# left4me Deployment

This directory contains the production-like test deployment for a Linux server. It installs the repository into a fixed host layout, configures a dedicated runtime user, installs systemd units, and wires the web app to host operations through privileged helper commands.

## Target Layout

The deployment uses these paths:

- `/etc/left4me/host.env`: host library environment configuration.
- `/etc/left4me/web.env`: web app environment configuration.
- `/opt/left4me/.venv`: Python virtual environment for deployed commands.
- `/opt/left4me`: deployed repository contents.
- `/var/lib/left4me/left4me.db`: SQLite database used by the web app.
- `/var/lib/left4me/installation`: shared L4D2 installation.
- `/var/lib/left4me/overlays`: overlay directories. External (admin-managed) overlays still live at any relative path under here; new overlays created through the web UI use `${overlay_id}` as their path.
- `/var/lib/left4me/workshop_cache`: deduplicated cache of `.vpk` files downloaded for workshop overlays. One file per Steam item, named `{steam_id}.vpk`. Workshop overlays symlink into this tree.
- `/var/lib/left4me/instances`: rendered instance specifications and per-instance state.
- `/var/lib/left4me/runtime`: per-instance runtime mount directories.
- `/var/lib/left4me/tmp`: temporary files used by deployment/runtime operations.
- `/usr/local/lib/systemd/system`: global systemd unit files, including `left4me-server@.service`.
- `/usr/local/libexec/left4me`: privileged helper commands, including `left4me-systemctl` and `left4me-journalctl`.
- `/etc/sudoers.d/left4me`: sudoers rules allowing the web/runtime commands to call the helpers non-interactively.

Static units are generated for `/var/lib/left4me`. If `LEFT4ME_ROOT` changes, regenerate and reinstall the unit files instead of reusing the existing static units.

## Runtime User

The deployment creates and runs host operations as the dedicated runtime user:

- Username: `left4me`
- Home: `/var/lib/left4me`
- Shell: `/usr/sbin/nologin`

## Running A Test Deployment

Run the deployment from the repository root:

```bash
deploy/deploy-test-server.sh deploy-user@example-host
```

The SSH user must be able to run `sudo` on the target host. The deployment configures system packages, directories, environment files, helper scripts, sudoers rules, Python dependencies, and systemd units.

## Admin Bootstrap

Set the bootstrap credentials in the environment when creating the first admin user:

```bash
LEFT4ME_ADMIN_USERNAME=admin \
LEFT4ME_ADMIN_PASSWORD='change-me' \
flask create-user "$LEFT4ME_ADMIN_USERNAME" --admin
```

Use a strong one-time password and rotate it after first login if needed.

## Overlay References

Overlay references are relative paths below `${LEFT4ME_ROOT}/overlays`. With the default deployment root, they resolve under `/var/lib/left4me/overlays`.

Valid examples:

- `standard`
- `competitive/base`
- `users/42/custom`

Invalid references are rejected:

- Absolute paths such as `/srv/overlay`.
- Parent traversal such as `../other` or `competitive/../../base`.
- Empty path components such as `competitive//base`.
- Symlink escapes that resolve outside `${LEFT4ME_ROOT}/overlays`.

Overlay content for `external` (admin-managed) overlays is populated outside the host library — typically via SFTP. The web app does not write into them.

`workshop` overlays are populated by the web app: it downloads `.vpk` files from the public Steam Web API into `${LEFT4ME_ROOT}/workshop_cache/{steam_id}.vpk` and creates absolute symlinks under `${LEFT4ME_ROOT}/overlays/{overlay_id}/left4dead2/addons/{steam_id}.vpk`. Both the cache and the overlay directory are owned by the `left4me` runtime user; if the web service ever runs as a different uid, ensure it shares a group with the host process and that both trees are group-readable.