terraform-generator
Terraform Generator
Overview
This skill enables the generation of production-ready Terraform configurations following best practices and current standards. Automatically integrates validation and documentation lookup for custom providers and modules.
Critical Requirements Checklist
STOP: You MUST complete ALL steps in order. Do NOT skip any REQUIRED step.
| Step | Action | Required |
|---|---|---|
| 1 | Understand requirements (providers, resources, modules) | ✅ REQUIRED |
| 2 | Check for custom providers/modules and lookup documentation | ✅ REQUIRED |
| 3 | Consult reference files before generation | ✅ REQUIRED |
| 4 | Generate Terraform files with ALL best practices | ✅ REQUIRED |
| 5 | Include data sources for dynamic values (region, account, AMIs) | ✅ REQUIRED |
| 6 | Add lifecycle rules on critical resources (KMS, databases) | ✅ REQUIRED |
| 7 | Invoke Skill(devops-skills:terraform-validator) |
✅ REQUIRED |
| 8 | FIX all validation/security failures and RE-VALIDATE | ✅ REQUIRED |
| 9 | Provide usage instructions (files, next steps, security) | ✅ REQUIRED |
IMPORTANT: If validation fails (terraform validate OR security scan), you MUST fix the issues and re-run validation until ALL checks pass. Do NOT proceed to Step 9 with failing checks.
Core Workflow
When generating Terraform configurations, follow this workflow:
Step 1: Understand Requirements
Analyze the user's request to determine:
- What infrastructure resources need to be created
- Which Terraform providers are required (AWS, Azure, GCP, custom, etc.)
- Whether any modules are being used (official, community, or custom)
- Version constraints for providers and modules
- Variable inputs and outputs needed
- State backend configuration (local, S3, remote, etc.)
Step 2: Check for Custom Providers/Modules
Before generating configurations, identify if custom or third-party providers/modules are involved:
Standard providers (no lookup needed):
- hashicorp/aws
- hashicorp/azurerm
- hashicorp/google
- hashicorp/kubernetes
- Other official HashiCorp providers
Custom/third-party providers/modules (require documentation lookup):
- Third-party providers (e.g., datadog/datadog, mongodb/mongodbatlas)
- Custom modules from Terraform Registry
- Private or company-specific modules
- Community modules
When custom providers/modules are detected:
-
Use WebSearch to find version-specific documentation:
Search query format: "[provider/module name] terraform [version] documentation [specific resource]" Example: "datadog terraform provider v3.30 monitor resource documentation" Example: "terraform-aws-modules vpc version 5.0 documentation" -
Focus searches on:
- Official documentation (registry.terraform.io, provider websites)
- Required and optional arguments
- Attribute references
- Example usage
- Version compatibility notes
-
If Context7 MCP is available and the provider/module is supported, use it as an alternative:
mcp__context7__resolve-library-id → mcp__context7__get-library-docs
Step 2.5: Consult Reference Files (REQUIRED)
Before generating configuration, you MUST read the relevant reference files:
Read(file_path: ".claude/skills/terraform-generator/references/terraform_best_practices.md")
Read(file_path: ".claude/skills/terraform-generator/references/provider_examples.md")
When to consult each reference:
| Reference | Read When |
|---|---|
terraform_best_practices.md |
Always - contains required patterns |
common_patterns.md |
Multi-environment, workspace, or complex setups |
provider_examples.md |
Generating AWS, Azure, GCP, or K8s resources |
Step 3: Generate Terraform Configuration
Generate HCL files following best practices:
File Organization:
terraform-project/
├── main.tf # Primary resource definitions
├── variables.tf # Input variable declarations
├── outputs.tf # Output value declarations
├── versions.tf # Provider version constraints
├── terraform.tfvars # Variable values (optional, for examples)
└── backend.tf # Backend configuration (optional)
Best Practices to Follow:
-
Provider Configuration:
terraform { required_version = ">= 1.10, < 2.0" required_providers { aws = { source = "hashicorp/aws" version = "~> 6.0" # Latest: v6.23.0 (Dec 2025) } } } provider "aws" { region = var.aws_region } -
Resource Naming:
- Use descriptive resource names
- Follow snake_case convention
- Include resource type in name when helpful
resource "aws_instance" "web_server" { # ... } -
