err = echoCtx.Bind(&args)
    if err != nil {return err}
    //check args
    err = args.Check()
    if err != nil {return err}

    //forward to leader
    if h.svr.IsLeader() == false {req, err := json.Marshal(args)
        if err != nil {return echoCtx.JSON(http.StatusInternalServerError, utils.NewResp().SetError(err.Error()))
        }
        resp, err := h.sendToLeader("PUT", "/binlog/syncer/start", req)
        if err != nil {log.Log.Errorf("sendToLeader error,err:%s,args:%v", err, args)
            return echoCtx.JSON(http.StatusInternalServerError, utils.NewResp().SetError(err.Error()))
        }
        if resp.Message != "success" {return echoCtx.JSON(http.StatusInternalServerError, utils.NewResp().SetError(resp.Message))
        }
        return echoCtx.JSON(http.StatusOK, utils.NewResp().SetData(resp.Data))
    }

    //start syncer server
    err = h.svr.StartServer(config.SyncerServerType, &args)
    if err != nil {log.Log.Errorf("StartServer error,err:%s,args:%v", err, args)
        return err
    }

    //propose start syncer info
    err = h.ProposeSyncerArgs(&args)
    if err != nil {log.Log.Errorf("ProposeSyncerArgs error,err:%s,args:%v", err, args)
        return err
    }

    return echoCtx.JSON(http.StatusOK, utils.NewResp().SetData(syncerID))
}

• StartBinlogSyncer 方法先执行 echoCtx.Bind(&args)，然后针对 h.svr.IsLeader()为 false 的通过 h.sendToLeader(“PUT”, “/binlog/syncer/start”, req)将请求转发给 leader；为 true 的则执行 h.svr.StartServer(config.SyncerServerType, &args)启动 syncer server，然后执行 h.ProposeSyncerArgs(&args)启动 propose syncer

StopBinlogSyncer

kingbus/api/binlog_syncer_handler.go

//StopBinlogSyncer implements stop binlog syncer
func (h *BinlogSyncerHandler) StopBinlogSyncer(echoCtx echo.Context) error {h.l.Lock()
    defer h.l.Unlock()

    //forward to leader
    if h.svr.IsLeader() == false {resp, err := h.sendToLeader("PUT", "/binlog/syncer/stop", nil)
        if err != nil {log.Log.Errorf("sendToLeader error,err:%s", err)
            return echoCtx.JSON(http.StatusInternalServerError, utils.NewResp().SetError(err.Error()))
        }
        if resp.Message != "success" {return echoCtx.JSON(http.StatusInternalServerError, utils.NewResp().SetError(resp.Message))
        }
        return echoCtx.JSON(http.StatusOK, utils.NewResp().SetData(resp.Data))
    }

    h.svr.StopServer(config.SyncerServerType)
    return echoCtx.JSON(http.StatusOK, utils.NewResp().SetData(""))
}

• StopBinlogSyncer 方法对于 h.svr.IsLeader()为 false 的通过 h.sendToLeader(“PUT”, “/binlog/syncer/stop”, nil)将请求转发给 leader；为 true 的则执行 h.svr.StopServer(config.SyncerServerType)

GetBinlogSyncerStatus

kingbus/api/binlog_syncer_handler.go

//GetBinlogSyncerStatus implements get binlog syncer status in the runtime state
func (h *BinlogSyncerHandler) GetBinlogSyncerStatus(echoCtx echo.Context) error {h.l.Lock()
    defer h.l.Unlock()

    //forward to leader
    if h.svr.IsLeader() == false {resp, err := h.sendToLeader("GET", "/binlog/syncer/status", nil)
        if err != nil {log.Log.Errorf("sendToLeader error,err:%s", err)
            return echoCtx.JSON(http.StatusInternalServerError, utils.NewResp().SetError(err.Error()))
        }
        if resp.Message != "success" {return echoCtx.JSON(http.StatusInternalServerError, utils.NewResp().SetError(resp.Message))
        }
        return echoCtx.JSON(http.StatusOK, utils.NewResp().SetData(resp.Data))
    }

    status := h.svr.GetServerStatus(config.SyncerServerType)
    if syncerStatus, ok := status.(*config.SyncerStatus); ok {return echoCtx.JSON(http.StatusOK, utils.NewResp().SetData(syncerStatus))
    }
    return echoCtx.JSON(http.StatusInternalServerError, utils.NewResp().SetError("no resp"))
}

• GetBinlogSyncerStatus 方法对于 h.svr.IsLeader()为 false 的通过 h.sendToLeader(“GET”, “/binlog/syncer/status”, nil)方法转发给 leader；为 true 的则执行 h.svr.GetServerStatus(config.SyncerServerType)获取 status

sendToLeader

kingbus/api/membership_handler.go

func (h *MembershipHandler) sendToLeader(method string, req []byte) (*utils.Resp, error) {leaderID := h.svr.Leader()
    leader := h.cluster.Member(leaderID)
    if leader == nil {return nil, ErrNoLeader}
    if len(leader.AdminURLs) != 1 {log.Log.Errorf("leader admin url is not 1,leader:%v", *leader)
        return nil, ErrNoLeader
    }
    leaderURL, err := url.Parse(leader.AdminURLs[0])
    if err != nil {return nil, err}
    url := leaderURL.Scheme + "://" + leaderURL.Host + "/members"

    resp, err := utils.SendRequest(method, url, req)
    if err != nil {log.Log.Errorf("sendToLeader:SendRequest error,err:%s,url:%s", err, url)
        return nil, err
    }

    return resp, nil
}

• sendToLeader 方法通过 h.svr.Leader()获取 leaderId，然后执行 h.cluster.Member(leaderID)获取 leader，之后构造 leaderURL，然后执行 utils.SendRequest(method, url, req)发送请求

SendRequest

kingbus/utils/http_utils.go

//SendRequest send PUT request to leader
func SendRequest(method string, leaderURL string, data []byte) (*Resp, error) {client := &http.Client{}
    req, err := http.NewRequest(method, leaderURL, bytes.NewBuffer(data))
    if err != nil {return nil, err}
    req.Header.Set("Content-Type", "application/json;charset=utf-8")

    resp, err := client.Do(req)
    if err != nil {return nil, err}
    defer resp.Body.Close()

    respBody, err := ioutil.ReadAll(resp.Body)
    if err != nil {return nil, err}

    r := new(Resp)
    err = json.Unmarshal(respBody, r)
    if err != nil {return nil, err}

    return r, nil
}

• SendRequest 通过 http.NewRequest 构建 request，其 contentType 为 application/json;charset=utf-8，之后通过 client.Do(req) 发送请求，然后通过 ioutil.ReadAll(resp.Body)读取 respBody，在通过 json.Unmarshal(respBody, r)解析 json 为 Resp 类型

小结

kingbus 的 binlog_syncer_handler.go 提供了 StartBinlogSyncer、StopBinlogSyncer、GetBinlogSyncerStatus 方法

doc

• binlog_syncer_handler