crc-embedder: Use cobra.ExactArgs

Checks for the number of arguments was done manually (`len(args)`)
while cobra provides a helper for this.
This also adds a missing check in `crc-embedder download`

cmd/crc-embedder/cmd/download.go

@@ -11,6 +11,7 @@ func init() {
 }
 
 var downloadCmd = &cobra.Command{
+	Args:  cobra.ExactArgs(1),
 	Use:   "download",
 	Short: "Download data files embedded in the crc executable",
 	RunE: func(cmd *cobra.Command, args []string) error {

cmd/crc-embedder/cmd/embed.go

@@ -30,6 +30,7 @@ func init() {
 }
 
 var embedCmd = &cobra.Command{
+	Args:  cobra.ExactArgs(1),
 	Use:   "embed",
 	Short: "Embed data files in crc executable",
 	Long:  `Embed the OpenShift bundle and the binaries needed at runtime in the crc executable`,
@@ -39,9 +40,6 @@ var embedCmd = &cobra.Command{
 }
 
 func runEmbed(args []string) {
-	if len(args) != 1 {
-		logging.Fatal("embed takes exactly one argument")
-	}
 	executablePath := args[0]
 	destDir, err := ioutil.TempDir("", "crc-embedder")
 	if err != nil {

cmd/crc-embedder/cmd/extract.go

@@ -13,6 +13,7 @@ func init() {
 }
 
 var extractCmd = &cobra.Command{
+	Args:  cobra.ExactArgs(3),
 	Use:   "extract",
 	Short: "Extract data file embedded in the crc executable",
 	Long:  `Extract a data file which is embedded in the crc executable`,
@@ -22,9 +23,6 @@ var extractCmd = &cobra.Command{
 }
 
 func runExtract(args []string) {
-	if len(args) != 3 {
-		logging.Fatalf("extract takes exactly three arguments")
-	}
 	executablePath := args[0]
 	embedName := args[1]
 	destFile := args[2]

cmd/crc-embedder/cmd/list.go

@@ -13,6 +13,7 @@ func init() {
 }
 
 var listCmd = &cobra.Command{
+	Args:  cobra.ExactArgs(1),
 	Use:   "list",
 	Short: "List data files embedded in the crc executable",
 	Long:  `List all the data files which were embedded in the crc executable`,
@@ -22,9 +23,6 @@ var listCmd = &cobra.Command{
 }
 
 func runList(args []string) {
-	if len(args) != 1 {
-		logging.Fatalf("list takes exactly one argument")
-	}
 	executablePath := args[0]
 	extractor, err := binappend.MakeExtractor(executablePath)
 	if err != nil {