Variable Declarations:
variable "instance_type" { description = "EC2 instance type for web servers" type = string default = "t3.micro" validation { condition = contains(["t3.micro", "t3.small", "t3.medium"], var.instance_type) error_message = "Instance type must be t3.micro, t3.small, or t3.medium." } } -
Output Values:
output "instance_public_ip" { description = "Public IP address of the web server" value = aws_instance.web_server.public_ip } -
Use Data Sources for References:
data "aws_ami" "ubuntu" { most_recent = true owners = ["099720109477"] # Canonical filter { name = "name" values = ["ubuntu/images/hvm-ssd/ubuntu-jammy-22.04-amd64-server-*"] } } -
Module Usage:
module "vpc" { source = "terraform-aws-modules/vpc/aws" version = "5.0.0" name = "my-vpc" cidr = "10.0.0.0/16" azs = ["us-east-1a", "us-east-1b"] private_subnets = ["10.0.1.0/24", "10.0.2.0/24"] public_subnets = ["10.0.101.0/24", "10.0.102.0/24"] } -
Use locals for Computed Values:
locals { common_tags = { Environment = var.environment ManagedBy = "Terraform" Project = var.project_name } } -
Lifecycle Rules When Appropriate:
resource "aws_instance" "example" { # ... lifecycle { create_before_destroy = true prevent_destroy = true ignore_changes = [tags] } } -
Dynamic Blocks for Repeated Configuration:
resource "aws_security_group" "example" { # ... dynamic "ingress" { for_each = var.ingress_rules content { from_port = ingress.value.from_port to_port = ingress.value.to_port protocol = ingress.value.protocol cidr_blocks = ingress.value.cidr_blocks } } } -
Comments and Documentation:
- Add comments explaining complex logic
- Document why certain values are used
- Include examples in variable descriptions
Security Best Practices:
- Never hardcode sensitive values (use variables)
- Use data sources for AMIs and other dynamic values
- Implement least-privilege IAM policies
- Enable encryption by default
- Use secure backend configurations
Required: Data Sources for Dynamic Values
You MUST include data sources for dynamic infrastructure values. Do NOT hardcode these:
# REQUIRED: Current AWS region and account info
data "aws_region" "current" {}
data "aws_caller_identity" "current" {}
# Use in resources
locals {
account_id = data.aws_caller_identity.current.account_id
region = data.aws_region.current.name
}
Common required data sources:
| Use Case | Data Source |
|---|---|
| Current region | data "aws_region" "current" {} |
| Current account | data "aws_caller_identity" "current" {} |
| Available AZs | data "aws_availability_zones" "available" {} |
| Latest AMI | data "aws_ami" "..." with filters |
| Existing VPC | data "aws_vpc" "..." |
Required: Lifecycle Rules on Critical Resources
You MUST add lifecycle rules on resources that could cause data loss or service disruption if accidentally destroyed:
# KMS Keys - ALWAYS protect from deletion
resource "aws_kms_key" "encryption" {
# ...
lifecycle {
prevent_destroy = true
}
}
# Databases - ALWAYS protect from deletion
resource "aws_db_instance" "main" {
# ...
lifecycle {
prevent_destroy = true
}
}
# S3 Buckets with data - protect from deletion
resource "aws_s3_bucket" "data" {
# ...
lifecycle {
prevent_destroy = true
}
}
Resources that MUST have prevent_destroy = true:
- KMS keys (
aws_kms_key) - RDS databases (
aws_db_instance,aws_rds_cluster) - S3 buckets containing data
- DynamoDB tables with data
- ElastiCache clusters
- Secrets Manager secrets
Required: S3 Lifecycle Best Practices
When creating S3 buckets with lifecycle configurations, ALWAYS include a rule to abort incomplete multipart uploads:
resource "aws_s3_bucket_lifecycle_configuration" "main" {
bucket = aws_s3_bucket.main.id
# REQUIRED: Abort incomplete multipart uploads to prevent storage costs
rule {
id = "abort-incomplete-uploads"
status = "Enabled"
# Filter applies to all objects (empty filter = all objects)
filter {}
abort_incomplete_multipart_upload {
days_after_initiation = 7
}
}
# Other lifecycle rules (e.g., transition to IA)
rule {
id = "transition-to-ia"
status = "Enabled"
filter {
prefix = "" # Apply to all objects
}
transition {
days = 90
storage_class = "STANDARD_IA"
}
noncurrent_version_transition {
noncurrent_days = 30
storage_class = "STANDARD_IA"
}
noncurrent_version_expiration {
noncurrent_days = 365
}
}
}
Why? Incomplete multipart uploads consume storage and incur costs. Checkov check
CKV_AWS_300enforces this. Always include this rule.
