ubuntu-post-install/services/watchyourlan.sh

#!/bin/bash
# services/watchyourlan.sh — WatchYourLAN network device tracker.
# Part of the modular post-install system (sourced by setup.sh).
#
# Continuously scans the network for connected devices, tracks history,
# and can alert on new/unknown devices. Uses network_mode: host so it
# can see the physical network directly (required for ARP scanning).

register_service watchyourlan utilities "Network device tracker (WatchYourLAN)" 8840

install_watchyourlan() {
    require_docker || return 1
    log_info "Installing WatchYourLAN..."
    local WYL_DIR="$DOCKER_DIR/watchyourlan"

    if [ "$DRY_RUN" = true ]; then
        echo "[DRY-RUN] Would create $WYL_DIR (watchyourlan_data/)"
        echo "[DRY-RUN] Would deploy aceberg/watchyourlan:latest (network_mode: host)"
        echo "[DRY-RUN] Port 8840 on host, needs network interface name"
        return 0
    fi

    mkdir -p "$WYL_DIR/watchyourlan_data"
    ensure_docker_dir_ownership "$WYL_DIR"
    cd "$WYL_DIR" || return 1

    local TZ_VAL="${SITE_TZ:-$(cat /etc/timezone 2>/dev/null || echo UTC)}"

    # Auto-detect primary network interface
    local DEFAULT_IFACE
    DEFAULT_IFACE=$(ip route show default 2>/dev/null | awk '/default/ {print $5; exit}')
    [ -z "$DEFAULT_IFACE" ] && DEFAULT_IFACE="eth0"

    echo ""
    echo "  WatchYourLAN needs to know which network interface to scan."
    echo "  Your detected primary interface: $DEFAULT_IFACE"
    echo ""
    ip link show 2>/dev/null | awk -F: '/^[0-9]+: / && !/lo/ {gsub(/ /,"",$2); print "  •", $2}' || true
    echo ""
    local SCAN_IFACE=""
    prompt_text "Network interface to scan:" "$DEFAULT_IFACE" SCAN_IFACE
    [ -z "$SCAN_IFACE" ] && SCAN_IFACE="$DEFAULT_IFACE"

    local GUI_PORT="8840"
    prompt_text "GUI port [8840]:" "8840" GUI_PORT
    [ -z "$GUI_PORT" ] && GUI_PORT="8840"

    cat > docker-compose.yml << 'WYL_COMPOSE'
name: watchyourlan

services:
  watchyourlan:
    image: aceberg/watchyourlan:latest
    container_name: watchyourlan
    hostname: watchyourlan
    restart: unless-stopped
    network_mode: host
    env_file: .env
    volumes:
      - ./watchyourlan_data:/data
WYL_COMPOSE

    cat > .env << WYL_ENV
# ── General ───────────────────────────────────────────────────────────────────
TZ=$TZ_VAL

# ── WatchYourLAN ──────────────────────────────────────────────────────────────
# Network interface to scan (ARP scanning requires the physical interface)
IFACE=$SCAN_IFACE

# GUI bind address and port (network_mode: host — binds directly to the host)
GUIIP=0.0.0.0
GUIPORT=$GUI_PORT

# Web UI theme (darkly, cosmo, lumen, sandstone, etc.)
THEME=darkly
WYL_ENV

    chown -R "$ACTUAL_USER:$ACTUAL_USER" "$WYL_DIR"
    log_success "WatchYourLAN configured at $WYL_DIR"

    # WatchYourLAN uses network_mode: host, so Caddy container-name routing
    # can't reach it via caddy_net. Access is directly on host port $GUI_PORT.
    # If behind Caddy on the same host, configure manually with host IP:PORT.
    if [ -d "$DOCKER_DIR/caddy" ]; then
        echo ""
        log_info "Note: WatchYourLAN uses host networking (needed for ARP scanning)."
        log_info "It cannot join caddy_net. To put it behind Caddy, add this block manually:"
        echo ""
        echo "  yourdomain.com {"
        echo "      reverse_proxy <HOST_IP>:$GUI_PORT"
        echo "  }"
        echo ""
        echo "  where HOST_IP is this server's IP on the Docker bridge (usually 172.17.0.1)."
    fi

    write_readme "$WYL_DIR" << MD
# WatchYourLAN — network device tracker

Scans the network continuously for connected devices, tracks history,
and alerts on new or unknown devices joining the network.

## Access
- URL: http://localhost:$GUI_PORT  (or http://<server-ip>:$GUI_PORT from LAN)

## Scanning interface
Configured to scan: **$SCAN_IFACE**
Change \`IFACE\` in .env and restart if you need to scan a different interface.

## Network mode note
WatchYourLAN uses \`network_mode: host\` to see real ARP traffic.
This means it cannot be added to caddy_net for reverse proxy via container name.
To put it behind Caddy, use the host's IP directly in the Caddyfile:
\`reverse_proxy 172.17.0.1:$GUI_PORT\` (adjust IP to your Docker bridge gateway).

## Manage
\`\`\`bash
cd $WYL_DIR
docker compose up -d      # start
docker compose down       # stop
docker compose logs -f    # logs
docker compose pull && docker compose up -d   # update
\`\`\`
MD

    local START_WYL=""
    prompt_yn "Start WatchYourLAN now? (y/n):" "y" START_WYL
    if [ "$START_WYL" = "y" ] || [ "$START_WYL" = "Y" ]; then
        docker compose up -d \
            && log_success "WatchYourLAN started" \
            || log_warning "Failed to start — check: docker compose logs"
    fi

    echo "  Access at:  http://localhost:$GUI_PORT"
    echo "  Scanning:   interface $SCAN_IFACE"
    echo ""
}