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.

Also update the Services table in README.md — add the service name to the appropriate group row so the README stays current.

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
prompt_reinstall_mode VARNAME   # sets VARNAME to: update | fresh | cancel

When UNATTENDED=true all three skip the prompt; prompt_yn/prompt_text use their given default, prompt_reinstall_mode always resolves to cancel. See Update vs. fresh reinstall on rerun below for how to use the latter.

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).

The function places that block before reverse_proxy in the generated site block — don't reorder this. forward_auth (what import authelia expands to) is the same directive family as reverse_proxy internally, and Caddy doesn't reorder repeats of the same directive within a block; it runs them in the order they're written. reverse_proxy written first would handle and terminate every request immediately, making an auth check written after it dead code that never runs — full bypass regardless of what the auth server's own access-control rules say. Confirmed live: this was the actual cause of a "Caddy proxies fine but Authelia never prompts for login" bug, on a site block that otherwise looked completely correct. If a service builds its own site block instead of using this helper (e.g. services/asterisk-digital-ocean.sh does, deliberately, see its own comment for why), put its auth block first there too.

forward_auth to a remote Authelia over a scheme-qualified URL needs explicit header_up pins. A bare forward_auth authelia:9091 (Authelia on the same Docker network, one hop) is fine relying on Caddy's default X-Forwarded-* headers. But forward_auth https://auth.example.com { ... } (Authelia on a different machine, reached over its own public domain+TLS — see services/asterisk-digital-ocean.sh's remote-Authelia prompt) is a second Caddy hop: Caddy rewrites the outgoing request's Host header to auth.example.com so the remote Caddy can route/SNI-match it, and without an override X-Forwarded-Host picks up that rewritten value instead of the original site's host. Confirmed live: Authelia evaluated every protected domain as if the request were for auth.example.com itself (which typically has policy: bypass in access_control.rules so its own login portal isn't gated behind itself) — so every domain behind the remote instance silently passed through with no 2FA prompt, regardless of that domain's own policy. Fix: pin the forwarded headers to the original request explicitly instead of trusting Caddy's default derivation:

forward_auth https://auth.example.com {
    uri /api/authz/forward-auth
    copy_headers Remote-User Remote-Groups Remote-Name Remote-Email
    header_up X-Forwarded-Method {method}
    header_up X-Forwarded-Proto {scheme}
    header_up X-Forwarded-Host {host}
    header_up X-Forwarded-Uri {uri}
}

This only affects the remote-Authelia path — same-machine authelia:9091 snippets (services/authelia.sh) are a single hop and don't need it.

Sets two out-params (not local — read them after the call returns) so the caller can tell whether Caddy actually ended up fronting the service:

CADDY_SERVICE_CONFIGURED   # true/false
CADDY_SERVICE_MODE         # "local" or "remote" (only meaningful if configured)

Use this to skip opening a host firewall port for a service Caddy already fronts locally (it reaches the service over host.docker.internal, not the network) — but still open it when CADDY_SERVICE_MODE is "remote", since a remote Caddy machine needs to reach this host over the network instead. See services/asterisk.sh and services/asterisk-digital-ocean.sh for the reference pattern: call configure_caddy_for_service before building firewall rules, not after, so the decision is known in time.

UFW enable

ensure_ufw_enabled

Call this after your service has already added its own ufw allow rules — it only flips UFW from inactive to active, it doesn't add rules for you. No-ops if UFW is already active or not installed. Always allows SSH first (reading the real port from sshd_config in case it's non-default) before enabling, so this can't lock out the session running the installer.

Closing a port to the internet without also closing it to Caddy

ufw_allow_from_caddy_net PORT [PROTO]   # PROTO defaults to tcp

When CADDY_SERVICE_MODE is "local" (see above) and you ufw delete allow a port because Caddy fronts it now, don't stop there — UFW rules apply to all interfaces unless scoped, and Caddy's own request to host.docker.internal:PORT is ordinary INPUT-chain traffic arriving over the caddy_net bridge, not the public internet. A bare ufw delete allow blocks that too and silently breaks the service (confirmed live: closing the web admin port outright took Caddy down with it). Call ufw_allow_from_caddy_net right after the delete to re-open the port scoped to just caddy_net's subnet — reachable from Caddy, not from the internet. See services/asterisk-digital-ocean.sh and services/asterisk.sh for the pattern.

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

Authelia SSO — which services need it

Some services have their own login screens; others have none and need Caddy to gate them via Authelia.

Running more than one Authelia instance (e.g. one per machine). services/authelia.sh runs standalone on any box (sudo bash authelia.sh, same pattern as crowdsec.sh) and asterisk-digital-ocean.sh already auto-detects a local install (if [ -d "$DOCKER_DIR/authelia" ]), switching from the remote-Authelia forward_auth flow to the local import authelia snippet automatically — so a second, fully independent instance on another machine (e.g. a droplet, for resilience if the first machine goes down) works with no code changes.

