OpenTofu HCL Naming Conventions

This rule applies to files matching the patterns above.

# OpenTofu HCL Naming Conventions

## Rule
All OpenTofu resources, variables, outputs, and files MUST follow consistent naming: snake_case for HCL identifiers, kebab-case for cloud resource names, and standard file layout.

## Format
```hcl
# Resources: type + descriptive name (snake_case)
resource "aws_instance" "web_server" {}

# Variables: descriptive snake_case
variable "vpc_cidr_block" {}

# Outputs: descriptive snake_case
output "database_endpoint" {}
```

## File Organization
```
module/
├── main.tf           # Primary resources
├── variables.tf      # All input variables
├── outputs.tf        # All outputs
├── versions.tf       # Provider and OpenTofu version constraints
├── locals.tf         # Local values
├── data.tf           # Data sources
└── README.md         # Module documentation
```

## Good Examples
```hcl
# versions.tf — pin OpenTofu and provider versions
terraform {
  required_version = ">= 1.7.0"

  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.40"
    }
  }
}

# variables.tf — with descriptions and validation
variable "environment" {
  type        = string
  description = "Deployment environment name"
  validation {
    condition     = contains(["dev", "staging", "production"], var.environment)
    error_message = "Environment must be dev, staging, or production."
  }
}

# Cloud resource naming pattern
locals {
  name_prefix = "${var.project}-${var.environment}"
}

resource "aws_vpc" "main" {
  cidr_block = var.vpc_cidr_block
  tags       = { Name = "${local.name_prefix}-vpc" }
}
```

## Bad Examples
```hcl
# BAD: PascalCase resource names
resource "aws_instance" "WebServer" {}

# BAD: No file organization
# Everything in one giant main.tf

# BAD: No variable descriptions
variable "x" { type = string }
```

## Enforcement
- `tofu fmt -check` in CI to verify formatting
- tflint for naming convention rules
- Code review checklist for naming and organization