feat(labelprint): 4x6 label print proxy on a Raspberry Pi

A Pi 3B+ (stickah.local) shares a Phomemo PM246 to the LAN as a plain CUPS queue, so any machine can print 4x6 labels -- fulfillr-site's shipping labels in particular -- without installing the vendor driver, which is x86-64 only. The role builds the TSPL CUPS driver from source instead. It is Debian, not Fedora, so it lives in its own inventory and playbook (make deploy-labelprint / check-labelprint) and the home.debyl.io roles can never run against it. make bootfs renders its cloud-init first-boot files onto a freshly imaged SD card from the same templates the role uses. The Wi-Fi credentials for the home and rescue networks are in the vault. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-13 23:14:45 -04:00
parent be0d02b938
commit 6cd4d56de1
26 changed files with 1593 additions and 1 deletions
@@ -14,6 +14,8 @@ This is a home infrastructure deployment repository using Ansible for automated
 - `make deploy TAGS=sometag` - Deploy only specific tagged tasks
 - `make deploy TARGET=specific-host` - Deploy to specific host instead of all
 - `make check` - Run deployment in dry-run mode showing potential changes
 - `make deploy-labelprint` / `make check-labelprint` - Deploy (or dry-run) the label print proxy Pi. Separate inventory and playbook from the home server - see `ansible/roles/labelprint/README.md`
 - `make bootfs BOOTFS=/Volumes/bootfs` - Render the label print proxy's cloud-init first-boot files onto a freshly imaged SD card
 - `make vault` - Edit encrypted Ansible vault file
 - `make list-tags` - List all available Ansible tags
 - `make list-tasks` - List all Ansible tasks
@@ -33,13 +35,16 @@ The project uses Python virtualenv for dependency management:
 ansible/
 ├── deploy.yml          # Main playbook entry point (imports deploy_home.yml)
 ├── deploy_home.yml     # Core playbook with role definitions
 ├── deploy_labelprint.yml  # Label print proxy Pi (separate host, Debian)
 ├── inventories/home/   # Inventory configuration
 ├── inventories/labelprint/  # Label print proxy inventory
 ├── roles/              # Ansible roles organized by function
 │   ├── common/        # Base system configuration
 │   ├── git/           # Git repository management
 │   ├── podman/        # Container orchestration
 │   ├── ssl/           # Legacy SSL management (deprecated - Caddy handles certificates automatically)
 │   ├── github-actions/# CI/CD runner setup
 │   ├── labelprint/    # 4x6 label print proxy (Raspberry Pi, CUPS/TSPL)
 │   └── pihole/        # DNS filtering
 └── vars/
    └── vault.yml      # Encrypted secrets
@@ -96,13 +101,27 @@ Tasks are tagged by service/component for selective deployment:
 ## Target Environment
- Single target host: `home.debyl.io`
+- Primary target host: `home.debyl.io`
 - OS: Fedora (ansible_user: fedora)
 - Container runtime: Podman
 - Web server: Caddy with automatic HTTPS and built-in security (replaced nginx + ModSecurity)
 - All services accessible via HTTPS with automatic certificate renewal
 - ~~CI/CD: Drone CI infrastructure completely decommissioned~~
 ### Label print proxy
 - Second target host: `stickah.local` (Raspberry Pi 3B+, Raspberry Pi OS 64-bit,
  apt not dnf) with a Phomemo PM246 4x6 label printer on USB
 - Deployed only via `make deploy-labelprint` - it is in its own inventory so the
  Fedora roles can never run against it
 - The SD card image is written by hand with rpi-imager, but its cloud-init files
  come from `make bootfs`, rendered from the same templates the role uses
 - Login is `stickah` / `stickah` with SSH key auth preferred; password auth is a
  deliberate LAN-only fallback so the box is never unreachable
 - LAN-only (192.168.1.0/24), discovered over mDNS, no DNS record
 - Falls back to its own rescue Wi-Fi AP at 192.168.4.1 when the home SSID is
  unreachable
 ### Remote SSH Commands for Service Users
 The `podman` user (and other service users) have `/bin/nologin` as their shell. To run commands as these users via SSH:
