# Configuration

This page lists the environment variables, process management settings, and storage layout.

## Environment Variables (`app/.env`)

| Variable | Required | `.env` value | Description |
|---|---|---|---|
| `NODE_PORT` | Yes | `8080` | Express listening port; must match the Nginx `proxy_pass` port |
| `NODE_ENV` | No | `production` | With `development`, the upload response `src` uses `http://localhost:8080/c/img`; otherwise `https://${DOMAIN}/c/img` |
| `DOMAIN` | When `NODE_ENV` is not `development` | — | Public domain used to build the upload response `src` |

`.env` is loaded by `dotenv`, which does not override variables already set; `docker-compose.yaml` sets `NODE_ENV: development`, so inside the container the compose value wins. For production, edit the compose `environment` block and set `DOMAIN`.

## Process Management

| Item | Setting | Location |
|---|---|---|
| Startup | `pm2-runtime` runs `app.ts` through `./node_modules/.bin/ts-node -r tsconfig-paths/register` | `app/app.json` |
| PM2 logs | `storage/logs/out.log`, `storage/logs/err.log` | `app/app.json` |
| Cluster | With more than one CPU, the primary forks `max(cpus.length, 4) - 1` workers and respawns any that exit; the primary does not listen | `app/app.ts` |
| Single core | With one CPU, nothing is forked and the same process listens | `app/app.ts` |
| Shutdown | On `SIGINT` / `SIGTERM` / `SIGHUP`, kills all workers and exits | `app/app.ts` |
| Path aliases | `@middlewares`, `@router`, `@src` | `app/tsconfig.json` |

## Storage Layout

| Path in container | Host mount (Docker Compose) | Purpose |
|---|---|---|
| `storage/image/upload/` | `./image/upload/` | Original uploads |
| `storage/image/cache/` | `./image/cache/` | Converted cache files |
| `storage/image/upload/.trash/` | `./image/upload/.trash/` | Deleted items |
| `storage/logs/` | `./logs/nodejs/` | `req.log` (rotated every 3 days) and PM2 logs |
| `storage/static/` | Not mounted (ships with the code) | `404-light.svg`, `404-dark.svg` |

Nginx logs are mounted at `./logs/nginx/`.

## Related Pages

- Nginx routing and caching: [Nginx](/deployment-nginx)