Support kubectl symlink and avoid data in home dir

cmd/k3s/main.go

@@ -18,11 +18,15 @@ import (
 )
 
 func main() {
+	if runKubectl() {
+		return
+	}
+
 	app := cmds.NewApp()
 	app.Commands = []cli.Command{
 		cmds.NewServerCommand(wrap("k3s-server", os.Args)),
 		cmds.NewAgentCommand(wrap("k3s-agent", os.Args)),
-		cmds.NewKubectlCommand(kubectl),
+		cmds.NewKubectlCommand(kubectlCLI),
 	}
 
 	err := app.Run(os.Args)
@@ -31,25 +35,46 @@ func main() {
 	}
 }
 
-func kubectl(ctx *cli.Context) error {
-	return stageAndRun(ctx, "kubectl", append([]string{"kubectl"}, ctx.Args()...))
+func runKubectl() bool {
+	if filepath.Base(os.Args[0]) == "kubectl" {
+		if err := kubectl("", os.Args[1:]); err != nil {
+			logrus.Fatal(err)
+		}
+		return true
+	}
+	return false
+}
+
+func kubectlCLI(cli *cli.Context) error {
+	return kubectl(cli.String("data-dir"), cli.Args())
+}
+
+func kubectl(dataDir string, args []string) error {
+	dataDir, err := datadir.Resolve(dataDir)
+	if err != nil {
+		return err
+	}
+	return stageAndRun(dataDir, "kubectl", append([]string{"kubectl"}, args...))
 }
 
 func wrap(cmd string, args []string) func(ctx *cli.Context) error {
 	return func(ctx *cli.Context) error {
-		return stageAndRun(ctx, cmd, args)
+		return stageAndRunCLI(ctx, cmd, args)
 	}
 }
 
-func stageAndRun(cli *cli.Context, cmd string, args []string) error {
+func stageAndRunCLI(cli *cli.Context, cmd string, args []string) error {
 	dataDir, err := datadir.Resolve(cli.String("data-dir"))
 	if err != nil {
 		return err
 	}
 
-	asset, dir := getAssetAndDir(dataDir)
+	return stageAndRun(dataDir, cmd, args)
+}
 
-	if err := extract(asset, dir); err != nil {
+func stageAndRun(dataDir string, cmd string, args []string) error {
+	dir, err := extract(dataDir)
+	if err != nil {
 		return errors.Wrap(err, "extracting data")
 	}
 
@@ -62,6 +87,7 @@ func stageAndRun(cli *cli.Context, cmd string, args []string) error {
 		return err
 	}
 
+	logrus.Debugf("Running %s %v", cmd, args)
 	return syscall.Exec(cmd, args, os.Environ())
 }
 
@@ -71,18 +97,25 @@ func getAssetAndDir(dataDir string) (string, string) {
 	return asset, dir
 }
 
-func extract(asset, dir string) error {
-	logrus.Debugf("Asset dir %s", dir)
+func extract(dataDir string) (string, error) {
+	// first look for global asset folder so we don't create a HOME version if not needed
+	asset, dir := getAssetAndDir(datadir.DefaultDataDir)
+	if _, err := os.Stat(dir); err == nil {
+		logrus.Debugf("Asset dir %s", dir)
+		return dir, nil
+	}
 
+	asset, dir = getAssetAndDir(dataDir)
 	if _, err := os.Stat(dir); err == nil {
-		return nil
+		logrus.Debugf("Asset dir %s", dir)
+		return "", nil
 	}
 
 	logrus.Infof("Preparing data dir %s", dir)
 
 	content, err := data.Asset(asset)
 	if err != nil {
-		return err
+		return "", err
 	}
 	buf := bytes.NewBuffer(content)
 
@@ -92,8 +125,8 @@ func extract(asset, dir string) error {
 	os.RemoveAll(tempDest)
 
 	if err := untar.Untar(buf, tempDest); err != nil {
-		return err
+		return "", err
 	}
 
-	return os.Rename(tempDest, dir)
+	return dir, os.Rename(tempDest, dir)
 }

pkg/datadir/datadir.go

@@ -7,12 +7,17 @@ import (
 	"github.com/rancher/norman/pkg/resolvehome"
 )
 
+const (
+	DefaultDataDir     = "/var/lib/rancher/k3s"
+	DefaultHomeDataDir = "${HOME}/.rancher/k3s"
+)
+
 func Resolve(dataDir string) (string, error) {
 	if dataDir == "" {
 		if os.Getuid() == 0 {
-			dataDir = "/var/lib/rancher/k3s"
+			dataDir = DefaultDataDir
 		} else {
-			dataDir = "${HOME}/.rancher/k3s"
+			dataDir = DefaultHomeDataDir
 		}
 	}