this_placement_group change to allow 0 instances.

examples/zero/README.md

@@ -0,0 +1,20 @@
+# Basic EC2 instance
+
+Configuration in this directory creates EC2 instances with minimum set of arguments. It will also assign Elastic IP (EIP) to an instance.
+
+Unspecified arguments for security group id and subnet are inherited from the default VPC.
+
+This example outputs instance id and public DNS name as a single value and as a list.
+
+## 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.
+

examples/zero/main.tf

@@ -0,0 +1,105 @@
+provider "aws" {
+  region = "eu-west-1"
+}
+
+variable "instance_type" {
+  default="t3.large"
+  description="instance type to create / not create"
+}
+
+variable "instance_count" {
+  default=0
+  description="number of instances to create.  test with 0 or 1"
+}
+
+variable "suppress_empty_list" {
+  default=true
+  description="suppress output when 0 instances"
+}
+
+##################################################################
+# Data sources to get VPC, subnet, security group and AMI details
+##################################################################
+data "aws_vpc" "default" {
+  default = true
+}
+
+data "aws_subnet_ids" "all" {
+  vpc_id = data.aws_vpc.default.id
+}
+
+data "aws_ami" "amazon_linux" {
+  most_recent = true
+
+  owners = ["amazon"]
+
+  filter {
+    name = "name"
+
+    values = [
+      "amzn-ami-hvm-*-x86_64-gp2",
+    ]
+  }
+
+  filter {
+    name = "owner-alias"
+
+    values = [
+      "amazon",
+    ]
+  }
+}
+
+module "security_group" {
+  source  = "terraform-aws-modules/security-group/aws"
+  version = "~> 3.0"
+
+  name        = "example"
+  description = "Security group for example usage with EC2 instance"
+  vpc_id      = data.aws_vpc.default.id
+
+  ingress_cidr_blocks = ["0.0.0.0/0"]
+  ingress_rules       = ["http-80-tcp", "all-icmp"]
+  egress_rules        = ["all-all"]
+}
+
+resource "aws_eip" "this" {
+  count    = var.instance_count > 0 ? 1 : 0
+  vpc      = true
+  instance = module.ec2.id[0]
+}
+
+resource "aws_placement_group" "web" {
+  name     = "hunky-dory-pg"
+  strategy = "cluster"
+}
+
+module "ec2" {
+  source = "../../"
+
+  instance_count = var.instance_count
+
+  name          = "example-normal"
+  ami           = data.aws_ami.amazon_linux.id
+  instance_type = var.instance_type
+  subnet_id     = tolist(data.aws_subnet_ids.all.ids)[0]
+  vpc_security_group_ids      = [module.security_group.this_security_group_id]
+  associate_public_ip_address = true
+  placement_group             = aws_placement_group.web.id
+
+  root_block_device = [
+    {
+      volume_type = "gp2"
+      volume_size = 10
+    },
+  ]
+
+  tags = {
+    "Env"      = "Private"
+    "Location" = "Secret"
+  }
+}
+
+
+
+

examples/zero/outputs.tf

@@ -0,0 +1,45 @@
+locals {
+  empty = var.suppress_empty_list && ( length(module.ec2.id) == 0 )
+}
+
+output "ids" {
+  description = "List of IDs of instances"
+  value       = local.empty ? null : module.ec2.id
+}
+
+output "public_dns" {
+  description = "List of public DNS names assigned to the instances"
+  value       = local.empty ? null : module.ec2.public_dns
+}
+
+output "vpc_security_group_ids" {
+  description = "List of VPC security group ids assigned to the instances"
+  value       = local.empty ? null : module.ec2.vpc_security_group_ids
+}
+
+output "tags" {
+  description = "List of tags"
+  value       = local.empty ? null : module.ec2.tags
+}
+
+output "placement_group" {
+  description = "List of placement group"
+  value       = local.empty ? null : module.ec2.placement_group
+}
+
+output "instance_id" {
+  description = "EC2 instance ID"
+  value       = local.empty ? null : module.ec2.id
+}
+
+
+output "instance_public_dns" {
+  description = "Public DNS name assigned to the EC2 instance"
+  value       = local.empty ? null : module.ec2.id
+}
+
+output "credit_specification" {
+  description = "Credit specification of EC2 instance (empty list for not t2 instance types)"
+  value       = local.empty ? null : module.ec2.credit_specification
+}
+

outputs.tf

@@ -7,7 +7,7 @@ locals {
   this_primary_network_interface_id = compact(coalescelist(aws_instance.this.*.primary_network_interface_id, aws_instance.this_t2.*.primary_network_interface_id, [""]))
   this_private_dns                  = compact(coalescelist(aws_instance.this.*.private_dns, aws_instance.this_t2.*.private_dns, [""]))
   this_private_ip                   = compact(coalescelist(aws_instance.this.*.private_ip, aws_instance.this_t2.*.private_ip, [""]))
-  this_placement_group              = compact(concat(coalescelist(aws_instance.this.*.placement_group, aws_instance.this_t2.*.placement_group), [""]))
+  this_placement_group              = compact(coalescelist(aws_instance.this.*.placement_group, aws_instance.this_t2.*.placement_group, [""]))
   this_security_groups              = coalescelist(aws_instance.this.*.security_groups, aws_instance.this_t2.*.security_groups, [""])
   this_vpc_security_group_ids       = coalescelist(flatten(aws_instance.this.*.vpc_security_group_ids), flatten(aws_instance.this_t2.*.vpc_security_group_ids), [""])
   this_subnet_id                    = compact(coalescelist(aws_instance.this.*.subnet_id, aws_instance.this_t2.*.subnet_id, [""]))