Fetching SSO IAM role ARNs dynamically

[mattdodge]

Community Note

• Please vote on this issue by adding a 👍 reaction to the original issue to help the community and maintainers prioritize this request
• Please do not leave "+1" or other comments that do not add relevant new information or questions, they generate extra noise for issue followers and do not help prioritize the request
• If you are interested in working on this issue or have submitted a pull request, please leave a comment

Terraform CLI and Terraform AWS Provider Version

Terraform v0.12.19
+ provider.aws v2.61.0

Affected Resource(s)

• aws_iam_role

Expected Behavior

We're using AWS SSO to authenticate into our different AWS accounts. This creates roles in each account that maps to the permission sets in AWS SSO. I'm wondering how I can get these role names in a dynamic fashion in terraform.

For example, I want to allow our developers access to our Kubernetes cluster. I do this by creating a role that has access that a developer can call AssumeRole on, like so.

resource "aws_iam_role" "developer_cluster_access" {
  name                 = "cluster-access-developer"
  assume_role_policy   = data.aws_iam_policy_document.developer_cluster_access.json
}

data "aws_iam_policy_document" "developer_cluster_access" {
  statement {
    actions = ["sts:AssumeRole"]
    principals {
      type = "AWS"
      identifiers = ["my_role_arn_goes_here"]  # <-- I want this to be dynamic
    }
  }
}

Right now I'm having to hard code that role ARN in the assume role policy document - I would like for this to be fetched dynamically.

I could use the aws_iam_role data source but for that I need the role name. The name structure of the role seems to be something like AWSReservedSSO_<permission set>_<unique hash> (Example role name: AWSReservedSSO_AWSPowerUserAccess_aaaaaabbbbbbcccc). Is there a reliable/deterministic way to compute that hash in terraform?

[sidewinder12s]

Anyone know how easy it might be to update the aws_iam_role data source to search for roles based on part of the name or by tags?

[Marcvd316]

This issue is nearly identical to the one I opened in August last year : #14470. Maybe they should be merged?

[seddarj]

I believe #18048 would fix this issue 😅

[github-actions]

This functionality has been released in v3.55.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.
If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.