Step 4: Validate Generated Configuration (REQUIRED)
After generating Terraform files, ALWAYS validate them using the devops-skills:terraform-validator skill:
Invoke: Skill(devops-skills:terraform-validator)
The devops-skills:terraform-validator skill will:
- Check HCL syntax with
terraform fmt -check - Initialize the configuration with
terraform init - Validate the configuration with
terraform validate - Run security scan with Checkov
- Perform dry-run testing (if requested) with
terraform plan
CRITICAL: Fix-and-Revalidate Loop
If ANY validation or security check fails, you MUST:
- Review the error - Understand what failed and why
- Fix the issue - Edit the generated file to resolve the problem
- Re-run validation - Invoke
Skill(devops-skills:terraform-validator)again - Repeat until ALL checks pass - Do NOT proceed with failing checks
┌─────────────────────────────────────────────────────────┐
│ VALIDATION FAILED? │
│ │
│ ┌─────────┐ ┌─────────┐ ┌─────────────────────┐ │
│ │ Fix │───▶│ Re-run │───▶│ All checks pass? │ │
│ │ Issue │ │ Skill │ │ YES → Step 5 │ │
│ └─────────┘ └─────────┘ │ NO → Loop back │ │
│ ▲ └─────────────────────┘ │
│ │ │ │
│ └────────────────────────────────────┘ │
└─────────────────────────────────────────────────────────┘
Common validation failures to fix:
| Check | Issue | Fix |
|---|---|---|
CKV_AWS_300 |
Missing abort multipart upload | Add abort_incomplete_multipart_upload rule |
CKV_AWS_24 |
SSH open to 0.0.0.0/0 | Restrict to specific CIDR |
CKV_AWS_16 |
RDS encryption disabled | Add storage_encrypted = true |
terraform validate |
Invalid resource argument | Check provider documentation |
If custom providers are detected during validation:
- The devops-skills:terraform-validator skill will automatically fetch documentation
- Use the fetched documentation to fix any issues
Step 5: Provide Usage Instructions (REQUIRED)
After successful generation and validation with ALL checks passing, you MUST provide the user with:
Required Output Format:
## Generated Files
| File | Description |
|------|-------------|
| `path/to/main.tf` | Main resource definitions |
| `path/to/variables.tf` | Input variables |
| `path/to/outputs.tf` | Output values |
| `path/to/versions.tf` | Provider version constraints |
## Next Steps
1. Review and customize `terraform.tfvars` with your values
2. Initialize Terraform:
```bash
terraform init
- Review the execution plan:
terraform plan - Apply the configuration:
terraform apply
Customization Notes
- Update
variable_namein terraform.tfvars - Configure backend in backend.tf for remote state
- Adjust resource names/tags as needed
Security Reminders
⚠️ Before applying:
- Review IAM policies and permissions
- Ensure sensitive values are NOT committed to version control
- Configure state backend with encryption enabled
- Set up state locking for team collaboration
> **IMPORTANT:** Do NOT skip Step 5. The user needs actionable guidance on how to use the generated configuration.
## Common Generation Patterns
### Pattern 1: Simple Resource Creation
User request: "Create an AWS S3 bucket with versioning"
Generated files:
- `main.tf` - S3 bucket resource with versioning enabled
- `variables.tf` - Bucket name, tags variables
- `outputs.tf` - Bucket ARN and name outputs
- `versions.tf` - AWS provider version constraints
### Pattern 2: Module-Based Infrastructure
User request: "Set up a VPC using the official AWS VPC module"
Actions:
1. Identify module: terraform-aws-modules/vpc/aws
2. Web search for latest version and documentation
3. Generate configuration using module with appropriate inputs
4. Validate with devops-skills:terraform-validator
### Pattern 3: Multi-Provider Configuration
User request: "Create infrastructure across AWS and Datadog"
Actions:
1. Identify standard provider (AWS) and custom provider (Datadog)
2. Web search for Datadog provider documentation with version
3. Generate configuration with both providers properly configured
4. Ensure provider aliases if needed
5. Validate with devops-skills:terraform-validator
### Pattern 4: Complex Resource with Dependencies
User request: "Create an ECS cluster with ALB and auto-scaling"
Generated structure:
- Multiple resource blocks with proper dependencies
- Data sources for AMIs, availability zones, etc.
