go语言版本：1.8.3 linux/amd64

InfluxDB版本：1.1.0

源码路径： github.com/influxdata/influxdb/cmd/influxd

程序入口（main.go）：

func main() {
    rand.Seed(time.Now().UnixNano())

    m := NewMain()
    if err := m.Run(os.Args[1:]...); err != nil {
        fmt.Fprintln(os.Stderr, err)
        os.Exit(1)
    }
}

在main函数中，调用Main.Run函数。

如命令行参数为空或"run"，则执行如下流程：

case "", "run":
    cmd := run.NewCommand()

    // Tell the server the build details.
    cmd.Version = version
    cmd.Commit = commit
    cmd.Branch = branch

    if err := cmd.Run(args...); err != nil {
        return fmt.Errorf("run: %s", err)
    }

    signalCh := make(chan os.Signal, 1)
    signal.Notify(signalCh, os.Interrupt, syscall.SIGTERM)
    m.Logger.Println("Listening for signals")

    // Block until one of the signals above is received
    select {
    case <-signalCh:
        m.Logger.Println("Signal received, initializing clean shutdown...")
        go func() {
            cmd.Close()
        }()
    }

    // Block again until another signal is received, a shutdown timeout elapses,
    // or the Command is gracefully closed
    m.Logger.Println("Waiting for clean shutdown...")
    select {
    case <-signalCh:
        m.Logger.Println("second signal received, initializing hard shutdown")
    case <-time.After(time.Second * 30):
        m.Logger.Println("time limit reached, initializing hard shutdown")
    case <-cmd.Closed:
        m.Logger.Println("server shutdown completed")
    }

    // goodbye.

执行 Command.Run 函数，后面跟的代码是处理系统信号的相关内容。

Command.Run函数内容如下：

func (cmd *Command) Run(args ...string) error {
    // Parse the command line flags.
    options, err := cmd.ParseFlags(args...)
    if err != nil {
        return err
    }

    // Print sweet InfluxDB logo.
    fmt.Print(logo)

    // Configure default logging.
    log.SetPrefix("[run] ")
    log.SetFlags(log.LstdFlags)

    // Set parallelism.
    runtime.GOMAXPROCS(runtime.NumCPU())

    // Mark start-up in log.
    log.Printf("InfluxDB starting, version %s, branch %s, commit %s",
        cmd.Version, cmd.Branch, cmd.Commit)
    log.Printf("Go version %s, GOMAXPROCS set to %d", runtime.Version(), runtime.GOMAXPROCS(0))

    // Write the PID file.
    if err := cmd.writePIDFile(options.PIDFile); err != nil {
        return fmt.Errorf("write pid file: %s", err)
    }

    // Parse config
    config, err := cmd.ParseConfig(options.GetConfigPath())
    if err != nil {
        return fmt.Errorf("parse config: %s", err)
    }