ubuntu-post-install/services/gatus.sh

#!/bin/bash
# services/gatus.sh — Gatus status/uptime monitoring page.
# Part of the modular post-install system (sourced by setup.sh).
#
# Can also be run standalone on any machine:
#   sudo bash gatus.sh
# (Docker must already be installed when run standalone)
#
# Gatus polls endpoints (HTTP, TCP, DNS, ICMP) on a schedule and shows a
# clean status dashboard. Config is hot-reloaded from gatus_config/config.yaml.

# ── Standalone bootstrap ──────────────────────────────────────────────────────
# Detected when the script is executed directly rather than sourced by setup.sh.
# Sets up helpers and globals, then defers execution until after the function
# definition at the bottom of this file.
if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
    [[ "$(id -u)" == "0" ]] || { echo "Run with sudo: sudo bash $0"; exit 1; }

    _SELF_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
    _COMMON="$_SELF_DIR/../lib/common.sh"

    if [[ -f "$_COMMON" ]]; then
        # Full repo present — use the real helpers (picks up ~/docker/.config too)
        # shellcheck source=../lib/common.sh
        source "$_COMMON"
    else
        # One-off copy — inline minimal stubs so the script works without the repo
        log_info()    { echo -e "\033[0;34m[INFO]\033[0m $*"; }
        log_success() { echo -e "\033[0;32m[OK]\033[0m $*"; }
        log_warning() { echo -e "\033[1;33m[WARN]\033[0m $*"; }
        log_error()   { echo -e "\033[0;31m[ERROR]\033[0m $*" >&2; }

        require_docker() {
            command -v docker &>/dev/null || {
                log_error "Docker not found. Install it first:"
                log_error "  curl -fsSL https://get.docker.com | sudo sh"
                return 1
            }
            docker compose version &>/dev/null || {
                log_error "Docker Compose plugin missing:"
                log_error "  sudo apt-get install -y docker-compose-plugin"
                return 1
            }
        }

        ensure_docker_dir_ownership() {
            chown -R "$ACTUAL_USER:$ACTUAL_USER" "$@" 2>/dev/null || true
        }

        port_in_use() {
            local _port="$1" _proto="${2:-tcp}"
            local _flag="-tlnH"
            [ "$_proto" = "udp" ] && _flag="-ulnH"
            ss "$_flag" "sport = :${_port}" 2>/dev/null | grep -q .
        }

        find_free_port() {
            local _varname="$1" _port="$2" _proto="${3:-tcp}"
            while port_in_use "$_port" "$_proto"; do
                _port=$((_port + 1))
            done
            eval "$_varname='$_port'"
        }

        # Match common.sh's eval-based pattern so local vars in install_* are set correctly
        prompt_text() {
            local _q="$1" _def="$2" _var="$3" _r
            [[ "${UNATTENDED:-false}" == "true" ]] && { eval "$_var='$_def'"; return; }
            read -r -p "  $_q " _r
            eval "$_var='${_r:-$_def}'"
        }

        prompt_yn() {
            local _q="$1" _def="$2" _var="$3" _r
            [[ "${UNATTENDED:-false}" == "true" ]] && { eval "$_var='$_def'"; return; }
            read -r -p "  $_q " _r
            eval "$_var='${_r:-$_def}'"
        }

        configure_caddy_for_service() {
            local _name="$1" _upstream="$2" _subdomain="$3" _extra="${4:-}"
            local _caddy_dir="$DOCKER_DIR/caddy"
            local _caddyfile="$_caddy_dir/Caddyfile"
            local _display_port="${_upstream##*:}"

            # Determine mode: local Caddy, remote Caddy, or none
            local _mode="none"
            [[ -d "$_caddy_dir" ]] && _mode="local"
            [[ -n "${CADDY_REMOTE_HOST:-}" ]] && [[ "$_mode" != "local" ]] && _mode="remote"
            [[ "$_mode" == "none" ]] && {
                log_info "Access $_name directly on port $_display_port."
                return 0
            }

            echo ""
            local _do_caddy=""
            if [[ "$_mode" == "remote" ]]; then
                log_info "Remote Caddy configured (${CADDY_REMOTE_HOST})."
                log_info "A snippet file will be saved to ~/docker/caddy-snippets/."
            fi
            read -r -p "  Configure Caddy reverse proxy for $_name? [y/N]: " _do_caddy
            [[ "${_do_caddy,,}" == "y" ]] || {
                log_info "Skipping — access at: http://localhost:$_display_port"
                return 0
            }

            # Domain prompt — pre-fill from SITE_DOMAIN when available
            local _default_domain=""
            if [[ -n "${SITE_DOMAIN:-}" ]] && [[ "$SITE_DOMAIN" != "example.com" ]]; then
                _default_domain="${_subdomain}.${SITE_DOMAIN}"
                log_info "Default: $_default_domain"
            fi
            local _domain=""
            read -r -p "  Domain [${_default_domain:-required}]: " _domain
            _domain="${_domain:-$_default_domain}"
            [[ -n "$_domain" ]] || { log_warning "No domain entered — skipping Caddy."; return 0; }

