nxos_hsrp: fix 'sh_preempt': <unknown enum:> (#52858)

* nxos_hsrp: fix 'sh_preempt': <unknown enum:>

Some older nxos images fail to set this attr value. This fix checks for
unknown enum and issues a second (unstructured) call to the device to get
the data.

* add whitespace for pep8

(cherry picked from commit 5dc65d0dfc)

lib/ansible/modules/network/nxos/nxos_hsrp.py

@@ -211,6 +211,8 @@ def get_hsrp_group(group, interface, module):
     try:
         body = run_commands(module, [command])[0]
         hsrp_table = body['TABLE_grp_detail']['ROW_grp_detail']
+        if 'unknown enum:' in str(hsrp_table):
+            hsrp_table = get_hsrp_group_unknown_enum(module, command, hsrp_table)
     except (AttributeError, IndexError, TypeError, KeyError):
         return {}
 
@@ -239,6 +241,19 @@ def get_hsrp_group(group, interface, module):
     return hsrp
 
 
+def get_hsrp_group_unknown_enum(module, command, hsrp_table):
+    '''Some older NXOS images fail to set the attr values when using structured output and
+    instead set the values to <unknown enum>. This fallback method is a workaround that
+    uses an unstructured (text) request to query the device a second time.
+    'sh_preempt' is currently the only attr affected. Add checks for other attrs as needed.
+    '''
+    if 'unknown enum:' in hsrp_table['sh_preempt']:
+        cmd = {'output': 'text', 'command': command.split('|')[0]}
+        out = run_commands(module, cmd)[0]
+        hsrp_table['sh_preempt'] = 'enabled' if ('may preempt' in out) else 'disabled'
+    return hsrp_table
+
+
 def get_commands_remove_hsrp(group, interface):
     commands = ['interface {0}'.format(interface), 'no hsrp {0}'.format(group)]
     return commands