@@ -21,6 +21,9 @@ VAULT_FILE=ansible/vars/vault.yml
 # Variables
 ANSIBLE_INVENTORY=ansible/inventories/home/hosts.yml
 # The label print proxy is a separate inventory and playbook: it is Debian, not
 # Fedora, and shares none of the roles home.debyl.io runs.
 ANSIBLE_INVENTORY_LABELPRINT=ansible/inventories/labelprint/hosts.yml
 #SSH_KEY=${HOME}/.ssh/id_rsa_home_ansible
 # Default to all ansible tags to run (passed via 'make deploy TAGS=sometag')
@@ -29,6 +32,9 @@ SKIP_TAGS?=none
 TARGET?=all
 EXTRA_VARS?=
 # Mounted boot partition of the label print proxy's SD card (see `make bootfs`)
 BOOTFS?=/Volumes/bootfs
 ${VENV}:
 	python3 -m venv ${VENV}
 	${VENV_BIN}/python3 -m pip install --upgrade pip
@@ -55,6 +61,19 @@ SKIP_FILE=./.lint-vars.sh
 deploy: ${ANSIBLE} ${VAULT_FILE}
 	${ANSIBLE} --diff -t ${TAGS} --skip-tags ${SKIP_TAGS} -i ${ANSIBLE_INVENTORY} -l ${TARGET} --vault-password-file ${VAULT_PASS_FILE} $(if ${EXTRA_VARS},-e "${EXTRA_VARS}") ansible/deploy.yml
 # Writes the Pi's cloud-init first-boot files onto a freshly imaged SD card.
 bootfs: ${ANSIBLE} ${VAULT_FILE}
 	${ANSIBLE} --diff -i ${ANSIBLE_INVENTORY_LABELPRINT} --vault-password-file ${VAULT_PASS_FILE} -e "bootfs=${BOOTFS}" ansible/bootfs.yml
 # Label print proxy (stickah.local). Override the address when the Pi has
 # fallen back to its rescue AP:
 #   make deploy-labelprint EXTRA_VARS="ansible_host=192.168.4.1"
 deploy-labelprint: ${ANSIBLE} ${VAULT_FILE}
 	${ANSIBLE} --diff -t ${TAGS} --skip-tags ${SKIP_TAGS} -i ${ANSIBLE_INVENTORY_LABELPRINT} -l ${TARGET} --vault-password-file ${VAULT_PASS_FILE} $(if ${EXTRA_VARS},-e "${EXTRA_VARS}") ansible/deploy_labelprint.yml
 check-labelprint: ${ANSIBLE} ${VAULT_FILE}
 	${ANSIBLE} --check --diff -t ${TAGS} --skip-tags ${SKIP_TAGS} -i ${ANSIBLE_INVENTORY_LABELPRINT} -l ${TARGET} --vault-password-file ${VAULT_PASS_FILE} $(if ${EXTRA_VARS},-e "${EXTRA_VARS}") ansible/deploy_labelprint.yml
 list-tags: ${ANSIBLE} ${VAULT_FILE}
 	${ANSIBLE} --list-tags -i ${ANSIBLE_INVENTORY} -l ${TARGET} --vault-password-file ${VAULT_PASS_FILE} ansible/deploy.yml
