main.go

package main

import (
	"flag"
	"fmt"
	"os"
	"syscall"
	"time"

	"github.com/fsnotify/fsnotify"
	log "github.com/sirupsen/logrus"
	pluginapi "k8s.io/kubelet/pkg/apis/deviceplugin/v1beta1"
)

func main() {
	// Parse command-line arguments
	flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
	flagLogLevel := flag.String("log-level", "info", "Define the logging level: error, info, debug.")
	flag.Parse()

	if flag.NArg() != 1 {
		fmt.Println("Must specify config file")
		return
	}

	switch *flagLogLevel {
	case "debug":
		log.SetLevel(log.DebugLevel)
	case "info":
		log.SetLevel(log.InfoLevel)
	}

	log.Println("Fetching devices.")

	resource, err := readconfig(flag.Arg(0))
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}

	if len(resource.Sets) == 0 {
		log.Println("No resource set found.")
		os.Exit(1)
	}

	log.Debugf("Generic device config: %v", resource)
	log.Println("Starting FS watcher.")

	watcher, err := newFSWatcher(pluginapi.DevicePluginPath)
	if err != nil {
		log.Println("Failed to created FS watcher.")
		os.Exit(1)
	}
	defer watcher.Close()

	log.Println("Starting OS watcher.")
	sigs := newOSWatcher(syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)

	restart := true
	var devicePlugin *genericDevicePlugin

L:
	for {
		if restart {
			if devicePlugin != nil {
				devicePlugin.Stop()
				time.Sleep(1 * time.Second)
			}

			devicePlugin = newGenericDevicePlugin(resource)
			if err := devicePlugin.Serve(); err != nil {
				log.Println("Could not contact Kubelet, retrying. Did you enable the device plugin feature gate?")
			} else {
				restart = false
			}
		}

		select {
		case event := <-watcher.Events:
			if event.Name == pluginapi.KubeletSocket && event.Op&fsnotify.Create == fsnotify.Create {
				log.Printf("inotify: %s created, restarting.", pluginapi.KubeletSocket)
				restart = true
			}

		case err := <-watcher.Errors:
			log.Printf("inotify: %s", err)

		case s := <-sigs:
			switch s {
			case syscall.SIGHUP:
				log.Println("Received SIGHUP, restarting.")
				restart = true
			default:
				log.Printf("Received signal \"%v\", shutting down.", s)
				devicePlugin.Stop()
				break L
			}
		}
	}
}