Make use of name_prefix optional (#74)

* Make use of name_prefix optional

* Code cleanups, add example

README.md

@@ -198,6 +198,7 @@ Rules and groups are defined in [rules.tf](https://github.com/terraform-aws-modu
 | number_of_computed_ingress_with_source_security_group_id | Number of computed ingress rules to create where 'source_security_group_id' is used | string | `0` | no |
 | rules | Map of known security group rules (define as 'name' = ['from port', 'to port', 'protocol', 'description']) | map | `<map>` | no |
 | tags | A mapping of tags to assign to security group | string | `<map>` | no |
+| use_name_prefix | Whether to use name_prefix or fixed name. Should be true to able to update security group name after initial creation | string | `true` | no |
 | vpc_id | ID of the VPC where to create security group | string | - | yes |
 
 ## Outputs

examples/fixed_name/README.md

+# Complete Security Group example
+
+Configuration in this directory creates set of Security Group and Security Group Rules resources in various combination.
+
+Data sources are used to discover existing VPC resources (VPC and default security group).
+
+## Usage
+
+To run this example you need to execute:
+
+```bash
+$ terraform init
+$ terraform plan
+$ terraform apply
+```
+
+Note that this example may create resources which cost money. Run `terraform destroy` when you don't need these resources.
+
+<!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
+
+## Outputs
+
+| Name | Description |
+|------|-------------|
+| this_security_group_description | The description of the security group |
+| this_security_group_id | The ID of the security group |
+| this_security_group_name | The name of the security group |
+| this_security_group_owner_id | The owner ID |
+| this_security_group_vpc_id | The VPC ID |
+
+<!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->

examples/fixed_name/main.tf

+provider "aws" {
+  region = "eu-west-1"
+}
+
+#############################################################
+# Data sources to get VPC and default security group details
+#############################################################
+data "aws_vpc" "default" {
+  default = true
+}
+
+data "aws_security_group" "default" {
+  name   = "default"
+  vpc_id = "${data.aws_vpc.default.id}"
+}
+
+##################################
+# Security group with a fixed name
+##################################
+module "fixed_name_sg" {
+  source = "../../"
+
+  name            = "fixed-name-sg"
+  description     = "Security group with a fixed name and minimal rules"
+  use_name_prefix = "false"
+  vpc_id          = "${data.aws_vpc.default.id}"
+
+  tags = {
+    Cash       = "king"
+    Department = "kingdom"
+  }
+
+  # Default CIDR blocks, which will be used for all ingress rules in this module. Typically these are CIDR blocks of the VPC.
+  # If this is not specified then no CIDR blocks will be used.
+  ingress_cidr_blocks = ["10.10.0.0/16"]
+
+  # Open for all CIDRs defined in ingress_cidr_blocks
+  ingress_rules = ["https-443-tcp"]
+
+  # Open for self (rule or from_port+to_port+protocol+description)
+  ingress_with_self = [
+    {
+      rule = "all-all"
+    },
+  ]
+
+  # Default CIDR blocks, which will be used for all egress rules in this module. Typically these are CIDR blocks of the VPC.
+  # If this is not specified then no CIDR blocks will be used.
+  egress_cidr_blocks = ["10.10.0.0/16"]
+
+  # Open for self (rule or from_port+to_port+protocol+description)
+  egress_with_self = [
+    {
+      rule = "all-all"
+    },
+  ]
+}

examples/fixed_name/outputs.tf

+output "this_security_group_id" {
+  description = "The ID of the security group"
+  value       = "${module.fixed_name_sg.this_security_group_id}"
+}
+
+output "this_security_group_vpc_id" {
+  description = "The VPC ID"
+  value       = "${module.fixed_name_sg.this_security_group_vpc_id}"
+}
+
+output "this_security_group_owner_id" {
+  description = "The owner ID"
+  value       = "${module.fixed_name_sg.this_security_group_owner_id}"
+}
+
+output "this_security_group_name" {
+  description = "The name of the security group"
+  value       = "${module.fixed_name_sg.this_security_group_name}"
+}
+
+output "this_security_group_description" {
+  description = "The description of the security group"
+  value       = "${module.fixed_name_sg.this_security_group_description}"
+}

outputs.tf

 output "this_security_group_id" {
   description = "The ID of the security group"
-  value       = "${element(concat(aws_security_group.this.*.id, list("")), 0)}"
+  value       = "${element(concat(coalescelist(aws_security_group.this.*.id, aws_security_group.this_name_prefix.*.id), list("")), 0)}"
 }
 
 output "this_security_group_vpc_id" {
   description = "The VPC ID"
-  value       = "${element(concat(aws_security_group.this.*.vpc_id, list("")), 0)}"
+  value       = "${element(concat(coalescelist(aws_security_group.this.*.vpc_id, aws_security_group.this_name_prefix.*.vpc_id), list("")), 0)}"
 }
 
 output "this_security_group_owner_id" {
   description = "The owner ID"
-  value       = "${element(concat(aws_security_group.this.*.owner_id, list("")), 0)}"
+  value       = "${element(concat(coalescelist(aws_security_group.this.*.owner_id, aws_security_group.this_name_prefix.*.owner_id), list("")), 0)}"
 }
 
 output "this_security_group_name" {
   description = "The name of the security group"
-  value       = "${element(concat(aws_security_group.this.*.name, list("")), 0)}"
+  value       = "${element(concat(coalescelist(aws_security_group.this.*.name, aws_security_group.this_name_prefix.*.name), list("")), 0)}"
 }
 
 output "this_security_group_description" {
   description = "The description of the security group"
-  value       = "${element(concat(aws_security_group.this.*.description, list("")), 0)}"
+  value       = "${element(concat(coalescelist(aws_security_group.this.*.description, aws_security_group.this_name_prefix.*.description), list("")), 0)}"
 }
 
 //output "this_security_group_ingress" {

variables.tf

@@ -14,6 +14,11 @@ variable "name" {
   description = "Name of security group"
 }
 
+variable "use_name_prefix" {
+  default     = "true"
+  description = "Whether to use name_prefix or fixed name. Should be true to able to update security group name after initial creation"
+}
+
 variable "description" {
   description = "Description of security group"
   default     = "Security Group managed by Terraform"