Return non-zero exit code in case of errors

At the moment, k8s and k8sd return 0 even if the command fails,
which is a problem especially when used inside scripts.

We'll ensure that a non-zero exit code is returned if the commands
fail.

src/k8s/cmd/main.go

@@ -30,14 +30,20 @@ func main() {
 
 	// choose command based on the binary name
 	base := filepath.Base(os.Args[0])
+	var err error
 	switch base {
 	case "k8s-apiserver-proxy":
-		k8s_apiserver_proxy.NewRootCmd(env).ExecuteContext(ctx)
+		err = k8s_apiserver_proxy.NewRootCmd(env).ExecuteContext(ctx)
 	case "k8sd":
-		k8sd.NewRootCmd(env).ExecuteContext(ctx)
+		err = k8sd.NewRootCmd(env).ExecuteContext(ctx)
 	case "k8s":
-		k8s.NewRootCmd(env).ExecuteContext(ctx)
+		err = k8s.NewRootCmd(env).ExecuteContext(ctx)
 	default:
 		panic(fmt.Errorf("invalid entrypoint name %q", base))
 	}
+
+	// Return a non-zero exit code if the command failed.
+	if err != nil {
+		os.Exit(1);
+	}
 }