ec2_vpc_igw: fix NoneType error

changelogs/fragments/695-ec2_vpc_igw-add-manual-waiter.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - ec2_vpc_igw - add manual waiter to fix 'NoneType' object is not subscriptable error (https://github.com/ansible-collections/amazon.aws/pull/695).

plugins/modules/ec2_vpc_igw.py

@@ -110,6 +110,9 @@
 from ..module_utils.ec2 import ensure_ec2_tags
 from ..module_utils.ec2 import ansible_dict_to_boto3_filter_list
 from ..module_utils.tagging import boto3_tag_list_to_ansible_dict
+from time import sleep
+from time import time
+from random import randint
 
 
 class AnsibleEc2Igw():
@@ -152,6 +155,31 @@ def get_matching_igw(self, vpc_id):
 
         return igw
 
+    def wait_for_igw(self, vpc_id):
+        """
+        Waits for existing igw to be returned via describe_internet_gateways
+        in get_matching_igw with exponential backoff
+        :param vpc_id: VPC's ID
+        :return igw: igw found
+        """
+        max_backoff = 64
+        timeout = 3000
+        failure_counter = 0
+        start_time = time()
+
+        while True:
+            if time() - start_time >= timeout:
+                self._module.fail_json(msg='Error finding Internet Gateway in VPC {0} - please check the AWS console'.format(vpc_id))
+            try:
+                igw = self.get_matching_igw(vpc_id)
+                if igw:
+                    return igw
+                sleep_time = min(2 ** failure_counter + randint(1, 1000) / 1000, max_backoff)
+                sleep(sleep_time)
+                failure_counter += 1
+            except (botocore.exceptions.ClientError, botocore.exceptions.BotoCoreError) as e:
+                self._module.fail_json_aws(e, msg='Failure while waiting for status update')
+
     @staticmethod
     def get_igw_info(igw, vpc_id):
         return {
@@ -218,11 +246,21 @@ def ensure_igw_present(self, vpc_id, tags, purge_tags):
             except (botocore.exceptions.ClientError, botocore.exceptions.BotoCoreError) as e:
                 self._module.fail_json_aws(e, msg='Unable to create Internet Gateway')
 
-        self._results['changed'] |= ensure_ec2_tags(
+        # Ensure we can get igw object prior to modifying tags
+        igw = self.wait_for_igw(vpc_id)
+
+        # Modify tags
+        tags_changed = ensure_ec2_tags(
             self._connection, self._module, igw['internet_gateway_id'],
             resource_type='internet-gateway', tags=tags, purge_tags=purge_tags
         )
-        igw = self.get_matching_igw(vpc_id)
+        self._results['changed'] |= tags_changed
+
+        # Wait for igw again if tags were modified to be safe
+        if tags_changed:
+            igw = self.wait_for_igw(vpc_id)
+
+        # Update igw
         igw_info = self.get_igw_info(igw, vpc_id)
         self._results.update(igw_info)