ubuntu-post-install/CLAUDE.md

CLAUDE.md — ubuntu-post-install contributor guide

Context for adding or modifying services. Read this before touching any service file so the result matches what's already here.

How the system works

setup.sh sources lib/common.sh then globs every services/*.sh file. Each service file self-registers and defines its install function. Nothing in setup.sh needs to change when you add a service — just add the file.

The wizard groups services by category (from register_service), shows a checklist per group, and calls install_<name>() for each selected item. --list, --dry-run, and --unattended all work automatically.

Adding a service — the three-step rule

1. Create services/<name>.sh (kebab-case filename)
2. Call register_service at the top of the file
3. Define install_<name>() (hyphens → underscores in function name)

That's it. The menu picks it up on the next run.

Minimal Docker service template

#!/bin/bash
# services/my-tool.sh — One-line description.
# Part of the modular post-install system (sourced by setup.sh).

register_service my-tool utilities "What it does (My Tool)" 8080

install_my_tool() {
    require_docker || return 1

    local DIR="$DOCKER_DIR/my-tool"

    if [ "$DRY_RUN" = true ]; then
        echo "[DRY-RUN] Would create $DIR with docker-compose.yml"
        return 0
    fi

    mkdir -p "$DIR"
    ensure_docker_dir_ownership "$DIR"
    cd "$DIR" || return 1

    cat > docker-compose.yml << 'EOF'
name: my-tool
services:
  my-tool:
    image: vendor/my-tool:latest
    container_name: my-tool
    restart: unless-stopped
    ports:
      - "8080:8080"
    volumes:
      - ./data:/data
EOF

    configure_caddy_for_service "My Tool" "8080" "my-tool"

    write_readme "$DIR" << 'MD'
# My Tool
Brief description.

## Manage
```bash
docker compose up -d
docker compose down
docker compose logs -f
docker compose pull && docker compose up -d

MD

local START=""
prompt_yn "Start My Tool now? (y/n):" "y" START
if [ "$START" = "y" ] || [ "$START" = "Y" ]; then
    docker compose up -d \
        && log_success "My Tool started" \
        || log_warning "Start failed — check: docker compose logs"
fi

}

## register_service signature

```bash
register_service <name> <group> "<description>" [port]

• name — kebab-case, matches the filename and the install_ function
• group — one of the categories below; determines which menu it appears in
• description — shown in --list and the menu checklist
• port — optional; informational only (not used by the framework)

Available globals

Variable	Value
DOCKER_DIR	~/docker — parent for all Docker service directories
ACTUAL_USER	The non-root user that invoked sudo
ACTUAL_HOME	Home directory of ACTUAL_USER
SITE_TZ	Timezone from site config, e.g. America/New_York
SITE_DOMAIN	Base domain from site config, e.g. example.com
SITE_CADDY_NET	Docker network name for Caddy (default: caddy_net)
DRY_RUN	true/false — set by --dry-run flag
UNATTENDED	true/false — set by --unattended flag

Available helpers (lib/common.sh)

Logging

log_info    "message"   # blue   [INFO]
log_success "message"   # green  [OK]
log_warning "message"   # yellow [WARN]
log_error   "message"   # red    [ERROR]

Prompts — honor UNATTENDED automatically

prompt_yn   "Question? (y/n):" "default_y_or_n" VARNAME
prompt_text "Question? [default]:" "default" VARNAME

When UNATTENDED=true both functions skip the prompt and use the default.

Pre-flight

require_root    # exits with an error if not running as root
require_docker  # installs Docker CE + Compose plugin if missing, then returns

Execution and ownership

run_cmd COMMAND [args...]           # no-ops in DRY_RUN, executes otherwise
ensure_docker_dir_ownership DIR...  # chown -R ACTUAL_USER:ACTUAL_USER (skips in DRY_RUN)
generate_password [length]          # alphanumeric random string, default 32 chars
pip_user_install PACKAGE...         # pip3 --user with --break-system-packages on 24.04+

Caddy reverse proxy

configure_caddy_for_service "Display Name" "PORT" "default-subdomain" ["extra-block"]

Prompts the user for a domain, appends a site block to the Caddyfile, and reloads Caddy. No-ops silently if Caddy isn't installed. The fourth argument is an optional string inserted verbatim inside the Caddy site block (use it for import authelia or custom matchers).

README generation

write_readme "$DIR" << 'MD'
# Title
Content
MD

Writes $DIR/README.md (creates the directory if needed). No-ops in DRY_RUN. Every Docker service should call this so ~/docker/<name>/README.md is self-documenting on the deployed box.

Categories

Group	Purpose
base	CLI packages installed on every box
homelab	Core infrastructure — reverse proxy, auth, intrusion prevention
utilities	Self-hosted web apps — budget, DNS, files, monitoring, VPN, etc.
media	Media servers, photo backup, disc ripping
cameras	NVR and camera tooling (Frigate)
gaming	Game servers, cloud gaming (Wolf), emulation
extras	Non-Docker tools and scripts
backup	Backup solutions

Non-Docker services

Not everything is a container. For apt-based or git-clone–based services, skip require_docker and the Docker helpers. See services/base.sh (apt packages + Charm repo) and services/crowdsec.sh (official apt repo) as reference patterns.

For non-Docker services the default is_installed check in setup.sh looks for $DOCKER_DIR/$name, which won't exist. Add a case to the is_installed() function in setup.sh so the [installed] marker appears correctly in the menu:

# In setup.sh → is_installed()
my-tool) command -v my-tool >/dev/null 2>&1 ;;

Docker services use the default case and don't need an entry.

DRY_RUN convention

Every install_* function must check $DRY_RUN before touching the filesystem, installing packages, or starting containers. The pattern is:

if [ "$DRY_RUN" = true ]; then
    echo "[DRY-RUN] Would do X"
    echo "[DRY-RUN] Would do Y"
    return 0
fi

Put the check early — after any pure-display output (banners, info text) but before the first write.

.env files and secrets

Generate passwords with generate_password (never hardcode them). Write secrets to .env files in the service directory, owned by ACTUAL_USER, permissions 600. Document every variable with a comment in the .env heredoc so the user knows what to change later.

Caddy network wiring

Services that need to reach Caddy (or each other) over Docker networking should join the $SITE_CADDY_NET network. Add to docker-compose.yml:

networks:
  caddy_net:
    external: true
    name: ${CADDY_NET:-caddy_net}

And read the network name from .env using CADDY_NET=$SITE_CADDY_NET.