[cloud] Make ec2_vpc_nat_gateway results consistent (#24042)

Ensure newly created NAT gateways get converted to snake dict
Remove custom code, and associated test, for generating snake
dict and use `camel_dict_to_snake_dict`
Make use of `required_if` rather than bespoke parameter checks
Remove ec2_vpc_nat_gateway from pep8 legacy files list

lib/ansible/modules/cloud/amazon/ec2_vpc_nat_gateway.py

@@ -212,20 +212,16 @@ nat_gateway_addresses:
 
 from ansible.module_utils.basic import AnsibleModule
 from ansible.module_utils.ec2 import ec2_argument_spec, get_aws_connection_info, boto3_conn
+from ansible.module_utils.ec2 import camel_dict_to_snake_dict, HAS_BOTO3
 
 import datetime
 import random
-import re
 import time
 
-from dateutil.tz import tzutc
-
 try:
     import botocore
-    import boto3
-    HAS_BOTO3 = True
 except ImportError:
-    HAS_BOTO3 = False
+    pass  # caught by imported HAS_BOTO3
 
 DRY_RUN_GATEWAYS = [
     {
@@ -244,23 +240,6 @@ DRY_RUN_GATEWAYS = [
         "vpc_id": "vpc-12345678"
     }
 ]
-DRY_RUN_GATEWAY_UNCONVERTED = [
-    {
-        'VpcId': 'vpc-12345678',
-        'State': 'available',
-        'NatGatewayId': 'nat-123456789',
-        'SubnetId': 'subnet-123456789',
-        'NatGatewayAddresses': [
-            {
-                'PublicIp': '55.55.55.55',
-                'NetworkInterfaceId': 'eni-1234567',
-                'AllocationId': 'eipalloc-1234567',
-                'PrivateIp': '10.0.0.102'
-            }
-        ],
-        'CreateTime': datetime.datetime(2016, 3, 5, 5, 19, 20, 282000, tzinfo=tzutc())
-    }
-]
 
 DRY_RUN_ALLOCATION_UNCONVERTED = {
     'Addresses': [
@@ -275,45 +254,6 @@ DRY_RUN_ALLOCATION_UNCONVERTED = {
 DRY_RUN_MSGS = 'DryRun Mode:'
 
 
-def convert_to_lower(data):
-    """Convert all uppercase keys in dict with lowercase_
-
-    Args:
-        data (dict): Dictionary with keys that have upper cases in them
-            Example.. FooBar == foo_bar
-            if a val is of type datetime.datetime, it will be converted to
-            the ISO 8601
-
-    Basic Usage:
-        >>> test = {'FooBar': []}
-        >>> test = convert_to_lower(test)
-        {
-            'foo_bar': []
-        }
-
-    Returns:
-        Dictionary
-    """
-    results = dict()
-    if isinstance(data, dict):
-        for key, val in data.items():
-            key = re.sub(r'(([A-Z]{1,3}){1})', r'_\1', key).lower()
-            if key[0] == '_':
-                key = key[1:]
-            if isinstance(val, datetime.datetime):
-                results[key] = val.isoformat()
-            elif isinstance(val, dict):
-                results[key] = convert_to_lower(val)
-            elif isinstance(val, list):
-                converted = list()
-                for item in val:
-                    converted.append(convert_to_lower(item))
-                results[key] = converted
-            else:
-                results[key] = val
-    return results
-
-
 def get_nat_gateways(client, subnet_id=None, nat_gateway_id=None,
                      states=None, check_mode=False):
     """Retrieve a list of NAT Gateways
@@ -378,7 +318,7 @@ def get_nat_gateways(client, subnet_id=None, nat_gateway_id=None,
             gateways = client.describe_nat_gateways(**params)['NatGateways']
             if gateways:
                 for gw in gateways:
-                    existing_gateways.append(convert_to_lower(gw))
+                    existing_gateways.append(camel_dict_to_snake_dict(gw))
             gateways_retrieved = True
         else:
             gateways_retrieved = True
@@ -747,22 +687,22 @@ def create(client, subnet_id, allocation_id, client_token=None,
 
     try:
         if not check_mode:
-            result = client.create_nat_gateway(**params)["NatGateway"]
+            result = camel_dict_to_snake_dict(client.create_nat_gateway(**params)["NatGateway"])
         else:
-            result = DRY_RUN_GATEWAY_UNCONVERTED[0]
-            result['CreateTime'] = datetime.datetime.utcnow()
-            result['NatGatewayAddresses'][0]['AllocationId'] = allocation_id
-            result['SubnetId'] = subnet_id
+            result = DRY_RUN_GATEWAYS[0]
+            result['create_time'] = datetime.datetime.utcnow()
+            result['nat_gateway_addresses'][0]['Allocation_id'] = allocation_id
+            result['subnet_id'] = subnet_id
 
