feat: bind existing aws policy to role

README.md

@@ -1,6 +1,8 @@
 # Terraform Module: IAM Role
 
-This is a Terraform module for creating custom AWS IAM roles.
+This is DAQ's Terraform Module for AWS IAM role management.
+
+This repo provides a template for other Terraform repos to create IAM roles.
 
 ## Install
 
@@ -11,7 +13,11 @@ This is a Terraform module for creating custom AWS IAM roles.
 ## Usage
 
 This module creates an IAM Role and its policy document.
-You need to pass your custom policy document to the module.
+You need to pass your custom policy document or a list of AWS pre-defined policies to the module.
+
+## Example
+
+See [examples](./examples/).
 
 <!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
 ## Requirements
@@ -35,8 +41,9 @@ No modules.
 | Name | Type |
 |------|------|
 | [aws_iam_policy.custom_policy](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_policy) | resource |
-| [aws_iam_policy_attachment.custom_attachment](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_policy_attachment) | resource |
+| [aws_iam_policy_attachment.custom_policy_attachment](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_policy_attachment) | resource |
 | [aws_iam_role.custom_role](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role) | resource |
+| [aws_iam_role_policy_attachment.existing_policy_attachment](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role_policy_attachment) | resource |
 | [aws_caller_identity.current](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/caller_identity) | data source |
 | [aws_iam_policy_document.assume_role](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/iam_policy_document) | data source |
 
@@ -45,6 +52,7 @@ No modules.
 | Name | Description | Type | Default | Required |
 |------|-------------|------|---------|:--------:|
 | <a name="input_arns_assume_role"></a> [arns\_assume\_role](#input\_arns\_assume\_role) | List of ARNs of IAM entities that can assume the role | `list(string)` | `[]` | no |
+| <a name="input_existing_iam_policy_arns"></a> [existing\_iam\_policy\_arns](#input\_existing\_iam\_policy\_arns) | List of ARNs of existing IAM policies | `list(string)` | `[]` | no |
 | <a name="input_iam_policy_document"></a> [iam\_policy\_document](#input\_iam\_policy\_document) | Custom IAM policy document | `string` | `""` | no |
 | <a name="input_name_prefix"></a> [name\_prefix](#input\_name\_prefix) | Name prefix for IAM role name | `string` | `""` | no |
 | <a name="input_role_description"></a> [role\_description](#input\_role\_description) | An optional IAM role description | `string` | `""` | no |

examples/deployer_roles/README.md

@@ -0,0 +1,33 @@
+# deployer_roles
+
+<!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
+## Requirements
+
+No requirements.
+
+## Providers
+
+| Name | Version |
+|------|---------|
+| <a name="provider_aws"></a> [aws](#provider\_aws) | n/a |
+
+## Modules
+
+| Name | Source | Version |
+|------|--------|---------|
+| <a name="module_devops_infra_deploy"></a> [devops\_infra\_deploy](#module\_devops\_infra\_deploy) | ../.. | n/a |
+
+## Resources
+
+| Name | Type |
+|------|------|
+| [aws_iam_policy_document.ecs_infra_role_policy](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/iam_policy_document) | data source |
+
+## Inputs
+
+No inputs.
+
+## Outputs
+
+No outputs.
+<!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->

examples/deployer_roles/ecs_deployer.tf

@@ -0,0 +1,49 @@
+data "aws_iam_policy_document" "ecs_infra_role_policy" {
+  statement {
+    resources = ["arn:aws:s3:::ecs-infrastructre"]
+    actions = [
+      "s3:ListBucket",
+    ]
+  }
+
+  statement {
+    resources = ["arn:aws:s3:::ecs-infrastructre/*"]
+    actions = [
+      "s3:Get*",
+      "s3:Put*",
+      "s3:Delete*",
+    ]
+  }
+
+  statement {
+    resources = ["arn:aws:iam::000000000000:role/service_roles/*"]
+    actions   = ["iam:PassRole"]
+  }
+
+  // enable VPCs, subnets, route tables and internet gateways creation
+  statement {
+    resources = ["*"]
+    actions = [
+      "ec2:Describe*",
+      "ec2:Create*",
+      "ec2:Delete*",
+      "ec2:AttachInternetGateway",
+      "ec2:AssociateRouteTable",
+      "ec2:ModifyVpcAttribute",
+      "ec2:DisableVpcClassicLink",
+      "ec2:DisableVpcClassicLinkDnsSupport",
+      "ec2:EnableVpcClassicLink",
+      "ec2:EnableVpcClassicLinkDnsSupport",
+    ]
+  }
+}
+
+module "devops_infra_deploy" {
+  source = "../.."
+
+  name_prefix         = "ecsInfraDeploy"
+  role_path           = "/ecs/"
+  role_description    = "Role for deploying ECS infrastructure"
+  iam_policy_document = data.aws_iam_policy_document.ecs_infra_role_policy.json
+  arns_assume_role    = ["arn:aws:iam::000000000000:root"]
+}

