ec2 models get_zone_by_name KeyError when creating a Batch client

A pytest-based github action that depends on moto has started failing due to a traceback in ec2 models. The version of moto installed was:

Collecting moto[all]
Downloading moto-2.2.18-py2.py3-none-any.whl (1.5 MB)

The full traceback was:

______________________ ERROR at setup of test_blackboard _______________________

aws_credentials = None

    @pytest.fixture(scope="function")
    def batch_client(aws_credentials):
>       with mock_batch():

tests/conftest.py:52: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/__init__.py:17: in f
    module = importlib.import_module(module_name, "moto")
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/batch/__init__.py:1: in <module>
    from .models import batch_backends
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/batch/models.py:14: in <module>
    from moto.ec2 import ec2_backends
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/__init__.py:1: in <module>
    from .models import ec2_backends
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/models.py:8729: in <module>
    region.name: EC2Backend(region.name) for region in RegionsAndZonesBackend.regions
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/models.py:8729: in <dictcomp>
    region.name: EC2Backend(region.name) for region in RegionsAndZonesBackend.regions
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/models.py:8624: in __init__
    super().__init__()
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/models.py:1141: in __init__
    super().__init__()
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/models.py:1374: in __init__
    super().__init__()
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/models.py:1390: in __init__
    super().__init__()
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/models.py:1513: in __init__
    super().__init__()
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/models.py:3470: in __init__
    super().__init__()
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/models.py:1743: in __init__
    self._load_amis()
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/models.py:1752: in _load_amis
    self.amis[ami_id] = Ami(self, **ami)
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/models.py:1701: in __init__
    volume = self.ec2_backend.create_volume(size=15, zone_name=region_name)
/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/models.py:3486: in create_volume
    zone = self.get_zone_by_name(zone_name)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <moto.ec2.models.EC2Backend object at 0x7f5d679f9710>
name = 'us-east-1a'

    def get_zone_by_name(self, name):
>       for zone in self.zones[self.region_name]:
E       KeyError: 'ap-southeast-3'

/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/moto/ec2/models.py:2209: KeyError

The github action in question is here: https://github.com/spacetelescope/calcloud/runs/4512515777?check_suite_focus=true

And the code that’s being executed when it fails seems to be this:

@pytest.fixture(scope="function")
def batch_client(aws_credentials):
    with mock_batch():
        yield boto3.client("batch", region_name="us-east-1")

The last run one week ago with the same source code worked fine, using moto 2.2.17

Collecting moto[all]
  Downloading moto-2.2.17-py2.py3-none-any.whl (1.5 MB)

https://github.com/spacetelescope/calcloud/runs/4434257100?check_suite_focus=true

[bblommers]

Thanks for raising this everyone - this is now fixed as of Moto >= 2.2.19.

[foxmulder900]

This change did the trick for me: https://github.com/spulec/moto/pull/4688

I just deduced what those values should be based on what they are for ap-southeast-1 & ap-southeast-2, so it would be good for someone to verify them a little more closely.