            # Build upstream — remote Caddy uses host IP:port, not container name
            local _block_upstream="$_upstream"
            if [[ "$_mode" == "remote" ]]; then
                _block_upstream="${CADDY_REMOTE_HOST}:${_display_port}"
            fi

            local _site_block
            _site_block="$(cat << CBLOCK

# $_name
${_domain} {
    reverse_proxy ${_block_upstream}

    header {
        Strict-Transport-Security "max-age=31536000; includeSubDomains; preload"
        X-Content-Type-Options "nosniff"
        X-Frame-Options "SAMEORIGIN"
        Referrer-Policy "strict-origin-when-cross-origin"
    }

    log {
        output file /var/log/caddy/${_domain}.log
        format json
    }
${_extra}
}
CBLOCK
)"

            if [[ "$_mode" == "local" ]]; then
                if [[ -f "$_caddyfile" ]]; then
                    local _bk="$_caddy_dir/Caddyfile.backup.$(date +%Y%m%d-%H%M%S)"
                    cp "$_caddyfile" "$_bk"
                    log_info "Backed up Caddyfile to $(basename "$_bk")"
                else
                    touch "$_caddyfile"
                fi

                if grep -q "^${_domain}" "$_caddyfile" 2>/dev/null; then
                    log_warning "$_domain already in Caddyfile"
                    local _ow=""
                    read -r -p "  Overwrite? [y/N]: " _ow
                    [[ "${_ow,,}" == "y" ]] || { log_info "Keeping existing entry."; return 0; }
                    sed -i "/^${_domain}/,/^}/d" "$_caddyfile"
                fi

                printf '%s\n' "$_site_block" >> "$_caddyfile"
                log_success "Added $_domain to Caddyfile"
                docker exec caddy caddy fmt --overwrite /etc/caddy/Caddyfile 2>/dev/null || true
                if docker exec caddy caddy reload --config /etc/caddy/Caddyfile 2>/dev/null; then
                    log_success "$_name accessible at: https://$_domain"
                else
                    log_warning "Reload failed — check: docker logs caddy"
                    log_info "Manual reload: docker exec caddy caddy reload --config /etc/caddy/Caddyfile"
                fi
            else
                local _snippet_dir="$DOCKER_DIR/caddy-snippets"
                local _snippet_file="$_snippet_dir/${_subdomain}.caddy"
                mkdir -p "$_snippet_dir"
                printf '%s\n' "$_site_block" > "$_snippet_file"
                chown "$ACTUAL_USER:$ACTUAL_USER" "$_snippet_file" 2>/dev/null || true
                log_success "Snippet saved: $_snippet_file"
                log_info "Copy to Caddy machine:"
                log_info "  scp $_snippet_file caddy-host:~/caddy-snippets/"
                log_info "  rsync -av $_snippet_dir/ caddy-host:~/caddy-snippets/  (all at once)"
            fi
        }
        write_readme() {
            local _dir="$1"; shift
            mkdir -p "$_dir"
            cat > "$_dir/README.md"
        }
    fi

    # Globals — ACTUAL_USER/ACTUAL_HOME must come before DOCKER_DIR
    # ($HOME under sudo is /root, not the real user's home)
    ACTUAL_USER="${ACTUAL_USER:-${SUDO_USER:-$USER}}"
    ACTUAL_HOME="$(getent passwd "$ACTUAL_USER" 2>/dev/null | cut -d: -f6 || echo "${HOME:-/root}")"
    DOCKER_DIR="${DOCKER_DIR:-$ACTUAL_HOME/docker}"
    DRY_RUN="${DRY_RUN:-false}"
    UNATTENDED="${UNATTENDED:-false}"
    SITE_TZ="${SITE_TZ:-$(cat /etc/timezone 2>/dev/null || echo UTC)}"
    SITE_DOMAIN="${SITE_DOMAIN:-example.com}"
    SITE_CADDY_NET="${SITE_CADDY_NET:-caddy_net}"

    register_service() { :; }   # no-op — no wizard to register into
    _RUN_STANDALONE=1
fi
# ─────────────────────────────────────────────────────────────────────────────

register_service gatus utilities "Status & uptime monitoring page (Gatus)" 8086

install_gatus() {
    require_docker || return 1
    log_info "Installing Gatus..."
    local GATUS_DIR="$DOCKER_DIR/gatus"
    local WEB_PORT="8086"

    if [ "$DRY_RUN" = true ]; then
        echo "[DRY-RUN] Would create $GATUS_DIR (gatus_config/, gatus_data/)"
        echo "[DRY-RUN] Would deploy twinproduction/gatus:latest"
        echo "[DRY-RUN] Port 8086 published (auto-scanned for a free host port),"
        echo "[DRY-RUN] config at gatus_config/config.yaml"
        return 0
    fi

    # Scan for a free host port — a plain install shouldn't silently claim a
    # port another already-running service holds. See CLAUDE.md's "Port
    # collision avoidance" section.
    find_free_port WEB_PORT "$WEB_PORT"

    mkdir -p "$GATUS_DIR/gatus_config" "$GATUS_DIR/gatus_data"
    ensure_docker_dir_ownership "$GATUS_DIR"
    cd "$GATUS_DIR" || return 1

