fix: Setting var.launch_template doesn't work due to default ami and instance_type vars

examples/launch-template/README.md

@@ -0,0 +1,78 @@
+# EC2 instance with Launch template
+
+Configuration in this directory creates EC2 instances with different sets of arguments (with Elastic IP, with network interface attached, with credit specifications).
+
+## Usage
+
+To run this example you need to execute:
+
+```bash
+$ terraform init
+$ terraform plan
+$ terraform apply
+```
+
+Note that this example may create resources which can cost money. Run `terraform destroy` when you don't need these resources.
+
+<!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
+## Requirements
+
+| Name | Version |
+|------|---------|
+| <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 1.0 |
+| <a name="requirement_aws"></a> [aws](#requirement\_aws) | >= 4.66 |
+| <a name="requirement_tls"></a> [tls](#requirement\_tls) | >= 4.0.5 |
+
+## Providers
+
+| Name | Version |
+|------|---------|
+| <a name="provider_aws"></a> [aws](#provider\_aws) | >= 4.66 |
+| <a name="provider_tls"></a> [tls](#provider\_tls) | >= 4.0.5 |
+
+## Modules
+
+| Name | Source | Version |
+|------|--------|---------|
+| <a name="module_ec2_from_launch_template"></a> [ec2\_from\_launch\_template](#module\_ec2\_from\_launch\_template) | ../../ | n/a |
+| <a name="module_security_group"></a> [security\_group](#module\_security\_group) | terraform-aws-modules/security-group/aws | ~> 4.0 |
+| <a name="module_vpc"></a> [vpc](#module\_vpc) | terraform-aws-modules/vpc/aws | ~> 5.0 |
+
+## Resources
+
+| Name | Type |
+|------|------|
+| [aws_key_pair.tf_key](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/key_pair) | resource |
+| [aws_launch_template.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/launch_template) | resource |
+| [tls_private_key.ed25519](https://registry.terraform.io/providers/hashicorp/tls/latest/docs/resources/private_key) | resource |
+| [aws_ami.amazon_linux_23](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/ami) | data source |
+| [aws_availability_zones.available](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/availability_zones) | data source |
+
+## Inputs
+
+No inputs.
+
+## Outputs
+
+| Name | Description |
+|------|-------------|
+| <a name="output_ec2_arn"></a> [ec2\_arn](#output\_ec2\_arn) | The ARN of the instance |
+| <a name="output_ec2_availability_zone"></a> [ec2\_availability\_zone](#output\_ec2\_availability\_zone) | The availability zone of the created instance |
+| <a name="output_ec2_capacity_reservation_specification"></a> [ec2\_capacity\_reservation\_specification](#output\_ec2\_capacity\_reservation\_specification) | Capacity reservation specification of the instance |
+| <a name="output_ec2_ebs_block_device"></a> [ec2\_ebs\_block\_device](#output\_ec2\_ebs\_block\_device) | EBS block device information |
+| <a name="output_ec2_ephemeral_block_device"></a> [ec2\_ephemeral\_block\_device](#output\_ec2\_ephemeral\_block\_device) | Ephemeral block device information |
+| <a name="output_ec2_iam_instance_profile_arn"></a> [ec2\_iam\_instance\_profile\_arn](#output\_ec2\_iam\_instance\_profile\_arn) | ARN assigned by AWS to the instance profile |
+| <a name="output_ec2_iam_instance_profile_id"></a> [ec2\_iam\_instance\_profile\_id](#output\_ec2\_iam\_instance\_profile\_id) | Instance profile's ID |
+| <a name="output_ec2_iam_instance_profile_unique"></a> [ec2\_iam\_instance\_profile\_unique](#output\_ec2\_iam\_instance\_profile\_unique) | Stable and unique string identifying the IAM instance profile |
+| <a name="output_ec2_iam_role_arn"></a> [ec2\_iam\_role\_arn](#output\_ec2\_iam\_role\_arn) | The Amazon Resource Name (ARN) specifying the IAM role |
+| <a name="output_ec2_iam_role_name"></a> [ec2\_iam\_role\_name](#output\_ec2\_iam\_role\_name) | The name of the IAM role |
+| <a name="output_ec2_iam_role_unique_id"></a> [ec2\_iam\_role\_unique\_id](#output\_ec2\_iam\_role\_unique\_id) | Stable and unique string identifying the IAM role |
+| <a name="output_ec2_id"></a> [ec2\_id](#output\_ec2\_id) | The ID of the instance |
+| <a name="output_ec2_instance_state"></a> [ec2\_instance\_state](#output\_ec2\_instance\_state) | The state of the instance. One of: `pending`, `running`, `shutting-down`, `terminated`, `stopping`, `stopped` |
+| <a name="output_ec2_primary_network_interface_id"></a> [ec2\_primary\_network\_interface\_id](#output\_ec2\_primary\_network\_interface\_id) | The ID of the instance's primary network interface |
+| <a name="output_ec2_private_dns"></a> [ec2\_private\_dns](#output\_ec2\_private\_dns) | The private DNS name assigned to the instance. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC |
+| <a name="output_ec2_public_dns"></a> [ec2\_public\_dns](#output\_ec2\_public\_dns) | The public DNS name assigned to the instance. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC |
+| <a name="output_ec2_public_ip"></a> [ec2\_public\_ip](#output\_ec2\_public\_ip) | The public IP address assigned to the instance, if applicable. NOTE: If you are using an aws\_eip with your instance, you should refer to the EIP's address directly and not use `public_ip` as this field will change after the EIP is attached |
+| <a name="output_ec2_root_block_device"></a> [ec2\_root\_block\_device](#output\_ec2\_root\_block\_device) | Root block device information |
+| <a name="output_ec2_tags_all"></a> [ec2\_tags\_all](#output\_ec2\_tags\_all) | A map of tags assigned to the resource, including those inherited from the provider default\_tags configuration block |
+<!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->

