Retrieve per-AZ autoscaling group names from managed node groups when using the AWS EKS terraform module

asg-names.tf

variable "availability_zones" {
  type        = map(string)
  description = "Availability zones to use, mapped to networks to assign"
  default = {
    "us-east-1a" : "172.16.0.0/18",
    "us-east-1b" : "172.16.64.0/18",
  }
}

locals {
  /*
  ### autoscaling_groups is parsed from an object like this in module.eks.node_groups
  node_groups = {
    "group-a" = {
      "resources" = tolist([
        {
          "autoscaling_groups" = tolist([
            {
              "name" = "eks-use2-dev-1-group-a202201111845031276500000023-52bf253a-9cae-fae8-111d-867d7d3bc695"
            },
          ])
          "remote_access_security_group_id" = ""
        },
      ])
    }
    "group-b" = {
      "resources" = tolist([
        {
          "autoscaling_groups" = tolist([
            {
              "name" = "eks-use2-dev-1-group-b2022011118450321830000002b-70bf253a-9cdb-1bf0-4270-32f4d47b4628"
            },
          ])
          "remote_access_security_group_id" = ""
        },
      ])
    }
  }
  */
  autoscaling_groups = {
    for az in keys(var.availability_zones) : az =>
    [for asg in flatten(
      [for item in module.eks.node_groups["group-${substr(az, -1, 1)}"]["resources"] : item["autoscaling_groups"]
      if lookup(item, "autoscaling_groups", false) != false]
    ) : asg["name"]]
  }
}