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filecoin技术架构分析之五:filecoin源码分析之协议

filecoin技术架构分析之五:filecoin源码分析之协议

作者: 杨尉 | 来源:发表于2019-03-04 16:04 被阅读10次

    本文作者:先河系统杨尉;原创作品,转载请注明出处

    目录

    5.1 源码信息

    • version
      • master分支 619b0eb1(2019年3月2日)
    • package
      • metrics
    • location
      • metrics/heartbeat.go
      • node/node.go

    5.2 源码分析

    5.2.1 数据结构

    • 定义心跳协议名称以及连接超时时间
    // HeartbeatProtocol is the libp2p protocol used for the heartbeat service
    const (
        HeartbeatProtocol = "fil/heartbeat/1.0.0"
        // Minutes to wait before logging connection failure at ERROR level
        connectionFailureErrorLogPeriodMinutes = 10 * time.Minute
    )
    
    • 定义心跳信息结构
      • 节点的区块头
      • 节点的区块高度
      • 节点的昵称
      • 是否在区块同步中(TODO)
      • 矿工地址(如果没有挖矿,这里为零地址)
    // Heartbeat contains the information required to determine the current state of a node.
    // Heartbeats are used for aggregating information about nodes in a log aggregator
    // to support alerting and devnet visualization.
    type Heartbeat struct {
        // Head represents the heaviest tipset the nodes is mining on
        Head string
        // Height represents the current height of the Tipset
        Height uint64
        // Nickname is the nickname given to the filecoin node by the user
        Nickname string
        // TODO: add when implemented
        // Syncing is `true` iff the node is currently syncing its chain with the network.
        // Syncing bool
    
        // Address of this node's active miner. Can be empty - will return the zero address
        MinerAddress address.Address
    }
    
    • 心跳服务结构体
      • 主机结构体:对应libp2p主机
      • 心跳配置
      • 区块头获取
      • 挖矿地址获取
      • stream锁
      • stream
    // HeartbeatService is responsible for sending heartbeats.
    type HeartbeatService struct {
        Host   host.Host
        Config *config.HeartbeatConfig
    
        // A function that returns the heaviest tipset
        HeadGetter func() types.TipSet
    
        // A function that returns the miner's address
        MinerAddressGetter func() address.Address
    
        streamMu sync.Mutex
        stream   net.Stream
    }
    
    • 定义心跳服务Option函数
      • 函数入参为心跳服务结构体,主要用于对心跳服务结构体传参或者解析
    // HeartbeatServiceOption is the type of the heartbeat service's functional options.
    type HeartbeatServiceOption func(service *HeartbeatService)
    

    5.2.2 方法

    • 获取心跳服务的stream实例
    // Stream returns the HeartbeatService stream. Safe for concurrent access.
    // Stream is a libp2p connection that heartbeat messages are sent over to an aggregator.
    func (hbs *HeartbeatService) Stream() net.Stream {
        hbs.streamMu.Lock()
        defer hbs.streamMu.Unlock()
        return hbs.stream
    }
    
    • 设置心跳服务的stream实例
    // SetStream sets the stream on the HeartbeatService. Safe for concurrent access.
    func (hbs *HeartbeatService) SetStream(s net.Stream) {
        hbs.streamMu.Lock()
        defer hbs.streamMu.Unlock()
        hbs.stream = s
    }
    
    • 定时确认连接性,并调用运行心跳服务
    // Start starts the heartbeat service by, starting the connection loop. The connection
    // loop will attempt to connected to the aggregator service, once a successful
    // connection is made with the aggregator service hearbeats will be sent to it.
    // If the connection is broken the heartbeat service will attempt to reconnect via
    // the connection loop. Start will not return until context `ctx` is 'Done'.
    func (hbs *HeartbeatService) Start(ctx context.Context) {
        log.Debug("starting heartbeat service")
    
        rd, err := time.ParseDuration(hbs.Config.ReconnectPeriod)
        if err != nil {
            log.Errorf("invalid heartbeat reconnectPeriod: %s", err)
            return
        }
    
