make nebula a service that can install itself

cmd/nebula-service/main.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+
+	"github.com/slackhq/nebula"
+)
+
+// A version string that can be set with
+//
+//     -ldflags "-X main.Build=SOMEVERSION"
+//
+// at compile-time.
+var Build string
+
+func main() {
+	serviceFlag := flag.String("service", "", "Control the system service.")
+	configPath := flag.String("config", "", "Path to either a file or directory to load configuration from")
+	configTest := flag.Bool("test", false, "Test the config and print the end result. Non zero exit indicates a faulty config")
+	printVersion := flag.Bool("version", false, "Print version")
+	printUsage := flag.Bool("help", false, "Print command line usage")
+
+	flag.Parse()
+
+	if *printVersion {
+		fmt.Printf("Build: %s\n", Build)
+		os.Exit(0)
+	}
+
+	if *printUsage {
+		flag.Usage()
+		os.Exit(0)
+	}
+
+	if *serviceFlag != "" {
+		doService(configPath, configTest, Build, serviceFlag)
+		os.Exit(1)
+	}
+
+	if *configPath == "" {
+		fmt.Println("-config flag must be set")
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	nebula.Main(*configPath, *configTest, Build)
+}

cmd/nebula-service/service.go

@@ -0,0 +1,106 @@
+package main
+
+import (
+	"log"
+	"os"
+	"path/filepath"
+
+	"github.com/kardianos/service"
+	"github.com/slackhq/nebula"
+)
+
+var logger service.Logger
+
+type program struct {
+	exit       chan struct{}
+	configPath *string
+	configTest *bool
+	build      string
+}
+
+func (p *program) Start(s service.Service) error {
+	if service.Interactive() {
+		logger.Info("Running in terminal.")
+	} else {
+		logger.Info("Running under service manager.")
+	}
+	p.exit = make(chan struct{})
+
+	// Start should not block. Do the actual work async.
+	go p.run()
+	return nil
+}
+
+func (p *program) run() error {
+	nebula.Main(*p.configPath, *p.configTest, Build)
+	return nil
+}
+
+func (p *program) Stop(s service.Service) error {
+	// Any work in Stop should be quick, usually a few seconds at most.
+	logger.Info("I'm Stopping!")
+	close(p.exit)
+	return nil
+}
+
+func doService(configPath *string, configTest *bool, build string, serviceFlag *string) {
+
+	if *configPath == "" {
+		ex, err := os.Executable()
+		if err != nil {
+			panic(err)
+		}
+		*configPath = filepath.Dir(ex) + "/config.yaml"
+	}
+
+	svcConfig := &service.Config{
+		Name:        "Nebula",
+		DisplayName: "Nebula Network Service",
+		Description: "Nebula network connectivity daemon for encrypted communications",
+		Arguments:   []string{"-service", "run", "-config", *configPath},
+	}
+
+	prg := &program{
+		configPath: configPath,
+		configTest: configTest,
+		build:      build,
+	}
+
+	s, err := service.New(prg, svcConfig)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	errs := make(chan error, 5)
+	logger, err = s.Logger(errs)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	go func() {
+		for {
+			err := <-errs
+			if err != nil {
+				log.Print(err)
+			}
+		}
+	}()
+
+	//if len(*serviceFlag) != 0 {
+	switch *serviceFlag {
+	case "run":
+		err = s.Run()
+		if err != nil {
+			logger.Error(err)
+		}
+	default:
+		err := service.Control(s, *serviceFlag)
+		if err != nil {
+			log.Printf("Valid actions: %q\n", service.ControlAction)
+			log.Fatal(err)
+		}
+		return
+		//}
+	}
+
+}