Error when I try to use scaffolding to create shield

[archinksagar]

I tried the following command and selected shield, it creates one operation but gives an error.
python3 scripts/scaffold.py

Traceback (most recent call last):
  File "moto/scripts/scaffold.py", line 694, in <module>
    main()
  File "moto/.venv/lib/python3.12/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "moto/.venv/lib/python3.12/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/moto/.venv/lib/python3.12/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "moto/.venv/lib/python3.12/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "moto/scripts/scaffold.py", line 663, in main
    operation = select_operation(service)
                ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "moto/scripts/scaffold.py", line 92, in select_operation
    implemented, operation_names = get_operations(service_name)
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "moto/scripts/scaffold.py", line 109, in get_operations
    moto_client, _name = get_moto_implementation(service_name)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "moto/scripts/implementation_coverage.py", line 21, in get_moto_implementation
    else backends[0]["global"]
         ~~~~~~~~~~~^^^^^^^^^^
  File "moto/moto/core/base_backend.py", line 295, in __getitem__
    return super().__getitem__(region_name)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
KeyError: 'aws'

[bblommers]

Hi @archinksagar,

if you change the last line in moto/shield/models.py from:

shield_backends = BackendDict(ShieldBackend, "shield")

to

shield_backends = BackendDict(ShieldBackend, "ec2")

it should work again, and you can continue to use scripts/scaffold.py for other methods.

---

The argument is used to retrieve the list of regions that this service is available in, using boto3. The problem here is that boto3 exposes an empty list - i.e., it thinks that shield is not available in any region.

Changing it to ec2 ensures that boto3 (and therefore Moto) has a list of regions where shield is available. (ec2 is available in more regions than shield, so it's not entirely correct, but it's a good enough solution.)

Related: #6078

[archinksagar]

Thanks for the solution, it worked!

[bblommers]

Great, happy to hear that @archinksagar. I'll close this then, but let us know if you run into any other issues!