I'm looking to reuse cloudformation infrastructure with aws.cloudformation.Stack() resources. aws.cloudformation.Stack has a limit on the template size on disk after which you have to upload it to s3 and give it an s3 uri. Is there anything already in pulumi I can use to upload templates to a temporary place in s3 to be able to use with aws.cloudformation.Stack ?

Yeah -

aws.s3.BucketObject

will upload a local file to S3. This is used in many examples in

pulumi/examples

repo.

but then that becomes a resource that is part of the managed infrastructure right?

Yes - and it is versioned as updates are needed - and cleaned up when infrastructure is deleted.