        //启动重连定时器
        reconTicker := time.NewTicker(rd)
        defer reconTicker.Stop()
        // Timestamp of the first connection failure since the last successful connection.
        // Zero initially and while connected.
        var failedAt time.Time
        // Timestamp of the last ERROR log (or of failure, before the first ERROR log).
        var erroredAt time.Time
        for {
            select {
            case <-ctx.Done():
                return
            case <-reconTicker.C:
                //重连定时周期到,重新连接
                if err := hbs.Connect(ctx); err != nil {
                    // Logs once as a warning immediately on failure, then as error every 10 minutes.
                    now := time.Now()
                    logfn := log.Debugf
                    if failedAt.IsZero() { // First failure since connection
                        failedAt = now
                        erroredAt = failedAt // Start the timer on raising to ERROR level
                        logfn = log.Warningf
                    } else if now.Sub(erroredAt) > connectionFailureErrorLogPeriodMinutes {
                        logfn = log.Errorf
                        erroredAt = now // Reset the timer
                    }
                    failureDuration := now.Sub(failedAt)
                    logfn("Heartbeat service failed to connect for %s: %s", failureDuration, err)
                    // failed to connect, continue reconnect loop
                    continue
                }
                failedAt = time.Time{}
    
                // we connected, send heartbeats!
                // Run will block until it fails to send a heartbeat.
                //如果连接成功,运行心跳服务
                if err := hbs.Run(ctx); err != nil {
                    log.Warning("disconnecting from aggregator, failed to send heartbeat")
                    continue
                }
            }
        }
    }
    
    • 运行心跳服务
    // Run is called once the heartbeat service connects to the aggregator. Run
    // send the actual heartbeat. Run will block until `ctx` is 'Done`. An error will
    // be returned if Run encounters an error when sending the heartbeat and the connection
    // to the aggregator will be closed.
    func (hbs *HeartbeatService) Run(ctx context.Context) error {
        bd, err := time.ParseDuration(hbs.Config.BeatPeriod)
        if err != nil {
            log.Errorf("invalid heartbeat beatPeriod: %s", err)
            return err
        }
    
        //启动心跳定时器
        beatTicker := time.NewTicker(bd)
        defer beatTicker.Stop()
    
        //通过encoder进行流写入
        // TODO use cbor instead of json
        encoder := json.NewEncoder(hbs.stream)
        for {
            select {
            case <-ctx.Done():
                return nil
            case <-beatTicker.C:
            //心跳定时周期到,调用Beat方法获取心跳参数
                hb := hbs.Beat()
                //写入流,发起心跳
                if err := encoder.Encode(hb); err != nil {
                    //发生错误会关闭流连接
                    hbs.stream.Conn().Close() // nolint: errcheck
                    return err
                }
            }
        }
    }
    
    • 获取心跳参数
    // Beat will create a heartbeat.
    func (hbs *HeartbeatService) Beat() Heartbeat {
        nick := hbs.Config.Nickname
        ts := hbs.HeadGetter()
        tipset := ts.ToSortedCidSet().String()
        height, err := ts.Height()
        if err != nil {
            log.Warningf("heartbeat service failed to get chain height: %s", err)
        }
        addr := hbs.MinerAddressGetter()
        return Heartbeat{
            Head:         tipset,
            Height:       height,
            Nickname:     nick,
            MinerAddress: addr,
        }
    }
    
    • 心跳流连接
    // Connect will connects to `hbs.Config.BeatTarget` or returns an error
    func (hbs *HeartbeatService) Connect(ctx context.Context) error {
        log.Debugf("Heartbeat service attempting to connect, targetAddress: %s", hbs.Config.BeatTarget)
        targetMaddr, err := ma.NewMultiaddr(hbs.Config.BeatTarget)
        if err != nil {
            return err
        }
    
        pid, err := targetMaddr.ValueForProtocol(ma.P_P2P)
        if err != nil {
            return err
        }
    
        peerid, err := peer.IDB58Decode(pid)
        if err != nil {
            return err
        }
    
        // Decapsulate the /p2p/<peerID> part from the target
        // /ip4/<a.b.c.d>/p2p/<peer> becomes /ip4/<a.b.c.d>
        targetPeerAddr, _ := ma.NewMultiaddr(
            fmt.Sprintf("/p2p/%s", peer.IDB58Encode(peerid)))
        targetAddr := targetMaddr.Decapsulate(targetPeerAddr)
    
        hbs.Host.Peerstore().AddAddr(peerid, targetAddr, pstore.PermanentAddrTTL)
    