examples/human_roles/README.md

@@ -0,0 +1,29 @@
+# human_roles
+
+<!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
+## Requirements
+
+No requirements.
+
+## Providers
+
+No providers.
+
+## Modules
+
+| Name | Source | Version |
+|------|--------|---------|
+| <a name="module_amplify_and_cognito_admin"></a> [amplify\_and\_cognito\_admin](#module\_amplify\_and\_cognito\_admin) | ../.. | n/a |
+
+## Resources
+
+No resources.
+
+## Inputs
+
+No inputs.
+
+## Outputs
+
+No outputs.
+<!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->

examples/human_roles/amplify_admin.tf

@@ -0,0 +1,9 @@
+module "amplify_and_cognito_admin" {
+  source = "../.."
+
+  name_prefix              = "amplifyAdmin"
+  role_path                = "/human/"
+  role_description         = "Role for granting admin access on Amplify"
+  existing_iam_policy_arns = ["arn:aws:iam::aws:policy/AdministratorAccess-Amplify"]
+  arns_assume_role         = ["arn:aws:iam::000000000000:root"]
+}

examples/service_roles/README.md

@@ -0,0 +1,33 @@
+# service_roles
+
+<!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
+## Requirements
+
+No requirements.
+
+## Providers
+
+| Name | Version |
+|------|---------|
+| <a name="provider_aws"></a> [aws](#provider\_aws) | n/a |
+
+## Modules
+
+| Name | Source | Version |
+|------|--------|---------|
+| <a name="module_lambda_auto_link_data_iam_role"></a> [lambda\_auto\_link\_data\_iam\_role](#module\_lambda\_auto\_link\_data\_iam\_role) | ../.. | n/a |
+
+## Resources
+
+| Name | Type |
+|------|------|
+| [aws_iam_policy_document.lambda_policy](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/iam_policy_document) | data source |
+
+## Inputs
+
+No inputs.
+
+## Outputs
+
+No outputs.
+<!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->

examples/service_roles/lambda_service_roles.tf

@@ -0,0 +1,20 @@
+data "aws_iam_policy_document" "lambda_policy" {
+  statement {
+    actions = [
+      "logs:CreateLogStream",
+      "logs:PutLogEvents",
+    ]
+
+    resources = ["*"]
+  }
+}
+
+module "lambda_auto_link_data_iam_role" {
+  source = "../.."
+
+  name_prefix          = "myLambda"
+  role_path            = "/service_roles/"
+  role_description     = "Allows resources to log to log groups"
+  iam_policy_document  = data.aws_iam_policy_document.lambda_policy.json
+  services_assume_role = ["lambda.amazonaws.com"]
+}

main.tf

@@ -8,14 +8,28 @@ resource "aws_iam_role" "custom_role" {
 }
 
 resource "aws_iam_policy" "custom_policy" {
+  for_each = var.iam_policy_document == "" ? {} : { "policy" : true }
+
   name   = "${var.name_prefix}Policy"
   path   = "/"
   policy = var.iam_policy_document
 }
 
-resource "aws_iam_policy_attachment" "custom_attachment" {
+resource "aws_iam_policy_attachment" "custom_policy_attachment" {
+  for_each = var.iam_policy_document == "" ? {} : { "attachment" : true }
+
   name       = "${var.name_prefix}Attachment"
   roles      = [aws_iam_role.custom_role.name]
-  policy_arn = aws_iam_policy.custom_policy.arn
+  policy_arn = aws_iam_policy.custom_policy["policy"].arn
+
   depends_on = [aws_iam_role.custom_role, aws_iam_policy.custom_policy]
 }
+
+resource "aws_iam_role_policy_attachment" "existing_policy_attachment" {
+  for_each = var.existing_iam_policy_arns == [] ? toset([]) : toset(var.existing_iam_policy_arns)
+
+  role       = aws_iam_role.custom_role.name
+  policy_arn = each.key
+
+  depends_on = [aws_iam_role.custom_role]
+}

variables.tf

@@ -1,35 +1,41 @@
 variable "name_prefix" {
-  default     = ""
-  description = "Name prefix for IAM role name"
   type        = string
+  description = "Name prefix for IAM role name"
+  default     = ""
 }
 
 variable "role_path" {
-  default     = ""
-  description = "An optional IAM role path"
   type        = string
+  description = "An optional IAM role path"
+  default     = ""
 }
 
 variable "role_description" {
-  default     = ""
-  description = "An optional IAM role description"
   type        = string
+  description = "An optional IAM role description"
+  default     = ""
 }
 
 variable "iam_policy_document" {
-  default     = ""
-  description = "Custom IAM policy document"
   type        = string
+  description = "Custom IAM policy document"
+  default     = ""
 }
 
-variable "arns_assume_role" {
+variable "existing_iam_policy_arns" {
+  type        = list(string)
+  description = "List of ARNs of existing IAM policies"
   default     = []
+}
+
+variable "arns_assume_role" {
   type        = list(string)
   description = "List of ARNs of IAM entities that can assume the role"
+  default     = []
 }
 
 variable "services_assume_role" {
-  default     = []
   type        = list(string)
   description = "List of services that can assume the role"
+  default     = []
 }