This Claude skill provides a comprehensive library of Terraform patterns and best practices specifically optimized for AWS infrastructure. It streamlines the development of Infrastructure as Code (IaC) by offering standardized module structures, advanced resource patterns, and robust state management configurations. By leveraging these expert-level templates, DevOps engineers and developers can ensure their cloud deployments are scalable, secure, and follow industry-standard architectural principles.

When should I use terraform?

terraform is useful in the following scenarios: • Architecting modular and reusable VPC structures with automated subnet distribution across multiple Availability Zones. • Implementing strict variable validation and data integrity checks to prevent configuration errors during infrastructure provisioning. • Managing complex AWS resources using dynamic blocks and conditional logic for flexible, environment-specific deployments. • Setting up secure remote state management with S3 backends and DynamoDB locking to facilitate safe team collaboration. • Applying standardized tagging strategies and resource governance across large-scale AWS environments for improved cost allocation and management.

name	terraform
description	Terraform patterns for AWS infrastructure. Use when writing IaC for cloud infrastructure.

Terraform (AWS Focus)

Module Structure

modules/
└── vpc/
    ├── main.tf       # Resources
    ├── variables.tf  # Input variables
    ├── outputs.tf    # Output values
    └── versions.tf   # Provider requirements

Variable Validation

variable "environment" {
  type        = string
  description = "Environment name"

  validation {
    condition     = contains(["dev", "staging", "prod"], var.environment)
    error_message = "Environment must be dev, staging, or prod."
  }
}

variable "instance_type" {
  type    = string
  default = "t3.micro"

  validation {
    condition     = can(regex("^t3\\.", var.instance_type))
    error_message = "Only t3 instance types allowed."
  }
}

Resource Patterns

# Conditional resource
resource "aws_eip" "nat" {
  count = var.enable_nat_gateway ? 1 : 0
  vpc   = true
}

# For each from map
resource "aws_subnet" "private" {
  for_each          = var.private_subnets
  vpc_id            = aws_vpc.main.id
  cidr_block        = each.value.cidr
  availability_zone = each.value.az

  tags = merge(local.common_tags, {
    Name = "${var.name}-private-${each.key}"
  })
}

# Dynamic blocks
resource "aws_security_group" "main" {
  dynamic "ingress" {
    for_each = var.ingress_rules
    content {
      from_port   = ingress.value.port
      to_port     = ingress.value.port
      protocol    = "tcp"
      cidr_blocks = ingress.value.cidrs
    }
  }
}

State Management

# Remote state backend
terraform {
  backend "s3" {
    bucket         = "my-terraform-state"
    key            = "env/prod/terraform.tfstate"
    region         = "us-east-1"
    encrypt        = true
    dynamodb_table = "terraform-locks"
  }
}

# Read remote state
data "terraform_remote_state" "vpc" {
  backend = "s3"
  config = {
    bucket = "my-terraform-state"
    key    = "env/prod/vpc/terraform.tfstate"
    region = "us-east-1"
  }
}

Common Patterns

# Locals for computed values
locals {
  common_tags = {
    Environment = var.environment
    ManagedBy   = "terraform"
    Project     = var.project
  }

  az_count = length(data.aws_availability_zones.available.names)
}

# Data sources
data "aws_availability_zones" "available" {
  state = "available"
}

data "aws_caller_identity" "current" {}

# Outputs
output "vpc_id" {
  value       = aws_vpc.main.id
  description = "VPC ID"
}

Best Practices

Use workspaces or separate state files per environment
Enable state locking with DynamoDB
Use terraform fmt and terraform validate
Pin provider versions
Use modules for reusable components
Tag all resources consistently
Use prevent_destroy for critical resources
Use create_before_destroy for zero-downtime updates
Store sensitive values in SSM/Secrets Manager
Run terraform plan in CI before apply

terraform

When & Why to Use This Skill

Use Cases