         success = True
         changed = True
-        create_time = result['CreateTime'].replace(tzinfo=None)
+        create_time = result['create_time'].replace(tzinfo=None)
         if token_provided and (request_time > create_time):
             changed = False
         elif wait:
             success, err_msg, result = (
                 wait_for_status(
-                    client, wait_timeout, result['NatGatewayId'], 'available',
+                    client, wait_timeout, result['nat_gateway_id'], 'available',
                     check_mode=check_mode
                 )
             )
@@ -949,7 +889,7 @@ def remove(client, nat_gateway_id, wait=False, wait_timeout=0,
     changed = False
     err_msg = ""
     results = list()
-    states = ['pending', 'available' ]
+    states = ['pending', 'available']
     try:
         exist, _, gw = (
             get_nat_gateways(
@@ -1023,7 +963,9 @@ def main():
         supports_check_mode=True,
         mutually_exclusive=[
             ['allocation_id', 'eip_address']
-        ]
+        ],
+        required_if=[['state', 'absent', ['nat_gateway_id']],
+                     ['state', 'present', ['subnet_id']]]
     )
 
     # Validate Requirements
@@ -1059,9 +1001,6 @@ def main():
     err_msg = ''
 
     if state == 'present':
-        if not subnet_id:
-            module.fail_json(msg='subnet_id is required for creation')
-
         success, changed, err_msg, results = (
             pre_create(
                 client, subnet_id, allocation_id, eip_address,
@@ -1070,16 +1009,12 @@ def main():
             )
         )
     else:
-        if not nat_gateway_id:
-            module.fail_json(msg='nat_gateway_id is required for removal')
-
-        else:
-            success, changed, err_msg, results = (
-                remove(
-                    client, nat_gateway_id, wait, wait_timeout, release_eip,
-                    check_mode=check_mode
-                )
+        success, changed, err_msg, results = (
+            remove(
+                client, nat_gateway_id, wait, wait_timeout, release_eip,
+                check_mode=check_mode
             )
+        )
 
     if not success:
         module.fail_json(

test/sanity/pep8/legacy-files.txt

@@ -136,7 +136,6 @@ lib/ansible/modules/cloud/amazon/ec2_vpc_dhcp_options.py
 lib/ansible/modules/cloud/amazon/ec2_vpc_igw.py
 lib/ansible/modules/cloud/amazon/ec2_vpc_nacl.py
 lib/ansible/modules/cloud/amazon/ec2_vpc_nacl_facts.py
-lib/ansible/modules/cloud/amazon/ec2_vpc_nat_gateway.py
 lib/ansible/modules/cloud/amazon/ec2_vpc_net.py
 lib/ansible/modules/cloud/amazon/ec2_vpc_net_facts.py
 lib/ansible/modules/cloud/amazon/ec2_vpc_peer.py

test/units/modules/cloud/amazon/test_ec2_vpc_nat_gateway.py

@@ -264,36 +264,6 @@ class AnsibleVpcNatGatewayTasks(unittest.TestCase):
 
 class AnsibleEc2VpcNatGatewayFunctions(unittest.TestCase):
 
-    def test_convert_to_lower(self):
-        example = ng.DRY_RUN_GATEWAY_UNCONVERTED
-        converted_example = ng.convert_to_lower(example[0])
-        keys = list(converted_example.keys())
-        keys.sort()
-        for i in range(len(keys)):
-            if i == 0:
-                self.assertEqual(keys[i], 'create_time')
-            if i == 1:
-                self.assertEqual(keys[i], 'nat_gateway_addresses')
-                gw_addresses_keys = list(converted_example[keys[i]][0].keys())
-                gw_addresses_keys.sort()
-                for j in range(len(gw_addresses_keys)):
-                    if j == 0:
-                        self.assertEqual(gw_addresses_keys[j], 'allocation_id')
-                    if j == 1:
-                        self.assertEqual(gw_addresses_keys[j], 'network_interface_id')
-                    if j == 2:
-                        self.assertEqual(gw_addresses_keys[j], 'private_ip')
-                    if j == 3:
-                        self.assertEqual(gw_addresses_keys[j], 'public_ip')
-            if i == 2:
-                self.assertEqual(keys[i], 'nat_gateway_id')
-            if i == 3:
-                self.assertEqual(keys[i], 'state')
-            if i == 4:
-                self.assertEqual(keys[i], 'subnet_id')
-            if i == 5:
-                self.assertEqual(keys[i], 'vpc_id')
-
     def test_get_nat_gateways(self):
         client = boto3.client('ec2', region_name=aws_region)
         success, err_msg, stream = (