terraform-module-library

name terraform-module-library description Build reusable Terraform modules for AWS, Azure, GCP, and OCI infrastructure following infrastructure-as-code best practices. Use when creating infrastructure modules, standardizing cloud provisioning, or implementing reusable IaC components. Terraform Module Library Production-ready Terraform module patterns for AWS, Azure, GCP, and OCI infrastructure. Purpose Create reusable, well-tested Terraform modules for common cloud infrastructure patterns across multiple cloud providers. When to Use Build reusable infrastructure components Standardize cloud resource provisioning Implement infrastructure as code best practices Create multi-cloud compatible modules Establish organizational Terraform standards Module Structure terraform-modules/ ├── aws/ │ ├── vpc/ │ ├── eks/ │ ├── rds/ │ └── s3/ ├── azure/ │ ├── vnet/ │ ├── aks/ │ └── storage/ ├── gcp/ │ ├── vpc/ │ ├── gke/ │ └── cloud-sql/ └── oci/ ├── vcn/ ├── oke/ └── object-storage/ Standard Module Pattern module-name/ ├── main.tf # Main resources ├── variables.tf # Input variables ├── outputs.tf # Output values ├── versions.tf # Provider versions ├── README.md # Documentation ├── examples/ # Usage examples │ └── complete/ │ ├── main.tf │ └── variables.tf └── tests/ # Terratest files └── module_test.go AWS VPC Module Example main.tf: resource "aws_vpc" "main" { cidr_block = var.cidr_block enable_dns_hostnames = var.enable_dns_hostnames enable_dns_support = var.enable_dns_support tags = merge( { Name = var.name }, var.tags ) } resource "aws_subnet" "private" { count = length(var.private_subnet_cidrs) vpc_id = aws_vpc.main.id cidr_block = var.private_subnet_cidrs[count.index] availability_zone = var.availability_zones[count.index] tags = merge( { Name = "${var.name}-private-${count.index + 1}" Tier = "private" }, var.tags ) } resource "aws_internet_gateway" "main" { count = var.create_internet_gateway ? 1 : 0 vpc_id = aws_vpc.main.id tags = merge( { Name = "${var.name}-igw" }, var.tags ) } variables.tf: variable "name" { description = "Name of the VPC" type = string } variable "cidr_block" { description = "CIDR block for VPC" type = string validation { condition = can(regex("^([0-9]{1,3}\\.){3}[0-9]{1,3}/[0-9]{1,2}$", var.cidr_block)) error_message = "CIDR block must be valid IPv4 CIDR notation." } } variable "availability_zones" { description = "List of availability zones" type = list(string) } variable "private_subnet_cidrs" { description = "CIDR blocks for private subnets" type = list(string) default = [] } variable "enable_dns_hostnames" { description = "Enable DNS hostnames in VPC" type = bool default = true } variable "tags" { description = "Additional tags" type = map(string) default = {} } outputs.tf: output "vpc_id" { description = "ID of the VPC" value = aws_vpc.main.id } output "private_subnet_ids" { description = "IDs of private subnets" value = aws_subnet.private[*].id } output "vpc_cidr_block" { description = "CIDR block of VPC" value = aws_vpc.main.cidr_block } Best Practices Use semantic versioning for modules Document all variables with descriptions Provide examples in examples/ directory Use validation blocks for input validation Output important attributes for module composition Pin provider versions in versions.tf Use locals for computed values Implement conditional resources with count/for_each Test modules with Terratest Tag all resources consistently Reference: See references/aws-modules.md and references/oci-modules.md Module Composition module "vpc" { source = "../../modules/aws/vpc" name = "production" cidr_block = "10.0.0.0/16" availability_zones = ["us-west-2a", "us-west-2b", "us-west-2c"] private_subnet_cidrs = [ "10.0.1.0/24", "10.0.2.0/24", "10.0.3.0/24" ] tags = { Environment = "production" ManagedBy = "terraform" } } module "rds" { source = "../../modules/aws/rds" identifier = "production-db" engine = "postgres" engine_version = "15.3" instance_class = "db.t3.large" vpc_id = module.vpc.vpc_id subnet_ids = module.vpc.private_subnet_ids tags = { Environment = "production" } } Testing // tests/vpc_test.go package test import ( "testing" "github.com/gruntwork-io/terratest/modules/terraform" "github.com/stretchr/testify/assert" ) func TestVPCModule (t *testing.T) { terraformOptions := &terraform.Options{ TerraformDir: "../examples/complete" , } defer terraform.Destroy(t, terraformOptions) terraform.InitAndApply(t, terraformOptions) vpcID := terraform.Output(t, terraformOptions, "vpc_id" ) assert.NotEmpty(t, vpcID) } Related Skills multi-cloud-architecture - For architectural decisions cost-optimization - For cost-effective designs