examples/launch-template/main.tf

@@ -0,0 +1,109 @@
+provider "aws" {
+  region = local.region
+}
+
+data "aws_availability_zones" "available" {}
+
+locals {
+  name   = "ex-${basename(path.cwd)}"
+  region = "eu-west-1"
+
+  vpc_cidr = "10.0.0.0/16"
+  azs      = slice(data.aws_availability_zones.available.names, 0, 3)
+
+  user_data = <<-EOT
+    #!/bin/bash
+    echo "Hello Terraform!"
+  EOT
+
+  tags = {
+    Name       = local.name
+    Example    = local.name
+    Repository = "https://github.com/terraform-aws-modules/terraform-aws-ec2-instance"
+  }
+}
+
+################################################################################
+# EC2 Module
+################################################################################
+
+module "ec2_from_launch_template" {
+  source = "../../"
+
+  name = local.name
+
+  launch_template = {
+    id = aws_launch_template.this.id
+  }
+
+  tags = local.tags
+}
+
+################################################################################
+# Supporting Resources
+################################################################################
+
+module "vpc" {
+  source  = "terraform-aws-modules/vpc/aws"
+  version = "~> 5.0"
+
+  name = local.name
+  cidr = local.vpc_cidr
+
+  azs             = local.azs
+  private_subnets = [for k, v in local.azs : cidrsubnet(local.vpc_cidr, 4, k)]
+  public_subnets  = [for k, v in local.azs : cidrsubnet(local.vpc_cidr, 8, k + 48)]
+
+  tags = local.tags
+}
+
+data "aws_ami" "amazon_linux_23" {
+  most_recent = true
+  owners      = ["amazon"]
+
+  filter {
+    name   = "name"
+    values = ["al2023-ami-2023*-x86_64"]
+  }
+}
+
+module "security_group" {
+  source  = "terraform-aws-modules/security-group/aws"
+  version = "~> 4.0"
+
+  name        = local.name
+  description = "Security group for example usage with EC2 instance"
+  vpc_id      = module.vpc.vpc_id
+
+  ingress_cidr_blocks = ["0.0.0.0/0"]
+  ingress_rules       = ["http-80-tcp", "all-icmp"]
+  egress_rules        = ["all-all"]
+
+  tags = local.tags
+}
+
+resource "tls_private_key" "ed25519" {
+  algorithm = "ED25519"
+}
+
+resource "aws_key_pair" "tf_key" {
+  key_name   = "terraform-ec2-instances-example"
+  public_key = tls_private_key.ed25519.public_key_openssh
+}
+
+resource "aws_launch_template" "this" {
+  image_id      = data.aws_ami.amazon_linux_23.id
+  instance_type = "c5.large"
+  key_name      = aws_key_pair.tf_key.key_name
+  user_data     = local.user_data
+
+  network_interfaces {
+    security_groups = [module.security_group.security_group_id]
+    subnet_id       = module.vpc.private_subnets[0]
+  }
+
+  tag_specifications {
+    resource_type = "instance"
+    tags          = local.tags
+  }
+}

