Get Subnet ARNs by Tag

get_subnet_arns_by_tag.tf

#This was an interesting thing I was trying to figure out. I used this to pass into a IAM Policy Resource Limit

# Get all of the subents with tag packer; returns a set of ids
data "aws_subnet_ids" "this" {
  vpc_id = var.vpc_id
  tags = {
    tag_name = "tag_value"
  }
}

#Get the arns for each subnet
data "aws_subnet" "this" {
  for_each = data.aws_subnet_ids.this.ids
  id       = each.key
}

output "subnet_ids" {
  value = data.aws_subnet_ids.this.ids
}

# This value here can then be sent to another resource for use as a list of arns
output "subnet_arns" {
  value = [for s in data.aws_subnet.this : s.arn]
}
  
data "aws_iam_policy_document" "document" {
  statement {
    effect    = "Allow"
    actions   = ["ec2:CreateNetworkInterfacePermission"]
    resources = ["${data.aws_caller_identity.current.arn}:network-interface/*"]
    condition {
      test     = "StringEquals"
      variable = "ec2:Subnet"
      values   = var.subnets
    }
  }
}