        // 建立心跳服务流
        s, err := hbs.Host.NewStream(ctx, peerid, HeartbeatProtocol)
        if err != nil {
            log.Debugf("failed to open stream, peerID: %s, targetAddr: %s %s", peerid, targetAddr, err)
            return err
        }
        log.Infof("successfully to open stream, peerID: %s, targetAddr: %s", peerid, targetAddr)
    
        //设置流函数
        hbs.SetStream(s)
        return nil
    }
    

    5.2.3 函数

    • 向心跳服务结构体传参,用于设置获取矿工地址函数
    // WithMinerAddressGetter returns an option that can be used to set the miner address getter.
    func WithMinerAddressGetter(ag func() address.Address) HeartbeatServiceOption {
        return func(service *HeartbeatService) {
            service.MinerAddressGetter = ag
        }
    }
    
    • 获取默认的矿工地址
    func defaultMinerAddressGetter() address.Address {
        return address.Address{}
    }
    
    • 实例化心跳服务,具体的实例化在node包中实现。
    // NewHeartbeatService returns a HeartbeatService
    func NewHeartbeatService(h host.Host, hbc *config.HeartbeatConfig, hg func() types.TipSet, options ...HeartbeatServiceOption) *HeartbeatService {
        srv := &HeartbeatService{
            Host:               h,
            Config:             hbc,
            HeadGetter:         hg,
            MinerAddressGetter: defaultMinerAddressGetter,
        }
    
        // 设置心跳服务的获取矿工属性,这会覆盖到上面设置的默认矿工地址
        for _, option := range options {
            option(srv)
        }
    
        return srv
    }
    

    5.2.4 实例化及业务逻辑

    • 主要由node调用,location:node/node.go,主要逻辑如下

    • 在node的启动方法中,调用node.setupHeartbeatServices方法,建立心跳服务

    // Start boots up the node.
    func (node *Node) Start(ctx context.Context) error {
        ......
    
        if err := node.setupHeartbeatServices(ctx); err != nil {
            return errors.Wrap(err, "failed to start heartbeat services")
        }
    
        return nil
    }
    
    • 建立心跳服务,具体见如下注释
    func (node *Node) setupHeartbeatServices(ctx context.Context) error {
        // 设置“矿工地址获取函数”
        mag := func() address.Address {
            addr, err := node.miningAddress()
            // the only error miningAddress() returns is ErrNoMinerAddress.
            // if there is no configured miner address, simply send a zero
            // address across the wire.
            if err != nil {
                return address.Address{}
            }
            return addr
        }
    
        // 存在心跳目标的时候,实例化心跳服务实例
        // start the primary heartbeat service
        if len(node.Repo.Config().Heartbeat.BeatTarget) > 0 {
            //调用metrics包中的建立心跳服务实例、以及启动心跳服务实例方法
            hbs := metrics.NewHeartbeatService(node.Host(), node.Repo.Config().Heartbeat, node.ChainReader.Head, metrics.WithMinerAddressGetter(mag))
            go hbs.Start(ctx)
        }
    
        // 确认是否用户有通过环境变量配置额外的心跳告警服务(自定义指向其他节点),根据用户配置的数目,拉起对应的多线程心跳服务。
        // check if we want to connect to an alert service. An alerting service is a heartbeat
        // service that can trigger alerts based on the contents of heatbeats.
        if alertTarget := os.Getenv("FIL_HEARTBEAT_ALERTS"); len(alertTarget) > 0 {
            ahbs := metrics.NewHeartbeatService(node.Host(), &config.HeartbeatConfig{
                BeatTarget:      alertTarget,
                BeatPeriod:      "10s",
                ReconnectPeriod: "10s",
                Nickname:        node.Repo.Config().Heartbeat.Nickname,
            }, node.ChainReader.Head, metrics.WithMinerAddressGetter(mag))
            go ahbs.Start(ctx)
        }
        return nil
    }
    

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