Code Organization

Repository Layout

Use a mono-repo structure with a clear separation between live infrastructure and reusable modules:

infrastructure/
├── environments/
│   ├── dev/
│   │   ├── main.tf
│   │   ├── variables.tf
│   │   ├── outputs.tf
│   │   └── terraform.tfvars
│   ├── staging/
│   └── prod/
└── modules/
    ├── networking/
    ├── rds_cluster/
    └── ecs_service/

• Each environment directory is an independent root module with its own state file.
• Shared logic lives exclusively in modules/. Copy-paste between environments is a red flag.

File Layout Within a Module

Every Terraform root module and reusable module must follow this file layout:

File	Purpose
main.tf	Core resource declarations
variables.tf	All variable blocks with descriptions and types
outputs.tf	All output blocks
versions.tf	terraform block with required_version and required_providers
locals.tf	All local blocks (omit if empty)
data.tf	All data source blocks (omit if empty)

Do not create files named resources.tf or split resources arbitrarily across files. Group by logical concern when a module is large (e.g. iam.tf, security_groups.tf).