Enable terraform plan access via dynamic Terraform roles (cloudposse/terraform-aws-components#715)

Author: Nuru

src/README.md

@@ -95,9 +95,7 @@ components:
 
 | Name | Type |
 |------|------|
-| [aws_eks_cluster.kubernetes](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/eks_cluster) | data source |
 | [aws_eks_cluster_auth.eks](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/eks_cluster_auth) | data source |
-| [aws_eks_cluster_auth.kubernetes](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/eks_cluster_auth) | data source |
 
 ## Inputs
 
@@ -121,8 +119,6 @@ components:
 | <a name="input_helm_manifest_experiment_enabled"></a> [helm\_manifest\_experiment\_enabled](#input\_helm\_manifest\_experiment\_enabled) | Enable storing of the rendered manifest for helm\_release so the full diff of what is changing can been seen in the plan | `bool` | `false` | no |
 | <a name="input_hostname_template"></a> [hostname\_template](#input\_hostname\_template) | The `format()` string to use to generate the hostname via `format(var.hostname_template, var.tenant, var.stage, var.environment)`"<br>Typically something like `"echo.%[3]v.%[2]v.example.com"`. | `string` | n/a | yes |
 | <a name="input_id_length_limit"></a> [id\_length\_limit](#input\_id\_length\_limit) | Limit `id` to this many characters (minimum 6).<br>Set to `0` for unlimited length.<br>Set to `null` for keep the existing setting, which defaults to `0`.<br>Does not affect `id_full`. | `number` | `null` | no |
-| <a name="input_import_profile_name"></a> [import\_profile\_name](#input\_import\_profile\_name) | AWS Profile name to use when importing a resource | `string` | `null` | no |
-| <a name="input_import_role_arn"></a> [import\_role\_arn](#input\_import\_role\_arn) | IAM Role ARN to use when importing a resource | `string` | `null` | no |
 | <a name="input_ingress_type"></a> [ingress\_type](#input\_ingress\_type) | Set to 'nginx' to create an ingress resource relying on an NGiNX backend for the echo-server service. Set to 'alb' to create an ingress resource relying on an AWS ALB backend for the echo-server service. Leave blank to not create any ingress for the echo-server service. | `string` | `null` | no |
 | <a name="input_kube_data_auth_enabled"></a> [kube\_data\_auth\_enabled](#input\_kube\_data\_auth\_enabled) | If `true`, use an `aws_eks_cluster_auth` data source to authenticate to the EKS cluster.<br>Disabled by `kubeconfig_file_enabled` or `kube_exec_auth_enabled`. | `bool` | `false` | no |
 | <a name="input_kube_exec_auth_aws_profile"></a> [kube\_exec\_auth\_aws\_profile](#input\_kube\_exec\_auth\_aws\_profile) | The AWS config profile for `aws eks get-token` to use | `string` | `""` | no |

src/provider-helm.tf

@@ -2,6 +2,12 @@
 #
 # This file is a drop-in to provide a helm provider.
 #
+# It depends on 2 standard Cloud Posse data source modules to be already
+# defined in the same component:
+#
+#   1. module.iam_roles to provide the AWS profile or Role ARN to use to access the cluster
+#   2. module.eks to provide the EKS cluster information
+#
 # All the following variables are just about configuring the Kubernetes provider
 # to be able to modify EKS cluster. The reason there are so many options is
 # because at various times, each one of them has had problems, so we give you a choice.
@@ -95,14 +101,16 @@ locals {
     "--profile", var.kube_exec_auth_aws_profile
   ] : []
 
-  kube_exec_auth_role_arn = coalesce(var.kube_exec_auth_role_arn, var.import_role_arn, module.iam_roles.terraform_role_arn)
+  kube_exec_auth_role_arn = coalesce(var.kube_exec_auth_role_arn, module.iam_roles.terraform_role_arn)
   exec_role = local.kube_exec_auth_enabled && var.kube_exec_auth_role_arn_enabled ? [
     "--role-arn", local.kube_exec_auth_role_arn
   ] : []
 