- Local values for computed configurations
- Comprehensive variables and outputs
- Proper dependency management using implicit references
## Error Handling
**Common Issues and Solutions:**
1. **Provider Not Found:**
- Ensure provider is listed in `required_providers` block
- Verify source address format: `namespace/name`
- Check version constraint syntax
2. **Invalid Resource Arguments:**
- Refer to web search results for custom providers
- Check for required vs optional arguments
- Verify attribute value types (string, number, bool, list, map)
3. **Circular Dependencies:**
- Review resource references
- Use `depends_on` explicit dependencies if needed
- Consider breaking into separate modules
4. **Validation Failures:**
- Run devops-skills:terraform-validator skill to get detailed errors
- Fix issues one at a time
- Re-validate after each fix
## Version Awareness
Always consider version compatibility:
1. **Terraform Version:**
- Use `required_version` constraint with both lower and upper bounds
- Default to `>= 1.10, < 2.0` for modern features (ephemeral resources, write-only)
- Use `>= 1.14, < 2.0` for latest features (actions, query command)
- Document any version-specific features used (see below)
2. **Provider Versions (as of December 2025):**
- AWS: `~> 6.0` (latest: v6.23.0)
- Azure: `~> 4.0` (latest: v4.54.0)
- GCP: `~> 7.0` (latest: v7.12.0) - 7.0 includes ephemeral resources & write-only attributes
- Kubernetes: `~> 2.23`
- Use `~>` for minor version flexibility, pin major versions
3. **Module Versions:**
- Always pin module versions
- Review module documentation for version compatibility
- Test module updates in non-production first
### Terraform Version Feature Matrix
| Feature | Minimum Version |
|---------|-----------------|
| `terraform_data` resource | 1.4+ |
| `import {}` blocks | 1.5+ |
| `check {}` blocks | 1.5+ |
| Native testing (`.tftest.hcl`) | 1.6+ |
| Test mocking | 1.7+ |
| `removed {}` blocks | 1.7+ |
| Provider-defined functions | 1.8+ |
| Cross-type refactoring | 1.8+ |
| Enhanced variable validations | 1.9+ |
| `templatestring` function | 1.9+ |
| Ephemeral resources | 1.10+ |
| Write-only arguments | 1.11+ |
| S3 native state locking | 1.11+ |
| Import blocks with `for_each` | 1.12+ |
| Actions block | 1.14+ |
| List resources (`tfquery.hcl`) | 1.14+ |
| `terraform query` command | 1.14+ |
## Modern Terraform Features (1.8+)
### Provider-Defined Functions (Terraform 1.8+)
Provider-defined functions extend Terraform's built-in functions with provider-specific logic.
**Syntax:** `provider::<provider_name>::<function_name>(arguments)`
```hcl
# AWS Provider Functions (v5.40+)
locals {
# Parse an ARN into components
parsed_arn = provider::aws::arn_parse(aws_instance.web.arn)
account_id = local.parsed_arn.account
region = local.parsed_arn.region
# Build an ARN from components
custom_arn = provider::aws::arn_build({
partition = "aws"
service = "s3"
region = ""
account = ""
resource = "my-bucket/my-key"
})
}
# Google Cloud Provider Functions (v5.23+)
locals {
# Extract region from zone
region = provider::google::region_from_zone(var.zone) # "us-west1-a" → "us-west1"
}
# Kubernetes Provider Functions (v2.28+)
locals {
# Encode HCL to Kubernetes manifest YAML
manifest_yaml = provider::kubernetes::manifest_encode(local.deployment_config)
}
Ephemeral Resources (Terraform 1.10+)
Ephemeral resources provide temporary values that are never persisted in state or plan files. Critical for handling secrets securely.
