rossetta issue: varargs are ignored when hoisting keyword arguments

[thomaspoignant]

Original title: cluster.add_resource got an unexpected keyword argument 'api_version'

Using Python when I try to add a resource using the example available here I have an error during the execution.

The error is :

TypeError: add_resource() got an unexpected keyword argument 'api_version'

Reproduction Steps

Create a stack with this

cluster = eks.Cluster(self, "hello-eks",
    version=eks.KubernetesVersion.V1_16
)

cluster.add_resource("mypod",
    api_version="v1",
    kind="Pod",
    metadata={"name": "mypod"},
    spec={
        "containers": [{
            "name": "hello",
            "image": "paulbouwer/hello-kubernetes:1.5",
            "ports": [{"container_port": 8080}]
        }
        ]
    }
)

and run cdk synth.

Error Log

TypeError: add_resource() got an unexpected keyword argument 'api_version'

Environment

• CLI Version: aws-cli/2.0.33 Python/3.8.5 Darwin/19.6.0 botocore/2.0.0dev37
• Framework Version: 1.54.0 (build c01b9b9)
• Node.js Version: v14.5.0
• OS : Mac OSX 10.15.6*
• Language (Version): Python 3.8.5

---

This is 🐛 Bug Report

[eladb]

The add_resource API accepts a variable number of manifest arguments as objects and not through keyword arguments:

cluster.add_resource('MyResource', {
    "api_version": "v1",
    "kind": "Pod",
    "metadata": {"name": "mypod"},
    "spec": {
        "containers": [{
            "name": "hello",
            "image": "paulbouwer/hello-kubernetes:1.5",
            "ports": [{"container_port": 8080}]
        }]
    }
})

[thomaspoignant]

@eladb I understand that you closed the issue, but the code snippet is directly from the documentation (see the link in my previous comment).

https://docs.aws.amazon.com/cdk/api/latest/python/aws_cdk.aws_eks.README.html

[eladb]

Good point. The docs should be fixed. Reopening to track

[eladb]

The root cause is that auto-generated documentation in Python does not take into account the fact that manifest is a variable arguments array and hoists the typescript struct to keyword arguments.

Related: #826

Transferring to the jsii repo for follow up.

[thomaspoignant]

Thanks for the reassignment @eladb.

[thomaspoignant]

For information, if someone has the same problems, the correct syntax is bellow.

api_version should be apiVersion,
You should use camel case not snake case.

cluster.add_resource('MyResource', {
    "apiVersion": "v1",
    "kind": "Pod",
    "metadata": {"name": "mypod"},
    "spec": {
        "containers": [{
            "name": "hello",
            "image": "paulbouwer/hello-kubernetes:1.5",
            "ports": [{"container_port": 8080}]
        }]
    }
})

[RomainMuller]

The original type signature is the following:

addResource(id: string, ...manifest: any[]): KubernetesResource

This particular example was generated without compilation, so it did not have access to the type information during transliteration. The first thing we should attempt is trying to make the original version compilable and see whether this fixes it.

[RomainMuller]

Turns out even with type information the "bad" code would be generated in this case... I've submitted a PR to address that.

[RomainMuller]

Note - in order for the documentation to actually be fixed, the example code must be made compilable (otherwise the type information needed to determine the call is variadic will not be available).

This can be achieved by dropping a rosetta/default.ts-fixture in the package which provides the necessary wrapping code so jsii-rosetta can have type info.

The necessary fix will be available in jsii's next release (1.10.0), but the fixture can be introduced before then - the translated example will simply keep being broken until CDK uses the fixed release.

[RomainMuller]

This is actually fixed in aws/aws-cdk@3c116f3 where I inadvertently committed a fixture...