I have a CDK app in which I create a Sagemaker endpoint using CfnEndpoint. When I omit the name parameter, CDK generates me a unique one which is great.

我有一个CDK应用程序，其中我使用CfnEndpoint创建了一个Sagemaker端点。当我省略name参数时，CDK会为我生成一个非常棒的唯一参数。

const endpoint = new CfnEndpoint(this, "Endpoint", {
  endpointConfigName: endpointConfig.attrEndpointConfigName,
});

The problem comes when I want to grant something permissions to invoke the endpoint in another stack. I want to grant a lambda function permissions to invoke just that endpoint and not others, so I would usually do something like:

当我想授予某些权限来调用另一个堆栈中的端点时，问题就出现了。我想授予一个lambda函数只调用该端点而不调用其他端点的权限，所以我通常会这样做：

myFunction.addToRolePolicy(new PolicyStatement({
  effect: Effect.ALLOW,
  actions: ['sagemaker:InvokeEndpoint'],
  resources: [Stack.of(this).formatArn({
    service: 'sagemaker',
    resource: 'endpoint',
    resourceName: endpoint.attrEndpointName, // <- reference the endpoint name from another stack
  })],
}));

The problem is that when I do this, the arn resolves with a mixed case endpoint name:

问题是，当我这样做时，ARN使用大小写混合的端点名称进行解析：

arn:aws:sagemaker:ap-southeast-2:012345678910:endpoint/Endpoint3015B993-FcX1jFxPQKeE

Arn:aws:sagemaker:ap-southeast-2:012345678910:endpoint/Endpoint3015B993-FcX1jFxPQKeE

And my lambda is not granted the appropriate permissions, as the name needs to be completely lowercase to do this.

而且我的lambda没有被授予适当的权限，因为名称需要完全小写才能做到这一点。

I've also tried using the Fn::Transform CloudFormation macro like so:

我还尝试使用FN：：Transform CloudForformation宏，如下所示：

myFunction.addToRolePolicy(new PolicyStatement({
  effect: Effect.ALLOW,
  actions: ['sagemaker:InvokeEndpoint'],
  resources: [Stack.of(this).formatArn({
    service: 'sagemaker',
    resource: 'endpoint',
    resourceName: Fn.transform('String', {
      Operation: "Lower",
      InputString: endpoint.attrEndpointName,
    }),
  })],
}));

But this throws an error when I attempt to deploy:

但这在我尝试部署时抛出了一个错误：

Error: Failed to create ChangeSet cdk-deploy-change-set on MyStack: FAILED, The value of parameter InputString under transform String must resolve to a string, number, boolean or a list of any of these.

It sounds like that transform only works on static values or cloudformation inputs.

听起来，该转换只对静态值或CloudForment输入有效。

Does anyone know a way I can construct an arn with a lowercase endpoint name?

有谁知道我可以用小写的端点名称构造ARN的方法吗？

I don't really want to hardcode a name for my endpoint, and a custom resource lambda feels like overkill, but I suppose either of those would sort it.

我真的不想为我的端点硬编码一个名称，定制资源lambda感觉有点矫枉过正，但我想这两个都可以解决这个问题。

Here's something that works, but feels overkill with a lambda function:

下面是一些有用的东西，但使用lambda函数感觉有点过头了：

const endpointArnCustomResource = new CustomResource(this, "EndpointArnCustomResource", {
  properties: {
    endpointArn: Stack.of(this).formatArn({
      service: "sagemaker",
      resource: "endpoint",
      resourceName: endpoint.attrEndpointName,
    }),
  },
  serviceToken: new Provider(this, "EndpointArnProvider", {
    onEventHandler: new Function(this, "EndpointArnFunction", {
      runtime: Runtime.NODEJS_18_X,
      handler: "index.handler",
      code: Code.fromInline(`exports.handler = async (event) => {
        return {
          PhysicalResourceId: event.PhysicalResourceId,
          Data: {
            endpointArn: event.ResourceProperties.endpointArn.toLowerCase(),
          },
        };
      }`)
    }),
  }).serviceToken,
});

// This has the endpoint arn in lowercase
const endpointArn = endpointArnCustomResource.getAttString("endpointArn");