examples/launch-template/outputs.tf

@@ -0,0 +1,94 @@
+output "ec2_id" {
+  description = "The ID of the instance"
+  value       = module.ec2_from_launch_template.id
+}
+
+output "ec2_arn" {
+  description = "The ARN of the instance"
+  value       = module.ec2_from_launch_template.arn
+}
+
+output "ec2_capacity_reservation_specification" {
+  description = "Capacity reservation specification of the instance"
+  value       = module.ec2_from_launch_template.capacity_reservation_specification
+}
+
+output "ec2_instance_state" {
+  description = "The state of the instance. One of: `pending`, `running`, `shutting-down`, `terminated`, `stopping`, `stopped`"
+  value       = module.ec2_from_launch_template.instance_state
+}
+
+output "ec2_primary_network_interface_id" {
+  description = "The ID of the instance's primary network interface"
+  value       = module.ec2_from_launch_template.primary_network_interface_id
+}
+
+output "ec2_private_dns" {
+  description = "The private DNS name assigned to the instance. Can only be used inside the Amazon EC2, and only available if you've enabled DNS hostnames for your VPC"
+  value       = module.ec2_from_launch_template.private_dns
+}
+
+output "ec2_public_dns" {
+  description = "The public DNS name assigned to the instance. For EC2-VPC, this is only available if you've enabled DNS hostnames for your VPC"
+  value       = module.ec2_from_launch_template.public_dns
+}
+
+output "ec2_public_ip" {
+  description = "The public IP address assigned to the instance, if applicable. NOTE: If you are using an aws_eip with your instance, you should refer to the EIP's address directly and not use `public_ip` as this field will change after the EIP is attached"
+  value       = module.ec2_from_launch_template.public_ip
+}
+
+output "ec2_tags_all" {
+  description = "A map of tags assigned to the resource, including those inherited from the provider default_tags configuration block"
+  value       = module.ec2_from_launch_template.tags_all
+}
+
+output "ec2_iam_role_name" {
+  description = "The name of the IAM role"
+  value       = module.ec2_from_launch_template.iam_role_name
+}
+
+output "ec2_iam_role_arn" {
+  description = "The Amazon Resource Name (ARN) specifying the IAM role"
+  value       = module.ec2_from_launch_template.iam_role_arn
+}
+
+output "ec2_iam_role_unique_id" {
+  description = "Stable and unique string identifying the IAM role"
+  value       = module.ec2_from_launch_template.iam_role_unique_id
+}
+
+output "ec2_iam_instance_profile_arn" {
+  description = "ARN assigned by AWS to the instance profile"
+  value       = module.ec2_from_launch_template.iam_instance_profile_arn
+}
+
+output "ec2_iam_instance_profile_id" {
+  description = "Instance profile's ID"
+  value       = module.ec2_from_launch_template.iam_instance_profile_id
+}
+
+output "ec2_iam_instance_profile_unique" {
+  description = "Stable and unique string identifying the IAM instance profile"
+  value       = module.ec2_from_launch_template.iam_instance_profile_unique
+}
+
+output "ec2_root_block_device" {
+  description = "Root block device information"
+  value       = module.ec2_from_launch_template.root_block_device
+}
+
+output "ec2_ebs_block_device" {
+  description = "EBS block device information"
+  value       = module.ec2_from_launch_template.ebs_block_device
+}
+
+output "ec2_ephemeral_block_device" {
+  description = "Ephemeral block device information"
+  value       = module.ec2_from_launch_template.ephemeral_block_device
+}
+
+output "ec2_availability_zone" {
+  description = "The availability zone of the created instance"
+  value       = module.ec2_from_launch_template.availability_zone
+}

examples/launch-template/versions.tf

@@ -0,0 +1,14 @@
+terraform {
+  required_version = ">= 1.0"
+
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = ">= 4.66"
+    }
+    tls = {
+      source  = "hashicorp/tls"
+      version = ">= 4.0.5"
+    }
+  }
+}

main.tf

@@ -21,8 +21,8 @@ data "aws_ssm_parameter" "this" {
 resource "aws_instance" "this" {
   count = local.create && !var.ignore_ami_changes && !var.create_spot_instance ? 1 : 0
 
-  ami                  = local.ami
-  instance_type        = var.instance_type
+  ami                  = length(var.launch_template) == 0 ? local.ami : null
+  instance_type        = length(var.launch_template) == 0 ? var.instance_type : null
   cpu_core_count       = var.cpu_core_count
   cpu_threads_per_core = var.cpu_threads_per_core
   hibernation          = var.hibernation
@@ -199,8 +199,8 @@ resource "aws_instance" "this" {
 resource "aws_instance" "ignore_ami" {
   count = local.create && var.ignore_ami_changes && !var.create_spot_instance ? 1 : 0
 
-  ami                  = local.ami
-  instance_type        = var.instance_type
+  ami                  = length(var.launch_template) == 0 ? local.ami : null
+  instance_type        = length(var.launch_template) == 0 ? var.instance_type : null
   cpu_core_count       = var.cpu_core_count
   cpu_threads_per_core = var.cpu_threads_per_core
   hibernation          = var.hibernation
@@ -383,8 +383,8 @@ resource "aws_instance" "ignore_ami" {
 resource "aws_spot_instance_request" "this" {
   count = local.create && var.create_spot_instance ? 1 : 0
 
-  ami                  = local.ami
-  instance_type        = var.instance_type
+  ami                  = length(var.launch_template) == 0 ? local.ami : null
+  instance_type        = length(var.launch_template) == 0 ? var.instance_type : null
   cpu_core_count       = var.cpu_core_count
   cpu_threads_per_core = var.cpu_threads_per_core
   hibernation          = var.hibernation