[Unit]
Description=BookStack MCP Server
Documentation=https://github.com/your/bookstack-mcp
After=network-online.target
Wants=network-online.target

[Service]
Type=exec
User=bookstack-mcp
Group=bookstack-mcp

EnvironmentFile=/etc/bookstack-mcp/env
WorkingDirectory=/opt/bookstack-mcp
ExecStart=/opt/bookstack-mcp/venv/bin/python -m bookstack_mcp

# ProtectSystem=strict makes everything read-only, but the MCP library writes
# to a data directory under $HOME (OAuth client registrations, caches). The
# service user's home is /opt/bookstack-mcp, which is part of the read-only
# tree -- so point HOME and the XDG dirs at directories systemd creates and
# grants write access to. Without this the service dies with
# "OSError: [Errno 30] Read-only file system: '/opt/bookstack-mcp/.local'".
StateDirectory=bookstack-mcp
CacheDirectory=bookstack-mcp
Environment=HOME=/var/lib/bookstack-mcp
Environment=XDG_DATA_HOME=/var/lib/bookstack-mcp
Environment=XDG_CONFIG_HOME=/var/lib/bookstack-mcp
Environment=XDG_CACHE_HOME=/var/cache/bookstack-mcp

Restart=on-failure
RestartSec=5s
TimeoutStopSec=20s

# --- Hardening ---
# These all work in an unprivileged Proxmox/LXD container. If the service fails
# with a 226/NAMESPACE or 227/SECCOMP status on an older kernel, comment out the
# block below and it will start fine -- it only reduces defence in depth.
NoNewPrivileges=yes
PrivateTmp=yes
ProtectSystem=strict
ProtectHome=yes
ProtectControlGroups=yes
RestrictSUIDSGID=yes
RemoveIPC=yes
LockPersonality=yes
MemoryDenyWriteExecute=yes
RestrictAddressFamilies=AF_INET AF_INET6 AF_UNIX
CapabilityBoundingSet=
AmbientCapabilities=

# Journald captures stdout/stderr: journalctl -u bookstack-mcp -f
StandardOutput=journal
StandardError=journal
SyslogIdentifier=bookstack-mcp

[Install]
WantedBy=multi-user.target