feat(remote-state): enable assume_role block in backend configuration to fix deprecation warning

[kevcube]

what

Solves a deprecation warning for using role_arn parameter instead of assume_role configuration block.
Doesn't use the complicated negation-of-try-contains ternary logic.. but it seems to work whether the value is present or not, being backwards compatible and not erroring if people don't have assume_role blocks in their configuration. Please test because you guys are more familiar with the usage of this module than I am.

why

I was receiving this deprecation warning and wanted to silence it.

references

https://developer.hashicorp.com/terraform/language/settings/backends/s3#role_arn-1

[osterman]

@kevcube according to @Nuru

With Terraform 1.6.0, the configuration block for the S3 backend changed.

role_arn = <role to assume>

changed to:

assume_role = {
  role_arn = <role to assume>
}

(other things, moved, too.)

The PR probably won't actually work. The proper fix breaks Terraform 1.5.7 and MPL licensed terraform (e.g. OpenTofu)

│ The given configuration is not valid for backend "s3": unexpected attribute "assume_role".

Confirm it works with

• SuperAdmin
• Without requiring assumed roles

[osterman]

To be clear, we want to fix this - we just don't know how to given the incompatibilities between MPL licensed terraform and BSL licensed terraform (>= 1.6.x).

[mergify]

Important

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[osterman]

This might make this easier:

In addition to supporting .tf extension files as we do today, OpenTofu will support .tofu extension files. When two files have the same name, one with the .tf extension and one with the .tofu extension, OpenTofu will load only the .tofu file and ignore the .tf file. Hence, creating a mechanism that overrides specific files. This way the .tofu extension files will be used for OpenTofu specific features and syntax and the .tf extension files can be used for Terraform compatible features and syntax. Allowing users and module maintainers to use OpenTofu and Terraform in the same project without conflicts.

https://github.com/opentofu/opentofu/pull/1699/files

[Nuru]

@kevcube I'm sorry if the labels seem harsh; they do not allow for a lot of nuance. All I mean by them is that this is not the way to fix the problem, and we are not going to go down this path.

I am going to close this PR so it does not get merged. If you want to open an issue about the deprecation warning, that would be fine, and we will address it in the near (but not immediate) future.

[osterman]

This feature is making it's way into OpenTofu 1.8 (I hope!)

opentofu/opentofu#1738

[kevcube]

This feature is making it's way into OpenTofu 1.8 (I hope!)

opentofu/opentofu#1738

The issue would still be present for Terraform users though

[Nuru]

Fixed by #105 released in v1.8.0