NSQ 源码分析之NSQD 的启动
1.NSQD的配置(nsqd/options.go)包括如下参数：
type Options struct {
/*******************基本信息配置*********************/
//节点ID
ID int64 `flag:"node-id" cfg:"id"`
//日志等级(可参考nsqd/logger.go)
LogLevel lg.LogLevel `flag:"log-level"`
//日志前缀
LogPrefix string `flag:"log-prefix"`
Logger Logger
/*******************地址配置，包括tcp,http,https等*********************/
//....
/*******************持久化配置*********************/
//元数据存储地址（topic/channel的信息）
DataPath string `flag:"data-path"`
//每个channel最大消息个数，如果超过就需要写入磁盘
MemQueueSize int64 `flag:"mem-queue-size"`
//写入磁盘的文件名格式是 xx-000000001, 该配置表示文件名的最大bit位
//如果是2，文件格式是 xx-00
MaxBytesPerFile int64 `flag:"max-bytes-per-file"`
//缓冲区内容同步到磁盘的时间间隔
SyncEvery int64 `flag:"sync-every"`
//同步超时时间
SyncTimeout time.Duration `flag:"sync-timeout"`
/*******************nsqd.queueScanLoop 函数中使用如下参数*********************/
//nsqd 扫描延时队列或者未ack队列的时间间隔
QueueScanInterval time.Duration
//nsqd 调整工作线程和刷新topic.channel的时间间隔
QueueScanRefreshInterval time.Duration
//nsqd 扫描channel的数量
QueueScanSelectionCount int `flag:"queue-scan-selection-count"`
//nsqd 扫描各种队列的最大工作线程
QueueScanWorkerPoolMax int `flag:"queue-scan-worker-pool-max"`
//nsqd 允许扫描失败的比例。
QueueScanDirtyPercent float64
/*******************MQ消息和命令相关配置*********************/
//消息最大为被ack的时间，超过这个时间会被重新推入队列，重新消费
MsgTimeout time.Duration `flag:"msg-timeout"`
MaxMsgTimeout time.Duration `flag:"max-msg-timeout"`
//单个消息的最大字节数
MaxMsgSize int64 `flag:"max-msg-size"`
//批量消息的，最大字节数
MaxBodySize int64 `flag:"max-body-size"`
MaxReqTimeout time.Duration `flag:"max-req-timeout"`
ClientTimeout time.Duration
/*******************客户端相关配置*********************/
//心跳间隔时间
MaxHeartbeatInterval time.Duration `flag:"max-heartbeat-interval"`
//????
MaxRdyCount int64 `flag:"max-rdy-count"`
MaxOutputBufferSize int64 `flag:"max-output-buffer-size"`
//根据最大最小缓存输出时间，生成一个desiredTimeout
MaxOutputBufferTimeout time.Duration `flag:"max-output-buffer-timeout"`
MinOutputBufferTimeout time.Duration `flag:"min-output-buffer-timeout"`
OutputBufferTimeout time.Duration `flag:"output-buffer-timeout"`
//channel的最多消费者数量
MaxChannelConsumers int `flag:"max-channel-consumers"`
// statsd integration
StatsdAddress string `flag:"statsd-address"`
StatsdPrefix string `flag:"statsd-prefix"`
StatsdInterval time.Duration `flag:"statsd-interval"`
StatsdMemStats bool `flag:"statsd-mem-stats"`
StatsdUDPPacketSize int `flag:"statsd-udp-packet-size"`
// e2e message latency
E2EProcessingLatencyWindowTime time.Duration `flag:"e2e-processing-latency-window-time"`
E2EProcessingLatencyPercentiles []float64 `flag:"e2e-processing-latency-percentile" cfg:"e2e_processing_latency_percentiles"`
// TLS config
TLSCert string `flag:"tls-cert"`
TLSKey string `flag:"tls-key"`
TLSClientAuthPolicy string `flag:"tls-client-auth-policy"`
TLSRootCAFile string `flag:"tls-root-ca-file"`
TLSRequired int `flag:"tls-required"`
TLSMinVersion uint16 `flag:"tls-min-version"`