# Generate a password that never touches state
ephemeral "random_password" "db_password" {
length = 16
special = true
override_special = "!#$%&*()-_=+[]{}<>:?"
}
# Fetch secrets ephemerally from AWS Secrets Manager
ephemeral "aws_secretsmanager_secret_version" "api_key" {
secret_id = aws_secretsmanager_secret.api_key.id
}
# Ephemeral variables (declare with ephemeral = true)
variable "temporary_token" {
type = string
ephemeral = true # Value won't be stored in state
}
# Ephemeral outputs
output "session_token" {
value = ephemeral.aws_secretsmanager_secret_version.api_key.secret_string
ephemeral = true # Won't be stored in state
}
Write-Only Arguments (Terraform 1.11+)
Write-only arguments accept ephemeral values and are never persisted. They use _wo suffix and require a version attribute.
# Secure database password handling
ephemeral "random_password" "db_password" {
length = 16
}
resource "aws_db_instance" "main" {
identifier = "mydb"
instance_class = "db.t3.micro"
allocated_storage = 20
engine = "postgres"
username = "admin"
# Write-only password - never stored in state!
password_wo = ephemeral.random_password.db_password.result
password_wo_version = 1 # Increment to trigger password rotation
skip_final_snapshot = true
}
# Secrets Manager with write-only
resource "aws_secretsmanager_secret_version" "db_password" {
secret_id = aws_secretsmanager_secret.db_password.id
# Write-only secret string
secret_string_wo = ephemeral.random_password.db_password.result
secret_string_wo_version = 1
}
Enhanced Variable Validations (Terraform 1.9+)
Validation conditions can now reference other variables, data sources, and local values.
# Reference data sources in validation
data "aws_ec2_instance_type_offerings" "available" {
filter {
name = "location"
values = [var.availability_zone]
}
}
variable "instance_type" {
type = string
description = "EC2 instance type"
validation {
# NEW: Can reference data sources
condition = contains(
data.aws_ec2_instance_type_offerings.available.instance_types,
var.instance_type
)
error_message = "Instance type ${var.instance_type} is not available in the selected AZ."
}
}
# Cross-variable validation
variable "min_instances" {
type = number
default = 1
}
variable "max_instances" {
type = number
default = 10
validation {
# NEW: Can reference other variables
condition = var.max_instances >= var.min_instances
error_message = "max_instances must be >= min_instances"
}
}
S3 Native State Locking (Terraform 1.11+)
S3 now supports native state locking without DynamoDB.
terraform {
backend "s3" {
bucket = "my-terraform-state"
key = "project/terraform.tfstate"
region = "us-east-1"
encrypt = true
# NEW: S3-native locking (Terraform 1.11+)
use_lockfile = true
# DEPRECATED: DynamoDB locking (still works but no longer required)
# dynamodb_table = "terraform-locks"
}
}
Import Blocks (Terraform 1.5+)
Declarative resource imports without command-line operations.
# Import existing resources declaratively
import {
to = aws_instance.web
id = "i-1234567890abcdef0"
}
resource "aws_instance" "web" {
ami = "ami-0c55b159cbfafe1f0"
instance_type = "t3.micro"
# ... configuration must match existing resource
}
# Import with for_each
import {
for_each = var.existing_bucket_names
to = aws_s3_bucket.imported[each.key]
id = each.value
}
Moved and Removed Blocks
Safely refactor resources without destroying them.
# Rename a resource
moved {
from = aws_instance.old_name
to = aws_instance.new_name
}
# Move to a module
moved {
from = aws_vpc.main
to = module.networking.aws_vpc.main
}
# Cross-type refactoring (1.8+)
moved {
from = null_resource.example
to = terraform_data.example
}
# Remove resource from state without destroying (1.7+)
removed {
from = aws_instance.legacy
lifecycle {
destroy = false # Keep the actual resource, just remove from state
}
}
Import Blocks with for_each (Terraform 1.12+)
Import multiple resources using for_each meta-argument.
