Add AWS QUERY protocol support

[arandito]

Description

This PR adds awsQuery support: a new protocol generator and protocol-test projection, plus smithy-aws-core runtime client protocol support with URL form-encoded request serialization and modeled awsQueryError handling for awsQuery services.

It also includes supporting infrastructure changes: generated operation error schema registration, SigV4 protocol-test config for AWS protocol tests, and shared protocol-test handling for application/x-www-form-urlencoded bodies.

Note

This PR includes a couple changes that are directly ported from the currently open AWS JSON protocol PR #645. This PR will be rebased once the other is merged.

Testing

All supported protocol tests are passing. Tests in the explicit skip list remain skipped because they cover features that are not yet supported.

I was also able to generate a client for AWS STS from its Smithy service model and make a successful call:

STS test script

import asyncio

from smithy_aws_core.identity import EnvironmentCredentialsResolver

from aws_sdk_sts.client import STSClient
from aws_sdk_sts.config import Config
from aws_sdk_sts.models import GetCallerIdentityInput


async def main():
    client = STSClient(
        config=Config(
            endpoint_uri="https://sts.us-west-2.amazonaws.com",
            region="us-west-2",
            aws_credentials_identity_resolver=EnvironmentCredentialsResolver(),
        )
    )
    response = await client.get_caller_identity(GetCallerIdentityInput())

    print(response)


asyncio.run(main())

Output

> python test.py
/Users/aearanda/repos/github/smithy-python/packages/aws_sdk_signers/signers.py:794: AWSSDKWarning: Payload signing is enabled. This may result in decreased performance for large request bodies.
  warnings.warn(
Unclosed client session
client_session: <aiohttp.client.ClientSession object at 0x106caa240>
GetCallerIdentityOutput(user_id='<REDACTED>', account='<REDACTED>', arn='<REDACTED>')

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[jonathan343]

How are we able to make this without httpResponseCode which should be required? Also not something we need to solve now. But I think this might affect all other traits and we should look into it as a separate task.

[arandito]

It's most likely because the base Trait class doesn't invoke the trait's __post_init__ to actual call the assertions for required members.

I will create an issue/backlog item to get this addressed. I updated the test to include httpResponseCode in the meantime.

[jonathan343]

I'm not a fan of this conditional class definition but I don't think it's a blocking comment.

For a follow-up, I’d move AWSJSONDocument into a small JSON-specific module and import it alongside JSONCodec at the optional-dependency boundary. That would keep the same behavior while making the structure cleaner.

[arandito]

I'm not of fan either. We definitely need to centralize how we guard against optional dependencies in general. I had to repeat the same xml conditional logic for _private.query.errors to get around the optional smithy-xml import.

I took some time to see the effort required but it does extend to the smithy-http package with our optional dependencies on crt and aiohttp. This is definitely a larger effort that fell out of the scope of this PR.

Something we should address before add CBOR support.