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

    # Mirrors configure_caddy_for_service's own mode resolution (lib/common.sh):
    # explicit CADDY_MODE from the site config wins, then a local ~/docker/caddy,
    # then the legacy CADDY_REMOTE_HOST var. Only "local" joins caddy_net — a
    # remote Caddy box can't resolve container names on this host's bridge
    # network anyway; it reaches this service via the host's published port.
    local _CADDY_MODE="${CADDY_MODE:-none}"
    [ "$_CADDY_MODE" = "none" ] && [ -d "$DOCKER_DIR/caddy" ] && _CADDY_MODE="local"
    [ "$_CADDY_MODE" = "none" ] && [ -n "${CADDY_REMOTE_HOST:-}" ] && _CADDY_MODE="remote"

    local _CADDY_NET_BLOCK=""
    local _CADDY_NET_SECTION=""
    if [ "$_CADDY_MODE" = "local" ]; then
        _CADDY_NET_BLOCK="    networks:
      - caddy_net
"
        _CADDY_NET_SECTION="
networks:
  caddy_net:
    external: true
    name: ${SITE_CADDY_NET:-caddy_net}
"
    fi

    cat > docker-compose.yml << GATUS_COMPOSE
name: gatus

services:
  gatus:
    image: twinproduction/gatus:latest
    container_name: gatus
    hostname: gatus
    restart: unless-stopped
    env_file: .env
    ports:
      - "${WEB_PORT}:8080"
    volumes:
      - ./gatus_config:/config
      - ./gatus_data:/data
${_CADDY_NET_BLOCK}${_CADDY_NET_SECTION}
GATUS_COMPOSE

    cat > .env << GATUS_ENV
TZ=$TZ_VAL
CADDY_NET=$SITE_CADDY_NET
GATUS_ENV

    # Write a sample config if none exists
    if [ ! -f gatus_config/config.yaml ]; then
        cat > gatus_config/config.yaml << 'GATUS_CFG'
# Gatus configuration — docs: https://github.com/TwiN/gatus
#
# Add or remove endpoints below. Config is hot-reloaded on changes.
# Alert types: ntfy, slack, discord, email, telegram, and more.

storage:
  type: sqlite
  path: /data/gatus.db

ui:
  title: "Status"
  header: "Services"

# ── Endpoints ─────────────────────────────────────────────────────────────────
endpoints:
  - name: Google DNS
    group: external
    url: "8.8.8.8"
    dns:
      query-name: "google.com"
      query-type: "A"
    interval: 5m
    conditions:
      - "[DNS_RCODE] == NOERROR"

  - name: Example HTTPS
    group: external
    url: "https://example.com"
    interval: 5m
    conditions:
      - "[STATUS] == 200"
      - "[RESPONSE_TIME] < 3000"
      - "[CERTIFICATE_EXPIRATION] > 48h"

  # ── Add your services below ────────────────────────────────────────────────
  # - name: Mealie
  #   group: homelab
  #   url: "http://mealie:9000/api/app/about"
  #   interval: 1m
  #   conditions:
  #     - "[STATUS] == 200"
  #     - "[RESPONSE_TIME] < 500"
  #
  # - name: Portainer
  #   group: homelab
  #   url: "https://portainer:9443"
  #   interval: 1m
  #   conditions:
  #     - "[STATUS] == 200"
  #   client:
  #     insecure: true
GATUS_CFG
    fi

    chown -R "$ACTUAL_USER:$ACTUAL_USER" "$GATUS_DIR"
    log_success "Gatus configured at $GATUS_DIR"

    configure_caddy_for_service "Gatus" "gatus:8080" "status"

    write_readme "$GATUS_DIR" << MD
# Gatus — status & uptime monitoring

Clean, self-hosted status page. Polls HTTP, TCP, DNS, and ICMP endpoints.

## Access
- URL: http://localhost:${WEB_PORT}

## Configuration
Edit \`gatus_config/config.yaml\` — changes are **hot-reloaded** without restarting.

Key concepts:
- \`endpoints:\` — what to check (HTTP, TCP, DNS, ICMP)
- \`interval:\` — how often (e.g. 1m, 5m)
- \`conditions:\` — pass/fail rules ([STATUS], [RESPONSE_TIME], etc.)
- \`alerts:\` — notify via ntfy, Slack, Discord, email, etc.

Full docs: https://github.com/TwiN/gatus

## Manage
\`\`\`bash
cd $GATUS_DIR
docker compose up -d      # start
docker compose down       # stop
docker compose logs -f    # logs (check config errors here)
docker compose pull && docker compose up -d   # update
\`\`\`
MD

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

    echo "  Access at:  http://localhost:${WEB_PORT}"
    echo "  Config:     $GATUS_DIR/gatus_config/config.yaml (hot-reloaded)"
    echo ""
}

# Run immediately when executed directly (deferred until after function definition)
[[ "${_RUN_STANDALONE:-0}" == 1 ]] && install_gatus