Error using event-rule invalid-targets filter

Describe the bug

Attempting to clean up event rules with invalid targets, c7n throws an error “TypeError: argument of type ‘NoneType’ is not iterable”

What did you expect to happen?

run the policy without crashing

Cloud Provider

Amazon Web Services (AWS)

Cloud Custodian version and dependency information

Custodian:   0.9.17
Python:      3.7.9 (v3.7.9:13c94747c7, Aug 15 2020, 01:31:08) 
             [Clang 6.0 (clang-600.0.57)]
Platform:    posix.uname_result(sysname='Darwin', nodename='38f9d3ae684c', release='20.6.0', version='Darwin Kernel Version 20.6.0: Tue Apr 19 21:04:45 PDT 2022; root:xnu-7195.141.29~1/RELEASE_X86_64', machine='x86_64')
Using venv:  False
Docker: False
Installed: 

argcomplete==1.12.3
attrs==19.1.0
boto3==1.21.8
botocore==1.24.8
cffi==1.13.2
cryptography==36.0.1
importlib-metadata==4.11.1
jmespath==0.9.4
jsonschema==3.2.0
more-itertools==7.2.0
pycparser==2.19
pyrsistent==0.15.4
python-dateutil==2.8.2
pyyaml==6.0
s3transfer==0.5.2
setuptools==47.1.0
six==1.12.0
tabulate==0.8.7
typing-extensions==4.1.1
urllib3==1.26.8
zipp==0.6.0

Policy

policies:
  - name: event-rule-invalid-target
    resource: event-rule
    filters:
      - type: value
        key: ManagedBy
        op: not-in
        value: 'amazonaws.com'
        value_type: swap
      - type: invalid-targets
        all: true 
    actions:
      - type: delete
        force: true

Relevant log/traceback output

% custodian run --cache-period=30 --profile myProfile -v -s ~/c7nout -c test.yml -p event-rule-invalid-target -r us-east-1     
2022-07-06 17:08:34,722: custodian.commands:DEBUG Loaded file test.yml. Contains 16 policies
2022-07-06 17:08:36,491: custodian.output:DEBUG Storing output with <LogFile file:///Users/john_wick/c7nout/event-rule-invalid-target/custodian-run.log>
2022-07-06 17:08:36,503: custodian.policy:DEBUG Running policy:event-rule-invalid-target resource:event-rule region:us-east-1 c7n:0.9.17
2022-07-06 17:08:36,511: custodian.cache:DEBUG Using cache file /Users/john_wick/.cache/cloud-custodian.cache
2022-07-06 17:08:36,511: custodian.resources.eventrule:DEBUG Using cached c7n.resources.cw.EventRule: 1989
2022-07-06 17:16:55,368: custodian.cache:DEBUG Using cache file /Users/john_wick/.cache/cloud-custodian.cache
...
2022-07-06 17:18:37,849: custodian.cache:DEBUG Using cache file /Users/john_wick/.cache/cloud-custodian.cache
len(identities) != 1. Actual value: 2
identities:
['AccountServiceListenerQueue', 'AccountServiceListenerQueue']
2022-07-06 17:18:39,524: custodian.cache:DEBUG Using cache file /Users/john_wick/.cache/cloud-custodian.cache
...
2022-07-06 17:18:44,685: custodian.cache:DEBUG Using cache file /Users/john_wick/.cache/cloud-custodian.cache
2022-07-06 17:18:46,319: custodian.output:DEBUG metric:PolicyException Count:1 policy:event-rule-invalid-target restype:event-rule
2022-07-06 17:18:46,319: custodian.output:DEBUG metric:ApiCalls Count:1858 policy:event-rule-invalid-target restype:event-rule
2022-07-06 17:18:46,319: custodian.output:ERROR Error while executing policy
Traceback (most recent call last):
  File ".../site-packages/c7n/policy.py", line 290, in run
    resources = self.policy.resource_manager.resources()
  File ".../site-packages/c7n/query.py", line 536, in resources
    resources = self.filter_resources(resources)
  File ".../site-packages/c7n/manager.py", line 111, in filter_resources
    resources = f.process(resources, event)
  File ".../site-packages/c7n/resources/cw.py", line 249, in process
    resolved = arn_resolver.resolve(r['c7n:ChildArns'])
  File ".../site-packages/c7n/resources/aws.py", line 180, in resolve
    rmanager = self.manager.get_resource_manager(rtype)
  File ".../site-packages/c7n/manager.py", line 82, in get_resource_manager
    if '.' in resource_type:
TypeError: argument of type 'NoneType' is not iterable
2022-07-06 17:18:46,325: custodian.commands:ERROR Error while executing policy event-rule-invalid-target, continuing
Traceback (most recent call last):
  File ".../site-packages/c7n/commands.py", line 301, in run
    policy()
  File ".../site-packages/c7n/policy.py", line 1242, in __call__
    resources = mode.run()
  File ".../site-packages/c7n/policy.py", line 290, in run
    resources = self.policy.resource_manager.resources()
  File ".../site-packages/c7n/query.py", line 536, in resources
    resources = self.filter_resources(resources)
  File ".../site-packages/c7n/manager.py", line 111, in filter_resources
    resources = f.process(resources, event)
  File ".../site-packages/c7n/resources/cw.py", line 249, in process
    resolved = arn_resolver.resolve(r['c7n:ChildArns'])
  File ".../site-packages/c7n/resources/aws.py", line 180, in resolve
    rmanager = self.manager.get_resource_manager(rtype)
  File ".../site-packages/c7n/manager.py", line 82, in get_resource_manager
    if '.' in resource_type:
TypeError: argument of type 'NoneType' is not iterable
2022-07-06 17:18:46,326: custodian.commands:ERROR The following policies had errors while executing
 - event-rule-invalid-target

Extra information or context

I got the policy working by adding “if rtype is not None:” at line 180 in the resolve method of ArnResolver Class in aws.py, like this:

   def resolve(self, arns):
        arns = map(Arn.parse, arns)
        a_service = operator.attrgetter('service')
        a_resource = operator.attrgetter('resource_type')
        kfunc = lambda a: (a_service(a), a_resource(a))  # noqa
        arns = sorted(arns, key=kfunc)
        results = {}
        for (service, arn_type), arn_set in itertools.groupby(arns, key=kfunc):
            arn_set = list(arn_set)
            rtype = ArnResolver.resolve_type(arn_set[0])
            if rtype is not None:
                rmanager = self.manager.get_resource_manager(rtype)
                if rtype == 'sns':
                    resources = rmanager.get_resources(
                        [rarn.arn for rarn in arn_set])
                else:
                    resources = rmanager.get_resources(
                        [rarn.resource for rarn in arn_set])
                for rarn, r in zip(rmanager.get_arns(resources), resources):
                    results[rarn] = r

                for rarn in arn_set:
                    if rarn.arn not in results:
                        results[rarn.arn] = None
        return results

[kapilt]

Ah, thanks! I think we have a bunch of resources that can be targets and are not supported in custodian as of today. Other resources are inspector-template, states . For now I can go ahead and do what you suggested

sounds good, but fwiw, states we can handle as its a step function resource.

[kapilt]

Sure, go for it, thanks