New function to expose variable address

[XieGuochao]

Terraform Version

Terraform v1.3.3
on linux_amd64

Use Cases

A function address would be useful and interesting to expose the absolute address of a variable or resource, especially when using in a module.

Suppose a resource vpc in a vcp module with the address module.vpc.aws_vpc.main, then calling the function address(aws_vpc.main) inside the module VPC returns a string "module.vpc.aws_vpc.main".

In different module instances, the result of calling address would be different. Like "module.vpc_one.aws_vpc.main" and "module.vpc_two.aws_vpc.main" for two usages of the VPC module.

This functionality would make a great difference in tag-based tracing, i.e. encode the absolute address in the resource tag, and many other use cases.

Attempted Solutions

The implementation is non-trivial and even this issue #2771 does not help implement this feature.

Proposal

It would be challenging to implement with the current Function interface because this function applies to a reference instead of a value.

References

No response

[crw]

Thanks for this feature request!