Error: Resource's path part only allow [a-zA-Z0-9:._-], an optional trailing '+'(module name)

[fd008]

Describe the bug

CDK v2 api gateway won't allow "$" sign in the url, but it "$" is allows using AWS CLI and Console

Error: Resource's path part only allow [a-zA-Z0-9:._-], an optional trailing '+'
and curly braces at the beginning and the end: $test
at validateResourcePathPart

Expected Behavior

No error when using $ in the api path just like AWS CLI or Console

Current Behavior

Error: Resource's path part only allow [a-zA-Z0-9:._-], an optional trailing '+'
and curly braces at the beginning and the end: $process-message
at validateResourcePathPart

Reproduction Steps

const restApi = new RestApi(this, 'restApi', {
deploy: true,
})

restApi.root?.addResource("$test")

Possible Solution

No response

Additional Information/Context

No response

CDK CLI Version

2.95.1 (build ae455d8)

Framework Version

No response

Node.js Version

v18.16.1

OS

Ubuntu 22.04.2 LTS

Language

Typescript

Language Version

5.2.2

Other information

No response

[indrora]

If I understand this right, this is a CloudFormation limitation, not a CDK limitation at its heart.

The CLI and Console do not interact with CloudFormation, thus are not subject to its limitations.

[peterwoodworth]

@indrora are there any docs from CloudFormation stating this limitation? Have we tried working around this with escape hatches to confirm?

[indrora]

• Logical IDs can only have alphanumeric characters: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/resources-section-structure.html
• the Name type must be only ASCII letters, digits, and hyphens: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-name.html
• $ is part of Fn::Sub and has Weird rules: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-sub.html

[peterwoodworth]

I see, the issue is that we are taking whatever is passed into addResource() and are directly adding it to the logical ID.

There isn't any issue with setting the pathPart to be accurate with an escape hatch:

    const restApi = new apigw.RestApi(this, 'restApi', {
      deploy: true,
    });
      
    const apiResource = restApi.root?.addResource("testwithoutdollar");
    (apiResource.node.defaultChild as apigw.CfnResource).addPropertyOverride('PathPart', '$testwithoutdollar');
    restApi.root.addMethod('GET');

Deploying this results in the following:

I think it should work fine if we change the code found at validateResourcePathPart. We've had to make this more lenient in the past #22531

aws-cdk/packages/aws-cdk-lib/aws-apigateway/lib/resource.ts

Line 550 in ae455d8

function validateResourcePathPart(part: string) {

Edit: Actually, on a further look, special characters like : or $ get sanitized out of the synthesized logical IDs anyway. Scratch anything related to that

[lawofcycles]

I may be able to implement this fix.

[github-actions]

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