@@ -0,0 +1,106 @@
 ---
 # Renders the Raspberry Pi's cloud-init first-boot files onto a freshly written
 # SD card's boot partition:
 #
 #   make bootfs BOOTFS=/Volumes/bootfs
 #
 # The image itself is still built by hand with rpi-imager -- this only writes
 # the two cloud-init files onto it. Everything it writes comes from the same
 # templates roles/labelprint uses, so the Pi boots with its Wi-Fi profiles and
 # rescue access point already in place, and the first deploy has nothing to
 # correct.
 #
 # The rendered files contain the Wi-Fi PSKs in the clear, as any Pi Wi-Fi setup
 # does. They land on the SD card, never in this repo.
 - hosts: localhost
  gather_facts: false
  connection: local
  vars_files:
    - vars/vault.yml
    - roles/labelprint/defaults/main.yml
  tasks:
    - name: check that BOOTFS points at a Raspberry Pi boot partition
      ansible.builtin.stat:
        path: "{{ bootfs }}/config.txt"
      register: labelprint_bootfs_check
      tags: bootfs
    - name: refuse to write to anything else
      ansible.builtin.assert:
        that: labelprint_bootfs_check.stat.exists
        fail_msg: >-
          {{ bootfs }} has no config.txt, so it is not a Raspberry Pi boot
          partition. Write the image with rpi-imager first, then re-run with
          BOOTFS pointing at the mounted boot volume.
      tags: bootfs
    - name: look for files rpi-imager already wrote
      ansible.builtin.stat:
        path: "{{ bootfs }}/{{ item }}"
      register: labelprint_bootfs_existing
      loop:
        - user-data
        - network-config
        - cmdline.txt
      tags: bootfs
    # Keeps whatever rpi-imager put there, so a bad render can be undone by hand
    # without reflashing. force:false means the first run's backup is the one
    # that survives -- a second run must not overwrite it with our own output.
    - name: back up the files rpi-imager wrote
      ansible.builtin.copy:
        src: "{{ bootfs }}/{{ item.item }}"
        dest: "{{ bootfs }}/{{ item.item }}.rpi-imager.bak"
        mode: "0644"
        force: false
      loop: "{{ labelprint_bootfs_existing.results }}"
      loop_control:
        label: "{{ item.item }}"
      when: item.stat.exists
      tags: bootfs
    - name: render the cloud-init files
      ansible.builtin.template:
        src: "roles/labelprint/templates/bootfs/{{ item }}.j2"
        dest: "{{ bootfs }}/{{ item }}"
        mode: "0644"
      loop:
        - user-data
        - network-config
      tags: bootfs
    - name: hash the rendered user-data
      ansible.builtin.stat:
        path: "{{ bootfs }}/user-data"
        checksum_algorithm: sha1
      register: labelprint_user_data_stat
      tags: bootfs
    - name: stamp the instance id with that hash
      ansible.builtin.template:
        src: roles/labelprint/templates/bootfs/meta-data.j2
        dest: "{{ bootfs }}/meta-data"
        mode: "0644"
      vars:
        labelprint_user_data_id: "{{ labelprint_user_data_stat.stat.checksum[:12] }}"
      tags: bootfs
    # rpi-imager writes `ds=nocloud;i=<id>` onto the kernel command line, and
    # that id outranks the one in meta-data. Leave it alone and a card that has
    # booted even once is seen by cloud-init as the same instance forever: it
    # skips users, write_files and runcmd, silently, and the only symptom is a
    # Pi that came up with none of this applied. Both places have to agree.
    - name: pin the same instance id on the kernel command line
      ansible.builtin.replace:
        path: "{{ bootfs }}/cmdline.txt"
        regexp: '(ds=nocloud[^\s]*?);i=[^\s]+'
        replace: '\1;i={{ labelprint_hostname }}-{{ labelprint_user_data_stat.stat.checksum[:12] }}'
      tags: bootfs
    - name: what to do next
      ansible.builtin.debug:
        msg:
          - "Wrote user-data, network-config, meta-data and cmdline.txt to {{ bootfs }}."
          - "Instance id is {{ labelprint_hostname }}-{{ labelprint_user_data_stat.stat.checksum[:12] }}; the Pi re-applies this config whenever it changes."