// compression
DeflateEnabled bool `flag:"deflate"`
MaxDeflateLevel int `flag:"max-deflate-level"`
SnappyEnabled bool `flag:"snappy"`
}2.nsqd.New 实例化流程
func New(opts *Options) (*NSQD, error) {
var err error
//元数据存储地址，元数据包括 topic 和 channel,具体可参考 meta 结构体
dataPath := opts.DataPath
if opts.DataPath == "" {
cwd, _ := os.Getwd()
dataPath = cwd
}
//日志
if opts.Logger == nil {
opts.Logger = log.New(os.Stderr, opts.LogPrefix, log.Ldate|log.Ltime|log.Lmicroseconds)
}
n := &NSQD{
startTime: time.Now(),
topicMap: make(map[string]*Topic),
clients: make(map[int64]Client),
exitChan: make(chan int),
notifyChan: make(chan interface{}),
optsNotificationChan: make(chan struct{}, 1),
dl: dirlock.New(dataPath),
}
//http 客户端，专门用于访问lookupd，上报或获取client,topic,channel的信息
httpcli := http_api.NewClient(nil, opts.HTTPClientConnectTimeout, opts.HTTPClientRequestTimeout)
n.ci = clusterinfo.New(n.logf, httpcli)
//lookupd 集群 设置为空，后面会通过lookup 线程补充
n.lookupPeers.Store([]*lookupPeer{})
//存储配置
n.swapOpts(opts)
n.errValue.Store(errStore{})
//.... 省略中间过程
//TCP 连接处理（tcp.go）
n.tcpServer = &tcpServer{}
//监听
n.tcpListener, err = net.Listen("tcp", opts.TCPAddress)
if err != nil {
return nil, fmt.Errorf("listen (%s) failed - %s", opts.TCPAddress, err)
}
//httP 服务监听
n.httpListener, err = net.Listen("tcp", opts.HTTPAddress)
if err != nil {
return nil, fmt.Errorf("listen (%s) failed - %s", opts.HTTPAddress, err)
}
if n.tlsConfig != nil && opts.HTTPSAddress != "" {
//https 监听
n.httpsListener, err = tls.Listen("tcp", opts.HTTPSAddress, n.tlsConfig)
if err != nil {
return nil, fmt.Errorf("listen (%s) failed - %s", opts.HTTPSAddress, err)
}
}
return n, nil
}3.nsqd.Main 启动过程
func (n *NSQD) Main() error {
ctx := &context{n}
exitCh := make(chan error)
var once sync.Once
exitFunc := func(err error) {
once.Do(func() {
if err != nil {
n.logf(LOG_FATAL, "%s", err)
}
exitCh <- err
})
}
n.tcpServer.ctx = ctx
/*
util.WaitGroupWrapper(internal/util/wait_group_wrapper.go)
这个方法只是，包装了 Add,和Done的操作
*/
//启动TCP 服务监听(tcp.go Handle)
n.waitGroup.Wrap(func() {
exitFunc(protocol.TCPServer(n.tcpListener, n.tcpServer, n.logf))
})
httpServer := newHTTPServer(ctx, false, n.getOpts().TLSRequired == TLSRequired)
//启动Http 服务监听 (http.go)
n.waitGroup.Wrap(func() {
exitFunc(http_api.Serve(n.httpListener, httpServer, "HTTP", n.logf))
})
if n.tlsConfig != nil && n.getOpts().HTTPSAddress != "" {
httpsServer := newHTTPServer(ctx, true, true)
n.waitGroup.Wrap(func() {
exitFunc(http_api.Serve(n.httpsListener, httpsServer, "HTTPS", n.logf))
})
}
//启动延迟队列和超时队列等处理线程
n.waitGroup.Wrap(n.queueScanLoop)
//启动集群上报 client,topic,channel等处理线程
n.waitGroup.Wrap(n.lookupLoop)
if n.getOpts().StatsdAddress != "" {
n.waitGroup.Wrap(n.statsdLoop)
}
err := <-exitCh
return err
}总结
nsqd的启动包括：
1.配置NSQD参数(option.go)
2.实例化nsqd(New)
3.启动tcp服务监听、http/https监听、queueScanLoop线程及lookupLoop线程
下次分享：nsqd中tcp 服务监听部分。