-  certificate_authority_data = module.eks.outputs.eks_cluster_certificate_authority_data
-  eks_cluster_id             = module.eks.outputs.eks_cluster_id
-  eks_cluster_endpoint       = module.eks.outputs.eks_cluster_endpoint
+  # Provide dummy configuration for the case where the EKS cluster is not available.
+  certificate_authority_data = try(module.eks.outputs.eks_cluster_certificate_authority_data, "")
+  # Use coalesce+try to handle both the case where the output is missing and the case where it is empty.
+  eks_cluster_id       = coalesce(try(module.eks.outputs.eks_cluster_id, ""), "missing")
+  eks_cluster_endpoint = try(module.eks.outputs.eks_cluster_endpoint, "")
 }
 
 data "aws_eks_cluster_auth" "eks" {
@@ -114,14 +122,14 @@ provider "helm" {
   kubernetes {
     host                   = local.eks_cluster_endpoint
     cluster_ca_certificate = base64decode(local.certificate_authority_data)
-    token                  = local.kube_data_auth_enabled ? data.aws_eks_cluster_auth.eks[0].token : null
+    token                  = local.kube_data_auth_enabled ? one(data.aws_eks_cluster_auth.eks[*].token) : null
     # The Kubernetes provider will use information from KUBECONFIG if it exists, but if the default cluster
     # in KUBECONFIG is some other cluster, this will cause problems, so we override it always.
     config_path    = local.kubeconfig_file_enabled ? var.kubeconfig_file : ""
     config_context = var.kubeconfig_context
 
     dynamic "exec" {
-      for_each = local.kube_exec_auth_enabled ? ["exec"] : []
+      for_each = local.kube_exec_auth_enabled && length(local.certificate_authority_data) > 0 ? ["exec"] : []
       content {
         api_version = local.kubeconfig_exec_auth_api_version
         command     = "aws"
@@ -132,21 +140,21 @@ provider "helm" {
     }
   }
   experiments {
-    manifest = var.helm_manifest_experiment_enabled
+    manifest = var.helm_manifest_experiment_enabled && module.this.enabled
   }
 }
 
 provider "kubernetes" {
   host                   = local.eks_cluster_endpoint
   cluster_ca_certificate = base64decode(local.certificate_authority_data)
-  token                  = local.kube_data_auth_enabled ? data.aws_eks_cluster_auth.eks[0].token : null
+  token                  = local.kube_data_auth_enabled ? one(data.aws_eks_cluster_auth.eks[*].token) : null
   # The Kubernetes provider will use information from KUBECONFIG if it exists, but if the default cluster
   # in KUBECONFIG is some other cluster, this will cause problems, so we override it always.
   config_path    = local.kubeconfig_file_enabled ? var.kubeconfig_file : ""
   config_context = var.kubeconfig_context
 
   dynamic "exec" {
-    for_each = local.kube_exec_auth_enabled ? ["exec"] : []
+    for_each = local.kube_exec_auth_enabled && length(local.certificate_authority_data) > 0 ? ["exec"] : []
     content {
       api_version = local.kubeconfig_exec_auth_api_version
       command     = "aws"

src/providers.tf

@@ -1,11 +1,14 @@
 provider "aws" {
   region = var.region
 
-  profile = module.iam_roles.profiles_enabled ? coalesce(var.import_profile_name, module.iam_roles.terraform_profile_name) : null
+  # Profile is deprecated in favor of terraform_role_arn. When profiles are not in use, terraform_profile_name is null.
+  profile = module.iam_roles.terraform_profile_name
+
   dynamic "assume_role" {
-    for_each = module.iam_roles.profiles_enabled ? [] : ["role"]
+    # module.iam_roles.terraform_role_arn may be null, in which case do not assume a role.
+    for_each = compact([module.iam_roles.terraform_role_arn])
     content {
-      role_arn = coalesce(var.import_role_arn, module.iam_roles.terraform_role_arn)
+      role_arn = module.iam_roles.terraform_role_arn
     }
   }
 }
@@ -14,27 +17,3 @@ module "iam_roles" {
   source  = "../../account-map/modules/iam-roles"
   context = module.this.context
 }
-
-variable "import_profile_name" {
-  type        = string
-  default     = null
-  description = "AWS Profile name to use when importing a resource"
-}
-
-variable "import_role_arn" {
-  type        = string
-  default     = null
-  description = "IAM Role ARN to use when importing a resource"
-}
-
-data "aws_eks_cluster" "kubernetes" {
-  count = local.enabled ? 1 : 0
-
-  name = module.eks.outputs.eks_cluster_id
-}
-
-data "aws_eks_cluster_auth" "kubernetes" {
-  count = local.enabled ? 1 : 0
-
-  name = module.eks.outputs.eks_cluster_id
-}