One codebase instead of copied infrastructure code

I moved live infrastructure, including StarSeed: Asnia Trigger (AWS, 50 servers and 20 databases), into IaC (managing infrastructure as code).

The same restructuring was applied to the Summoners War: Sky Arena environment.

Each environment (dev, staging, production) and each game used nearly identical Terraform code, copied by hand.

One change meant editing many places, and settings slowly drifted apart between environments.

I restructured the code with Terragrunt (a tool for reusing Terraform across environments without repetition).

• Shared modules and common settings (state storage location, cloud connection settings) are inherited from one place
• Each environment keeps only what differs

Structure example (for illustration)

infra/
├── modules/                 # shared modules (with security defaults)
│   ├── network/
│   ├── security-group/
│   └── server/
├── terragrunt.hcl           # common settings (state location, etc.)
└── game-a/
    ├── dev/
    │   └── terragrunt.hcl   # only what differs in dev
    ├── stg/
    │   └── terragrunt.hcl
    └── prod/
        └── terragrunt.hcl

Deployment time dropped 40%.

A security default added to a shared module now applies to every environment at once.