How to use FnImportValue where CDK wants a string or list of string?

Hi,

I’m trying to import a VPC from an existing (non-cdk) stack, following the examples in: https://gist.github.com/mipearson/aeaf303b0770c25f8b5f6e360594cfbf https://github.com/awslabs/aws-cdk/issues/603 https://github.com/awslabs/aws-cdk/issues/506

I added exports in my existing stack for the VPC ID, CIDR block, availability zones, and subnets.

In order to call VpcNetworkRef.import_, I need to pass it VpcNetworkRefProps, and the builder for the props wants a list of strings for AZs.

None of these type check as arguments to VpcNetworkRefProps.builder().withVpcId(id).withAvailabilityZones:

• new FnImportValue("other-stack-AZs") where other-stack-AZs is a comma-separated export (Fn::Join on the other stack’s cloudformation template)
• new FnSplit(",", new FnImportValue("other-stack-AZs"))
• [new FnImportValue("other-stack-AZ1"), new FnImportValue("other-stack-AZ2"), new FnImportValue("other-stack-AZ3")]

How can I import availability zones from another stack?

And more generally, how should we use FnImportValue where CDK wants a string or a list of strings?

[eladb]

I don’t think we need a general-purpose solution, just support for string arrays.

[rix0rrr]

We could extend Token stringification to have different encodings for different types… but the types would have to be known beforehand which we also don’t have.

With the type system that we have, not much we can do I think.