          - "Eject the volume, boot the Pi, then: make deploy-labelprint"
      tags: bootfs
@@ -0,0 +1,14 @@
 ---
 # Label print proxy (Raspberry Pi 3B+, Raspberry Pi OS trixie).
 #
 # The Pi image itself is built by hand with rpi-imager and written to the SD
 # card outside of Ansible -- see roles/labelprint/README.md for what that image
 # has to contain. Everything from first boot onwards lives in the labelprint
 # role: the print driver, the CUPS queue, security updates, and the Wi-Fi
 # rescue access point.
 - hosts: labelprint
  vars_files:
    - vars/vault.yml
  roles:
    - role: labelprint
      tags: labelprint
@@ -0,0 +1,16 @@
 ---
 # The 4x6 label print proxy: a Raspberry Pi 3B+ with the Phomemo PM246 on USB,
 # shared to the LAN over IPP/AirPrint. Deliberately a separate inventory from
 # inventories/home: this host is Debian/apt and shares none of the Fedora roles
 # that home.debyl.io runs, so `make deploy` can never reach it by accident.
 #
 # Reached by mDNS (avahi on the Pi, Bonjour/UDM Pro on the LAN) rather than by a
 # DNS record. If the Pi has fallen back to its rescue access point, it is not on
 # the LAN at all -- join the rescue SSID and deploy against 192.168.4.1 instead:
 #
 #   make deploy-labelprint EXTRA_VARS="ansible_host=192.168.4.1"
 labelprint:
  hosts:
    stickah.local:
      ansible_user: stickah
      ansible_python_interpreter: /usr/bin/python3
@@ -0,0 +1,162 @@
 # labelprint — 4x6 label print proxy
 A Raspberry Pi 3B+ (`stickah.local`) with a **Phomemo PM246** on USB, shared to
 the LAN so any Mac, Windows or Linux machine can print 4x6 labels without
 installing a printer driver. Built for
 [`fulfillr-site`](../../../../debyltech/fulfillr-site), which prints shipping
 labels straight out of the browser, but the queue is a plain 4x6 label printer
 and anything can use it.
 Deployed on its own:
 ```
 make deploy-labelprint
 make check-labelprint            # dry run
 make deploy-labelprint TAGS=cups # just the queue
 ```
 ## Why not the Phomemo driver
 The vendor driver that runs on `yoga` installs
 `/usr/lib/cups/filter/rastertolabeltspl`, and that file is an **x86-64 ELF**.
 There is no ARM build, so none of it can be reused on the Pi.
 The PM246 speaks TSPL over USB, so this role builds
 [RunTheWall/tspl-cups-driver](https://github.com/RunTheWall/tspl-cups-driver)
 (MIT) from a pinned commit instead: a CUPS raster filter, a backend and a PPD,
 about a minute of compiling on the Pi. Pinned to a commit rather than installed
 from the project's apt repo so that a version bump is a reviewed change in this
 repo, and so the Pi carries no third-party signing key.
 The PM246's USB id is not in the driver's auto-detect list. `tspl://auto` is
 tried first; if the queue cannot find the printer, read the id off the Pi and
 pin it — see `labelprint_device_uri` in [defaults/main.yml](defaults/main.yml).
 ## The image
 The SD card image is built by hand, but the cloud-init files on it are not:
 `make bootfs` renders them from the same templates the role uses, so the Pi
 boots with its Wi-Fi profiles, its rescue access point and its login already in
 place. Nothing here needs the printer driver — that is Ansible's job.
 1. **Write the image** with rpi-imager: **Raspberry Pi OS (64-bit)**, Bookworm or
   newer, so NetworkManager is the network stack. Verified against the
   `2026-06-18` pi-gen build. Skip the customisation screen entirely — anything
   set there is about to be overwritten.
