KetherServerDaemon

Daemon for managing Left 4 Dead 2 workshop and custom maps: installs VPKs, keeps a JSON registry, watches the addons folder, syncs with a remote backend, and exposes a local HTTP API plus interactive REPL.

Requirements

• Rust stable (see rust-toolchain.toml)
• Network access for Steam Workshop downloads and optional backend sync

Build

cargo build --release

Binary: target/release/KetherServerDaemon

Configuration

Configuration is loaded from config.toml (or path in KETHER_CONFIG). If the file does not exist, a commented default file is created on first startup. Environment variables override file values:

Variable	Description
KETHER_CONFIG	Path to config TOML
KETHER_L4D2_SERVER_DIR	L4D2 server root (addons at {dir}/left4dead2/addons)
KETHER_REGISTRY_PATH	JSON map registry file
KETHER_BACKEND_API_URL	Remote sync API base URL (website-server: http://127.0.0.1:3001/api)
KETHER_BACKEND_API_KEY	Shared bearer token for backend sync and inbound API (must match website-server [server_daemon].sync_api_key)
KETHER_LOCAL_API_BIND	Local HTTP API bind address (default 127.0.0.1:8080)
KETHER_SYNC_INTERVAL_SECS	Backend sync interval
KETHER_LOG_LEVEL	trace, debug, info, warn, error
KETHER_MAX_DOWNLOAD_SIZE_BYTES	Max download size (default 1GB)
KETHER_MAX_EXTRACTION_SIZE_BYTES	Max ZIP extraction size
KETHER_MAX_EXTRACTION_FILE_COUNT	Max files per archive
KETHER_L4D2CENTER_INDEX_URL	L4D2Center catalog index URL
KETHER_MAP_UPDATE_CHECK_INTERVAL_DAYS	Shared workshop/L4D2Center update check interval in days (default 3; first check waits one full interval after startup)
KETHER_WORKSHOP_UPDATE_CHECK_ENABLED	Enable periodic workshop update checks (default true)
KETHER_WORKSHOP_UPDATE_AUTO_APPLY	Auto-download workshop updates when found (default true)
KETHER_L4D2CENTER_UPDATE_CHECK_ENABLED	Enable periodic L4D2Center update checks (default true)
KETHER_L4D2CENTER_UPDATE_AUTO_APPLY	Auto-download L4D2Center updates when found (default false)

REPL commands

Command	Description
ls / maps	List installed maps
i <url|workshop_id> [name]	Install map
rm <id>	Uninstall map
u [id] [--check] [--force]	Check or update workshop maps
d [u|U]	Discover local VPKs (u = refresh metadata)
compact	Prune orphaned registry entries and reindex IDs
info <id>	Show map details
modify <id> <field> <value>	Edit registry field
S / stop	Stop daemon

HTTP API

Default bind: http://127.0.0.1:8080

All /api/* routes require Authorization: Bearer <backend_api_key> when backend_api_key is configured. /health remains unauthenticated. A non-loopback local_api_bind is rejected at startup unless this key is set.

Method	Path	Description
GET	/health	Health check
GET	/api/maps	List maps
GET	/api/maps/updates/available	Pending + in-progress updates ({ available, in_progress })
GET	/api/maps/{id}	Get map
PATCH	/api/maps/{id}	Modify map field
POST	/api/maps/install	Install from URL or workshop ID
POST	/api/maps/uninstall/{id}	Uninstall map
POST	/api/maps/workshop/update	Update workshop maps (check_only, force)
POST	/api/maps/discover	Scan addons directory
POST	/api/maps/compact	Compact registry

Responses use { "success": true, "data": ... } or { "success": false, "error": "..." }.

Backend sync (website-server)

The daemon pushes its map registry to the website backend and polls for pending updates:

Method	Path (relative to backend_api_url)	Auth
POST	/registry/sync	Authorization: Bearer <backend_api_key>
GET	/registry/updates	same Bearer token

Example config.toml when website-server runs on port 3001:

backend_api_url = "http://127.0.0.1:3001/api"backend_api_key = "your-shared-secret"

The public website reads installed maps from GET http://127.0.0.1:3001/api/maps (no auth).

Cross-host website-server access

When website-server runs on another host, bind the daemon to an address reachable from that host and configure a shared inbound API key:

local_api_bind = "0.0.0.0:8080"backend_api_key = "a-long-random-secret"

Set the same value as website-server's [server_daemon].sync_api_key, and set its daemon_url to this daemon's reachable HTTP address. The daemon API is plain HTTP, so firewall port 8080 to the website-server's source IP only. Prefer a private VPN/tunnel or a TLS reverse proxy for traffic crossing an untrusted network.

Systemd

Example user unit: .config/systemd/user/ksd.service

Tests

cargo test
cargo clippy
cargo fmt --check