# Configuration

This page lists the environment variables the Go service reads, the storage directory layout, and the Docker Compose defaults.

## Environment Variables

| Variable | Default | Read by | Description |
|---|---|---|---|
| `GO_ENV` | — | `configs.ModeDev()` | `development` enables development mode |
| `PORT` | `8080` | `configs.GetPort()` | Go service listen port |
| `DOMAIN` | — | `configs.GetDomain()` | Outside development mode, upload response `src` uses `https://{DOMAIN}` |

`GetDomain()` affects only the `src` in upload responses, not routing or caching.

## Docker Compose Defaults

`docker-compose.yaml` sets `GO_ENV: development` and `DOMAIN: "joball.tw"` on the `golang` service. Because `GO_ENV` is `development`, `DOMAIN` has no effect and upload responses return `src` as `http://localhost:8080/...`. In production, remove `GO_ENV` and set `DOMAIN` to the real public domain.

## Storage Layout

All paths resolve against the working directory (`os.Getwd()`):

| Path | Function | Purpose |
|---|---|---|
| `storage/image/upload/` | `GetUploadPath()` | Original uploads |
| `storage/image/cache/` | `GetCachePath()` | Transform cache, mirroring `upload/` |
| `storage/image/upload/.trash/` | `GetTrashPath()` | Trash, bucketed by date |
| `internal/assets/image/404-{light,dark}.svg` | `Get404SVG()` | Placeholder for failed reads |

Docker Compose mounts the host's `./image` to `storage/image` in the container, so that one directory is all you need to back up or migrate.