 2. **Render the boot files** onto the mounted boot partition:
   ```
   make bootfs                        # defaults to /Volumes/bootfs
   make bootfs BOOTFS=/path/to/boot
   ```
   It refuses to write anywhere without a `config.txt`, and keeps whatever
   rpi-imager wrote as `*.rpi-imager.bak`.
 3. **Eject**, boot the Pi, and give cloud-init a couple of minutes.
 4. `make deploy-labelprint`.
 `make bootfs` is safe to re-run. The instance id is a hash of the rendered
 `user-data`, so an unchanged render leaves the card alone, and a changed one
 makes the Pi re-apply it on the next boot.
 That id is written in **two** places, and they have to agree: `meta-data`, and
 the `ds=nocloud;i=<id>` token rpi-imager puts on the kernel command line in
 `cmdline.txt`. The command line wins. Leave rpi-imager's id there and a card
 that has booted even once looks like the same instance to cloud-init forever —
 it skips `users`, `write_files` and `runcmd` without a word, and the only
 symptom is a Pi that came up with none of this applied. `make bootfs` rewrites
 both.
 To force a re-apply on a Pi that is already running, without pulling the card:
 ```
 sudo sed -i 's/;i=[^ ]*/;i=<new-id>/' /boot/firmware/cmdline.txt
 sudo cloud-init clean --logs
 sudo reboot
 ```
 ### Getting in
 - `ssh stickah@stickah.local` — your `~/.ssh/id_ed25519.pub` is installed, and
  that is what Ansible uses.
 - Password auth is **on**, with the password `stickah`. It is deliberately
  trivial and deliberately not hashed: this is the fallback for a Pi that will
  not take the key — reflashed card, someone else's laptop, standing at the
  bench — and port 22 is reachable only from the LAN or from the rescue AP,
  which has a real WPA2 password of its own. If that trade stops being the right
  one, `labelprint_user_password` in [defaults/main.yml](defaults/main.yml) is
  the only thing to change.
 ## Wi-Fi and the rescue AP
 Normally the Pi is a station on the home SSID. When that network is
 unreachable — the password changed, the router died, the Pi moved — the
 `wifi-rescue` watchdog brings up an access point so there is still a way in:
 - Join the rescue SSID (both it and its password are in the vault).
 - The Pi is at **192.168.4.1**: `ssh pi@192.168.4.1`, or print directly to
  `ipp://192.168.4.1:631/printers/labels`.
 - Deploy to it there with
  `make deploy-labelprint EXTRA_VARS="ansible_host=192.168.4.1"`.
 The Pi also keeps the Wi-Fi profile netplan rendered from the image's original
 `network-config`, at a lower autoconnect priority than `home-wifi`. It is a
 deliberate fallback: if `home-wifi` is ever rendered wrong, the Pi still comes
 back on the LAN rather than stranding itself on the rescue AP.
 The 3B+ has one radio and cannot hold an AP and a station link at the same
 time, so the watchdog cannot listen for the home SSID while the AP is up.
 Instead the AP drops every five minutes to scan -- about seven seconds if the
 home SSID is plainly gone, up to half a minute if it is worth a join attempt --
 and comes back immediately if the home network is still missing. When the home SSID
 does return, the Pi rejoins it and shuts the AP down by itself.
 If you are working over the rescue AP and do not want your session cut:
 ```
 touch /run/wifi-rescue.hold
 ```
 The hold expires after 30 minutes, so a forgotten hold file cannot strand the
 Pi. Deploys take the hold automatically for as long as they run.
 Watch it work with `journalctl -t wifi-rescue -f`.
 ## Adding the printer from a client
 Nothing to install anywhere — the Pi renders.
 - **macOS** — System Settings → Printers → `+`. It appears under its own name
  as an **AirPrint** printer. (`BrowseDNSSDSubTypes _print,_universal` in
  cupsd.conf is what makes macOS offer the driverless add instead of guessing at
  Generic PostScript.)
 - **Windows 10/11** — Add printer; it is discovered as IPP Everywhere / Mopria.
