Add option to remove group from inventory

Added `-d` option to inventory-manage.py that will remove provided
group from the inventory. It won't touch conf.d so you need to remove
entry from there before re-running dynamic_inventory

Depends-On: https://review.opendev.org/c/openstack/openstack-ansible-galera_server/+/791107
Change-Id: I665ae5ce999c36d8d999ed5f9d659095a900d9eb
Closes-Bug: #1642051

doc/source/reference/inventory/manage-inventory.rst

@@ -43,6 +43,15 @@ Use the host's name as an argument.
 
 ..  _`dynamic inventory functionality`: https://docs.ansible.com/ansible/intro_dynamic_inventory.html
 
+Removing a group
+~~~~~~~~~~~~~~~~
+
+A host group can be removed with the ``--remove-group/-d`` parameter.
+
+Use the groups's name as an argument. You can repeat argument multiple times
+to remove several groups at once.
+
+
 Exporting host information
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 

osa_toolkit/manage.py

@@ -58,6 +58,14 @@ def args():
         action='append',
         default=[]
     )
+    exclusive_action.add_argument(
+        '-d',
+        '--remove-group',
+        help='group name to remove from inventory, this can be used multiple'
+             ' times.',
+        action='append',
+        default=[]
+    )
     exclusive_action.add_argument(
         '-l',
         '--list-host',
@@ -310,6 +318,16 @@ def remove_ip_addresses(inventory, filepath=None):
         filesys.save_inventory(inventory_json, filepath)
 
 
+def remove_inventory_group(remove_group, inventory, filepath=None):
+    for group in remove_group:
+        inventory.pop(group, None)
+
+    if filepath is not None:
+        inventory_json = json.dumps(inventory, indent=2,
+                                    separators=(',', ': '))
+        filesys.save_inventory(inventory_json, filepath)
+
+
 def remove_inventory_item(remove_item, inventory, filepath=None):
     """Removes inventory item from the inventory dictionary
 
@@ -350,6 +368,9 @@ def main():
     elif user_args['clear_ips'] is True:
         remove_ip_addresses(inventory, filepath)
         print('Success. . .')
+    elif user_args['remove_group']:
+        remove_inventory_group(user_args['remove_group'], inventory, filepath)
+        print('Success. . .')
     else:
         remove_inventory_item(user_args['remove_item'], inventory, filepath)
         print('Success. . .')