terraform-module-library

# Terraform Module Library

Production-ready Terraform module patterns for AWS, Azure, and GCP 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/
```

## 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:**

```hcl
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:**

```hcl
variable