AWS allows only the case-sensitive strings `Allow` and `Deny` to appear
in the `Effect` fields of IAM policy documents. Catch deviations from
this, including mis-casing, before hitting the API and generating an
error (the error is a generic 400 and doesn't indicate what part of the
policy doc is invalid).
* Various string slices are sorted and truncated to strings if they
only contain one element.
* Sids are now included if they are empty.
This is to ensure what is sent to AWS matches what comes back, to
prevent recurring diffs even when the policy has changed.
We cannot use the "id" field to represent policy ID, because it is used
internally by Terraform. Also change the "id" field within a statement
to "sid" for consistency with the generated JSON.
This brings over the work done by @apparentlymart and @radeksimko in
PR #3124, and converts it into a data source for the AWS provider:
This commit adds a helper to construct IAM policy documents using
familiar Terraform concepts. It makes Terraform-style interpolations
easier and resolves the syntax conflict between Terraform interpolations
and IAM policy variables by changing the latter to use &{...} for its
interpolations.
Its use is completely optional and users are free to go on using literal
heredocs, file interpolations or whatever else; this just adds another
option that fits more naturally into a Terraform config.
Doug Neal