terraform

# Terraform & OpenTofu ## File Organization & Naming | File | Purpose | |------|---------| | `terraform.tf` | Terraform + provider version requirements | | `providers.tf` | Provider configurations | | `main.tf` | Primary resources and data sources | | `variables.tf` | Input variables (alphabetical) | | `outputs.tf` | Output values (alphabetical) | | `locals.tf` | Local values | - Lowercase with underscores: `web_api`, not `webAPI` or `web-api` - Descriptive nouns excluding resource type: `aws_instance.web_api` not `aws_instance.web_api_instance` - Singular, not plural - `this` for singleton resources (one of that type per module) - Contextual variable prefixes: `vpc_cidr_block` not `cidr` ## Block Ordering **Resources:** `count`/`for_each` (blank line after) → arguments → nested blocks → `tags` → `depends_on` → `lifecycle` (last) **Variables:** `description` → `type` → `default` → `validation` → `nullable` Every variable needs `type` + `description`. Every output needs `description`. Mark secrets `sensitive = true`. ## Module Structure | Type | Scope | Example | |------|-------|---------| | Resource Module | Single logical group | VPC + subnets, SG + rules | | Infrastructure Module | Collection of resource modules | Networking + compute for one region | | Composition | Complete infrastructure | Spans regions/accounts | ``` module-name/ ├── main.tf, variables.tf, outputs.tf, versions.tf ├── examples/ │ ├── minimal/ │ └── complete/ └── tests/ └── defaults.tfte...