burke/zeus

package zeusmaster

import (
    "fmt"
    "net"
    "os"
    "os/signal"
    "strconv"
    "syscall"
    "time"

    "github.com/burke/zeus/go/clienthandler"
    "github.com/burke/zeus/go/config"
    "github.com/burke/zeus/go/filemonitor"
    "github.com/burke/zeus/go/processtree"
    slog "github.com/burke/zeus/go/shinylog"
    "github.com/burke/zeus/go/statuschart"
    "github.com/burke/zeus/go/zerror"
    "github.com/burke/zeus/go/zeusversion"
)

const listenerPortVar = "ZEUS_NETWORK_FILE_MONITOR_PORT"

// man signal | grep 'terminate process' | awk '{print $2}' | xargs -I '{}' echo -n "syscall.{}, "
// Leaving out SIGPIPE as that is a signal the master receives if a client process is killed.
var terminatingSignals = []os.Signal{syscall.SIGHUP, syscall.SIGINT, syscall.SIGKILL, syscall.SIGALRM, syscall.SIGTERM, syscall.SIGXCPU, syscall.SIGXFSZ, syscall.SIGVTALRM, syscall.SIGPROF, syscall.SIGUSR1, syscall.SIGUSR2}

func Run(configFile string, fileChangeDelay time.Duration, simpleStatus bool) int {
    slog.Colorized("{green}Starting {yellow}Z{red}e{blue}u{magenta}s{green} server v" + zeusversion.VERSION)

    zerror.Init()

    monitor, err := buildFileMonitor(fileChangeDelay)
    if err != nil {
        return 2
    }

    var tree = config.BuildProcessTree(configFile, monitor)

    done := make(chan bool)

    defer exit(processtree.StartSlaveMonitor(tree, monitor.Listen(), done), done)
    defer exit(clienthandler.Start(tree, done), done)
    defer monitor.Close()
    defer slog.Suppress()
    defer zerror.PrintFinalOutput()
    defer exit(statuschart.Start(tree, done, simpleStatus), done)

    c := make(chan os.Signal, 1)
    signal.Notify(c, terminatingSignals...)

    for {
        select {
        case sig := <-c:
            if sig == syscall.SIGINT {
                return 0
            }
            return 1
        }
    }
}

func exit(quit, done chan bool) {
    // Signal the process to quit.
    close(quit)
    // Wait until the process signals it's done.
    <-done
}

func buildFileMonitor(fileChangeDelay time.Duration) (filemonitor.FileMonitor, error) {
    if portStr := os.Getenv(listenerPortVar); portStr != "" {
        port, err := strconv.Atoi(portStr)
        if err != nil {
            return nil, fmt.Errorf("%s must be an integer or empty string: %v", listenerPortVar, err)
        }

        ln, err := net.ListenTCP("tcp", &net.TCPAddr{
            IP:   net.ParseIP("127.0.0.1"),
            Port: port,
        })
        if err != nil {
            return nil, err
        }

        return filemonitor.NewFileListener(fileChangeDelay, ln), nil
    }

    monitor, err := filemonitor.NewFileMonitor(fileChangeDelay)
    if err != nil {
        return nil, err
    }

    return monitor, nil
}