# Import multiple S3 buckets using a map
locals {
buckets = {
"staging" = "bucket1"
"uat" = "bucket2"
"prod" = "bucket3"
}
}
import {
for_each = local.buckets
to = aws_s3_bucket.this[each.key]
id = each.value
}
resource "aws_s3_bucket" "this" {
for_each = local.buckets
}
# Import across module instances using list of objects
locals {
module_buckets = [
{ group = "one", key = "bucket1", id = "one_1" },
{ group = "one", key = "bucket2", id = "one_2" },
{ group = "two", key = "bucket1", id = "two_1" },
]
}
import {
for_each = local.module_buckets
id = each.value.id
to = module.group[each.value.group].aws_s3_bucket.this[each.value.key]
}
Actions Block (Terraform 1.14+)
Actions enable provider-defined operations outside the standard CRUD model. Use for operations like Lambda invocations, cache invalidations, or database backups.
# Invoke a Lambda function (example syntax)
action "aws_lambda_invoke" "process_data" {
function_name = aws_lambda_function.processor.function_name
payload = jsonencode({ action = "process" })
}
# Create CloudFront invalidation
action "aws_cloudfront_create_invalidation" "invalidate_cache" {
distribution_id = aws_cloudfront_distribution.main.id
paths = ["/*"]
}
# Actions support for_each
action "aws_lambda_invoke" "batch_process" {
for_each = toset(["task1", "task2", "task3"])
function_name = aws_lambda_function.processor.function_name
payload = jsonencode({ task = each.value })
}
Triggering Actions via Lifecycle:
Use action_trigger within a resource's lifecycle block to automatically invoke actions:
resource "aws_lambda_function" "example" {
function_name = "my-function"
# ... other config ...
lifecycle {
action_trigger {
events = [after_create, after_update]
actions = [action.aws_lambda_invoke.process_data]
}
}
}
action "aws_lambda_invoke" "process_data" {
function_name = aws_lambda_function.example.function_name
payload = jsonencode({ action = "initialize" })
}
Manual Invocation:
Actions can also be invoked manually via CLI:
terraform apply -invoke action.aws_lambda_invoke.process_data
List Resources and Query Command (Terraform 1.14+)
Query and filter existing infrastructure using .tfquery.hcl files and the terraform query command.
# my-resources.tfquery.hcl
# Define list resources to query existing infrastructure
list "aws_instance" "web_servers" {
filter {
name = "tag:Environment"
values = [var.environment]
}
include_resource = true # Include full resource details
}
list "aws_s3_bucket" "data_buckets" {
filter {
name = "tag:Purpose"
values = ["data-storage"]
}
}
# Query infrastructure and output results
terraform query
# Generate import configuration from query results
terraform query -generate-config-out="import_config.tf"
# Output in JSON format
terraform query -json
# Use with variables
terraform query -var 'environment=prod'
Preconditions and Postconditions (Terraform 1.5+)
Add custom validation within resource lifecycle.
resource "aws_instance" "example" {
instance_type = "t3.micro"
ami = data.aws_ami.example.id
lifecycle {
# Check before creation
precondition {
condition = data.aws_ami.example.architecture == "x86_64"
error_message = "The selected AMI must be for the x86_64 architecture."
}
# Verify after creation
postcondition {
condition = self.public_dns != ""
error_message = "EC2 instance must be in a VPC that has public DNS hostnames enabled."
}
}
}
# Preconditions on outputs
output "web_url" {
value = "https://${aws_instance.web.public_dns}"
precondition {
condition = aws_instance.web.public_dns != ""
error_message = "Instance must have a public DNS name."
}
}
Resources
references/
The references/ directory contains detailed documentation for reference:
terraform_best_practices.md- Comprehensive best practices guidecommon_patterns.md- Common Terraform patterns and examplesprovider_examples.md- Example configurations for popular providers
To load a reference, use the Read tool:
Read(file_path: ".claude/skills/terraform-generator/references/[filename].md")
assets/
The assets/ directory contains template files:
minimal-project/- Minimal Terraform project templateaws-web-app/- AWS web application infrastructure templatemulti-env/- Multi-environment configuration template
Templates can be copied and customized for the user's specific needs.
Notes
- Always run devops-skills:terraform-validator after generation
- Web search is essential for custom providers/modules
- Follow the principle of least surprise in configurations
- Make configurations readable and maintainable
- Include helpful comments and documentation
- Generate realistic examples in terraform.tfvars when helpful