 - **Linux** — discovered by `cups-browsed`, or add
  `ipp://stickah.local:631/printers/labels` by hand.
 ## Access
 LAN only, `192.168.1.0/24`, plus the rescue AP subnet. Enforced twice on
 purpose: at nftables ([templates/nftables.conf.j2](templates/nftables.conf.j2))
 and again in cupsd's own `Location` blocks
 ([templates/cupsd.conf.j2](templates/cupsd.conf.j2)). CUPS is explicitly set
 `--no-remote-any`; the upstream driver's `install.sh` turns that on, which would
 offer this printer to anything that can route to the Pi.
 The Pi patches itself: `unattended-upgrades` is on, with the Raspberry Pi
 archives added to the origins allowlist (Debian's default covers only the Debian
 security origin, which would leave the kernel and firmware — the packages most
 specific to this hardware — unpatched). Kernel updates reboot at 04:00. Nothing
 here holds state across a reboot; a queued job is spooled to disk and resumes.
 ## Secrets
 In `ansible/vars/vault.yml` (`make vault`), no `vault_` prefix, per repo
 convention:
 | Key | What |
 | --- | --- |
 | `stickah_ssid` | Home SSID |
 | `stickah_psk` | Home passphrase, or the 64-hex precomputed PSK |
 | `stickah_ssid_rescue` | Rescue AP SSID |
 | `stickah_psk_rescue` | Rescue AP passphrase (WPA2, 8+ characters) |
@@ -0,0 +1,118 @@
 ---
 # ---------------------------------------------------------------------------
 # Identity
 # ---------------------------------------------------------------------------
 # Reached as stickah.local. There is no DNS record for it: the UDM Pro passes
 # mDNS across the LAN, so avahi on the Pi is the whole of the name service.
 labelprint_hostname: stickah
 # The login the image creates and Ansible connects as. Password auth stays on
 # with a trivial, documented password: this box has to be reachable when the SSH
 # key is not an option -- a reflashed card, a different laptop, someone standing
 # at the workshop bench -- and it is only reachable from the LAN or from its own
 # rescue AP in the first place. The key is what Ansible actually uses.
 labelprint_user: stickah
 labelprint_user_password: stickah
 labelprint_authorized_key_file: ~/.ssh/id_ed25519.pub
 # ---------------------------------------------------------------------------
 # Printer
 # ---------------------------------------------------------------------------
 # Phomemo PM246, 4x6 direct thermal, 203 dpi, speaks TSPL over USB.
 labelprint_queue: labels
 labelprint_queue_info: 4x6 Label Printer (Phomemo PM246)
 labelprint_queue_location: stickah
 # The tspl backend finds the printer's usblp node by USB id. "auto" matches only
 # the ids the driver already knows, and the PM246 is not yet one of them -- so if
 # a deploy leaves the queue unable to find the printer, read the id off the Pi:
 #
 #   for n in /dev/usb/lp*; do udevadm info -q property -n "$n" | grep -E 'ID_(VENDOR|MODEL)_ID|ID_SERIAL_SHORT'; done
 #
 # and pin it here as tspl://<vid>-<pid> (a DASH, not a colon: CUPS parses ":pid"
 # as a port number and rejects the URI), or as tspl:///dev/usb/lp0.
 labelprint_device_uri: "tspl://auto"
