cli: better error handling for subcommand args

Some subcommands need following arguments (e.g.: ogcli list ...), check
if following arguments are present. If no required following argument is
detected then print an error message, show help and exit with status
code 1.

cli/cli.py

@@ -73,8 +73,13 @@ class OgCLI():
                    'servers']
         parser = argparse.ArgumentParser(prog='ogcli list')
         parser.add_argument('item', choices=choices)
-        parsed_args = parser.parse_args([args[0]])
 
+        if not args:
+            print('Missing list subcommand', file=sys.stderr)
+            parser.print_help(file=sys.stderr)
+            sys.exit(1)
+
+        parsed_args = parser.parse_args([args[0]])
         if parsed_args.item == 'clients':
             OgClient.list_clients(self.rest)
         elif parsed_args.item == 'client':
@@ -96,8 +101,13 @@ class OgCLI():
         choices = ['modes', 'mode', 'server']
         parser = argparse.ArgumentParser(prog='ogcli set')
         parser.add_argument('item', choices=choices)
-        parsed_args = parser.parse_args([args[0]])
 
+        if not args:
+            print('Missing set subcommand', file=sys.stderr)
+            parser.print_help(file=sys.stderr)
+            sys.exit(1)
+
+        parsed_args = parser.parse_args([args[0]])
         if parsed_args.item in ['modes', 'mode']:
             OgModes.set_modes(self.rest, args[1:])
         elif parsed_args.item == 'server':
@@ -107,8 +117,13 @@ class OgCLI():
         choices = ['reboot', 'refresh', 'poweroff', 'wol']
         parser = argparse.ArgumentParser(prog='ogcli send')
         parser.add_argument('send_obj', choices=choices)
-        parsed_args = parser.parse_args([args[0]])
 
+        if not args:
+            print('Missing send subcommand', file=sys.stderr)
+            parser.print_help(file=sys.stderr)
+            sys.exit(1)
+
+        parsed_args = parser.parse_args([args[0]])
         if parsed_args.send_obj == 'wol':
             OgWol.send_wol(self.rest, args[1:])
         elif parsed_args.send_obj == 'poweroff':
@@ -122,8 +137,13 @@ class OgCLI():
         choices = ['image']
         parser = argparse.ArgumentParser(prog='ogcli restore')
         parser.add_argument('send_obj', choices=choices)
-        parsed_args = parser.parse_args([args[0]])
 
+        if not args:
+            print('Missing restore subcommand', file=sys.stderr)
+            parser.print_help(file=sys.stderr)
+            sys.exit(1)
+
+        parsed_args = parser.parse_args([args[0]])
         if parsed_args.send_obj == 'image':
             OgImage.restore_image(self.rest, args[1:])
 
@@ -131,8 +151,13 @@ class OgCLI():
         choices = ['image']
         parser = argparse.ArgumentParser(prog='ogcli create')
         parser.add_argument('create_obj', choices=choices)
-        parsed_args = parser.parse_args([args[0]])
 
+        if not args:
+            print('Missing create subcommand', file=sys.stderr)
+            parser.print_help(file=sys.stderr)
+            sys.exit(1)
+
+        parsed_args = parser.parse_args([args[0]])
         if parsed_args.create_obj == 'image':
             OgImage.create_image(self.rest, args[1:])
 
@@ -140,8 +165,13 @@ class OgCLI():
         choices = ['disk']
         parser = argparse.ArgumentParser(prog='ogcli setup')
         parser.add_argument('setup_obj', choices=choices)
-        parsed_args = parser.parse_args([args[0]])
 
+        if not args:
+            print('Missing setup subcommand', file=sys.stderr)
+            parser.print_help(file=sys.stderr)
+            sys.exit(1)
+
+        parsed_args = parser.parse_args([args[0]])
         if parsed_args.setup_obj == 'disk':
             OgDisk.setup_disk(self.rest, args[1:])
 
@@ -149,8 +179,13 @@ class OgCLI():
         choices = ['image']
         parser = argparse.ArgumentParser(prog='ogcli update')
         parser.add_argument('update_obj', choices=choices)
-        parsed_args = parser.parse_args([args[0]])
 
+        if not args:
+            print('Missing update subcommand', file=sys.stderr)
+            parser.print_help(file=sys.stderr)
+            sys.exit(1)
+
+        parsed_args = parser.parse_args([args[0]])
         if parsed_args.update_obj == 'image':
             OgImage.update_image(self.rest, args[1:])
 
@@ -158,8 +193,13 @@ class OgCLI():
         choices = ['server']
         parser = argparse.ArgumentParser(prog='ogcli delete')
         parser.add_argument('delete_obj', choices=choices)
-        parsed_args = parser.parse_args([args[0]])
 
+        if not args:
+            print('Missing delete subcommand', file=sys.stderr)
+            parser.print_help(file=sys.stderr)
+            sys.exit(1)
+
+        parsed_args = parser.parse_args([args[0]])
         if parsed_args.delete_obj == 'server':
             OgServer.delete_server(self.rest, args[1:])
 
@@ -167,7 +207,12 @@ class OgCLI():
         choices = ['server']
         parser = argparse.ArgumentParser(prog='ogcli add')
         parser.add_argument('add_obj', choices=choices)
-        parsed_args = parser.parse_args([args[0]])
 
+        if not args:
+            print('Missing add subcommand', file=sys.stderr)
+            parser.print_help(file=sys.stderr)
+            sys.exit(1)
+
+        parsed_args = parser.parse_args([args[0]])
         if parsed_args.add_obj == 'server':
             OgServer.add_server(self.rest, args[1:])