carve out cmd, stub server impl

cmd/kubelwagen/root.go

@@ -1,6 +1,10 @@
 package main
 
-import "github.com/spf13/cobra"
+import (
+	"os"
+
+	"github.com/spf13/cobra"
+)
 
 var rootCmd = &cobra.Command{
 	Use:   "kubelwagen",
@@ -9,4 +13,7 @@ var rootCmd = &cobra.Command{
 	Run:   rootRun,
 }
 
-func rootRun(cmd *cobra.Command)
+func rootRun(cmd *cobra.Command, args []string) {
+	cmd.Usage()
+	os.Exit(1)
+}

cmd/kubelwagen/serve.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+var (
+	hostport string
+)
+
+func init() {
+	rootCmd.AddCommand(serveCmd)
+	serveCmd.PersistentFlags().StringVar(&hostport, "listen", "0.0.0.0:8889", "Host and port to listen on")
+}
+
+var serveCmd = &cobra.Command{
+	Use:   "serve DIR",
+	Short: "Create a FUSE mount at DIR",
+	Run:   serveRun,
+}
+
+func serveRun(cmd *cobra.Command, args []string) {
+	if len(args) != 1 {
+		cmd.Usage()
+		os.Exit(1)
+	}
+	dir := args[0]
+	kubelwagen.Serve(hostport, dir)
+}