 # 203dpi matches the PM246 head. The PPD defaults to 300dpi, which would render
 # every label at ~2/3 scale on this printer.
 labelprint_resolution: 203dpi
 labelprint_media: na_index-4x6_4x6in
 # Cut every other media size out of the PPD, so 4x6 is the only paper a client
 # can pick. Driverless clients build their own PPD from the IPP media-supported
 # list cupsd derives from ours, and there is no lpadmin option that restricts
 # that list -- trimming the PPD is the only lever.
 #
 # The trade is real: the driver's PPD also offers 100x150mm, 4x4, 2.25x1.5, 2x1
 # and a custom range, and this takes all of them away. Set false if you ever
 # want this queue to run stock other than 4x6; a second queue off the untrimmed
 # PPD is the better answer if you want both.
 labelprint_media_only_4x6: true
 # The PPD page-size keyword kept when the above is on. Pairs with
 # labelprint_media, which is the same size under its IPP name.
 labelprint_ppd_pagesize: w288h432
 # 0-15. 8 is the driver's default and a sane starting point for the cheap
 # thermal stock; raise it if barcodes scan poorly, lower it if edges bleed.
 labelprint_darkness: 8
 # in/sec x10. 40 = 4 in/sec.
 labelprint_print_speed: 40
 # ---------------------------------------------------------------------------
 # Driver: RunTheWall/tspl-cups-driver (MIT)
 # ---------------------------------------------------------------------------
 # Built from source at a pinned commit rather than installed from the project's
 # apt repo: this keeps a third-party signing key and package feed off the Pi,
 # and makes the version we run a reviewed, deliberate bump in git history.
 #
 # The vendor Phomemo driver is not an option here -- its rastertolabeltspl
 # filter ships as an x86-64 ELF only, and this host is aarch64.
 labelprint_driver_repo: https://github.com/RunTheWall/tspl-cups-driver.git
 labelprint_driver_version: f433b7774d80a4f6a901b6b998cb710fd79918a4
 labelprint_driver_src: /usr/local/src/tspl-cups-driver
 labelprint_ppd_dir: /usr/share/ppd/tspl
 # The PPD the queue is actually built from.
 labelprint_ppd_active: >-
  {{ labelprint_ppd_dir }}/{{
    'tspl-label-4x6.ppd' if labelprint_media_only_4x6 else 'tspl-label.ppd'
  }}
 # ---------------------------------------------------------------------------
 # Network
 # ---------------------------------------------------------------------------
 # The only subnet allowed to reach CUPS. Everything else is dropped at nftables
 # and refused again by cupsd's own access rules.
 labelprint_lan_cidr: 192.168.1.0/24
 # Rescue access point, brought up when the home SSID is unreachable. The Pi 3B+
 # has a single radio and cannot hold an AP and a station link at once, so this
 # is strictly a fallback -- see templates/wifi-rescue.sh.j2.
 labelprint_ap_addr: 192.168.4.1
 labelprint_ap_cidr: 192.168.4.0/24
 # How often the watchdog checks, and how long the AP stays up before it drops
 # for a few seconds to scan for the home SSID again.
 labelprint_watchdog_interval_secs: 60
 labelprint_ap_rescan_secs: 300
 # How long a hand-placed /run/wifi-rescue.hold pins the radio before the
 # watchdog ignores it. Bounded so a forgotten hold file cannot strand the Pi.
 labelprint_hold_max_age_secs: 1800
 # ---------------------------------------------------------------------------
 # Packages
 # ---------------------------------------------------------------------------
 labelprint_deps:
  [
    avahi-daemon,
    build-essential,
    cups,
    cups-filters,
    dnsmasq-base,
    git,
    libcups2-dev,
    network-manager,
    nftables,
    unattended-upgrades,
  ]