The one real constraint: Authelia's session cookie is scoped to AUTHELIA_DOMAIN (the apex domain entered at install time) with includeSubDomains-style matching, and the portal itself lives at auth.${AUTHELIA_DOMAIN}. Two independent instances must not share the same AUTHELIA_DOMAIN. If they did, both would try to claim the same auth.<domain> hostname (DNS can only point that at one machine) and the same cookie scope with completely separate session stores — users bouncing between subdomains fronted by different instances would see confusing repeated logins as each instance's cookie gets overwritten/rejected by the other's. Give each instance either a genuinely separate apex domain, or a distinct subdomain tree the other instance doesn't also claim.

Has built-in auth — no Authelia needed: emby, jellyfin, audiobookshelf, immich, mealie, actualbudget, homeassistant, portainer, meshcentral, traccar, uptimekuma, filebrowser, wg-easy, ntfy (configurable)

No built-in auth — should be protected: magicmirror, wolf-pair, js99er, sky-cam

For services without built-in auth, prompt the user before calling configure_caddy_for_service and pass import authelia as the extra block if Authelia is installed and the user wants SSO protection:

local EXTRA_BLOCK=""
if [ -d "$DOCKER_DIR/authelia" ]; then
    local _use_auth=""
    prompt_yn "Protect MagicMirror with Authelia SSO? (y/n):" "y" _use_auth
    [[ "$_use_auth" =~ ^[Yy]$ ]] && EXTRA_BLOCK="    import authelia"
fi
configure_caddy_for_service "MagicMirror" "8081" "mirror" "$EXTRA_BLOCK"

Authelia "stay logged in" / kiosk mode: Edit ~/docker/authelia/config/configuration.yml and set a long remember_me_duration. Users then check "Remember me" once on login and the session persists through reboots (Redis stores the session in a volume):

session:
  secret: 'your-existing-secret'
  remember_me_duration: 1y     # add or update this line
  expiration: 1h
  inactivity: 5m
  cookies:
    - domain: 'example.com'
      authelia_url: 'https://auth.example.com'

After editing: docker compose -f ~/docker/authelia/docker-compose.yml restart

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.

Update vs. fresh reinstall on rerun

Every service should detect an existing install at the top of its install_<name>() — after the DRY_RUN check, before any prompts — and offer prompt_reinstall_mode instead of silently re-running every prompt (domain, secrets, firewall, Authelia, extras...) from scratch. What counts as "already installed" is service-specific: usually docker-compose.yml and .env both existing in the service's $DOCKER_DIR/<name> directory.

if [[ -f "$DIR/docker-compose.yml" && -f "$DIR/.env" ]]; then
    local MODE=""
    prompt_reinstall_mode MODE
    case "$MODE" in
        update)
            # Refresh vendor files / config templates, rebuild, done.
            # Do NOT touch .env, firewall rules, or Caddy/Authelia config.
            ...
            return 0
            ;;
        cancel)
            log_info "Leaving the existing install as-is."
            return 0
            ;;
        fresh) ;;  # fall through to the full install flow below
    esac
fi

update should be genuinely non-destructive: refresh whatever the service vendors or templates (Docker image sources, config templates, docker-compose.yml) and rebuild/restart, but never touch .env, firewall rules, or reverse-proxy/SSO config that's already in place. If the vendor-copy or docker-compose.yml-generation logic is more than a few lines, factor it into a helper function so the fresh-install path and the update path share one copy instead of drifting apart — see _asterisk_do_refresh_vendor_files/_asterisk_do_write_compose in services/asterisk-digital-ocean.sh (and their _asterisk_* counterparts in services/asterisk.sh) for the reference pattern.

cancel must leave the install completely untouched — it's the default for a reason (a stray Enter on a service you're just checking on shouldn't trigger anything). fresh runs the exact same flow a first-time install would, prompts included.

.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.

external: true means this service expects the network to already exist — it doesn't create it. require_docker creates it for you (via ensure_caddy_network in lib/common.sh) the first time any service calls it, so as long as your install_<name>() calls require_docker before docker compose up (it always should), the network is guaranteed to exist regardless of whether Caddy itself has been installed yet.

network_mode: host services (e.g. asterisk/asterisk-digital-ocean) don't join caddy_net at all — Caddy reaching them (or anything else on the host network) needs host.docker.internal:PORT in the Caddyfile, not localhost:PORT or a container name. Caddy's own compose file (services/caddy.sh) sets extra_hosts: host.docker.internal:host-gateway so that hostname resolves; configure_caddy_for_service's bare-port upstream case already does this for you — don't hand-roll localhost:PORT in a Caddy site block.