 # Secrets live in ansible/vars/vault.yml (no vault_ prefix, per repo
 # convention): stickah_ssid, stickah_psk,
 # stickah_ssid_rescue, stickah_psk_rescue
@@ -0,0 +1,25 @@
 # Cuts every media size except one out of a CUPS PPD.
 #
 # macOS and Windows add this printer driverless: they never see this PPD, they
 # see the IPP media-supported list cupsd derives from it. Trimming here is
 # therefore the only way to make 4x6 the single choice a client can offer --
 # there is no lpadmin option that restricts the media list.
 #
 # Regenerated from the driver's own PPD on every deploy, so a driver version
 # bump carries its new PPD through this filter rather than being pinned to a
 # fork.
 #
 #   awk -v keep=w288h432 -f trim-ppd-media.awk tspl-label.ppd
 #
 # The four families below are keyed by the PPD page-size keyword in field 2,
 # which reads as "w288h432/4 x 6 in:" -- hence the split on "/".
 /^\*(PageSize|PageRegion|ImageableArea|PaperDimension) / {
    split($2, f, "/")
    if (f[1] != keep) next
 }
 # Custom sizes would put "Manage Custom Sizes" back in the client's paper menu
 # and let a job arrive at any dimension, which is the thing being prevented.
 /^\*(CustomPageSize|ParamCustomPageSize|MaxMediaWidth|MaxMediaHeight)/ { next }
 { print }
@@ -0,0 +1,41 @@
 ---
 - name: restart cups
  become: true
  ansible.builtin.systemd:
    name: cups.service
    state: restarted
 - name: reload udev rules
  become: true
  ansible.builtin.command:
    argv: [udevadm, control, --reload-rules]
  changed_when: true
  notify: trigger udev
 # --action=add, not the default "change": udev only creates SYMLINK+= entries
 # when a device is added, so a change event reloads the rule and leaves
 # /dev/usb/tspl-label missing until the printer is next replugged or rebooted.
 - name: trigger udev
  become: true
  ansible.builtin.command:
    argv: [udevadm, trigger, --subsystem-match=usbmisc, --action=add]
  changed_when: true
 - name: reload systemd
  become: true
  ansible.builtin.systemd:
    daemon_reload: true
 # NetworkManager only reads new keyfiles from disk on request. This does not
 # disturb the live connection.
 - name: reload networkmanager connections
  become: true
  ansible.builtin.command:
    argv: [nmcli, connection, reload]
  changed_when: true
 - name: reload nftables
  become: true
  ansible.builtin.systemd:
    name: nftables.service
    state: reloaded
@@ -0,0 +1,92 @@
 ---
 - name: set the hostname
  become: true
  ansible.builtin.hostname:
    name: "{{ labelprint_hostname }}"
  tags: [labelprint, base]
 # The hostname is also the mDNS name, and avahi publishes whatever is in
 # /etc/hosts for 127.0.1.1. cloud-init writes this line on first boot from the
 # image's own hostname, so it has to be corrected here too or the Pi answers to
 # the wrong .local name.
 - name: point 127.0.1.1 at the hostname
  become: true
  ansible.builtin.lineinfile:
    path: /etc/hosts
    regexp: '^127\.0\.1\.1\s'
    line: "127.0.1.1\t{{ labelprint_hostname }}"
    owner: root
    group: root
    mode: "0644"
  tags: [labelprint, base]
 - name: install the print proxy packages
  become: true
  ansible.builtin.apt:
    name: "{{ labelprint_deps }}"
    state: present
    update_cache: true
    cache_valid_time: 3600
  tags: [labelprint, base]
 - name: publish the host over mDNS
  become: true
  ansible.builtin.systemd:
    name: avahi-daemon.service
    enabled: true
    state: started
  tags: [labelprint, base]
 # ---------------------------------------------------------------------------
 # Unattended security updates
 # ---------------------------------------------------------------------------
 # This box sits on the LAN with an open IPP port and is not something anyone
 # logs into for months at a time, so it patches itself.
 - name: enable unattended upgrades
  become: true
  ansible.builtin.copy:
    dest: /etc/apt/apt.conf.d/20auto-upgrades
    content: |
      APT::Periodic::Update-Package-Lists "1";
      APT::Periodic::Unattended-Upgrade "1";
      APT::Periodic::AutocleanInterval "7";
    owner: root
    group: root
    mode: "0644"
  tags: [labelprint, base, updates]
 # Debian's stock 50unattended-upgrades allowlists the Debian security origin
 # only. Raspberry Pi OS serves its own kernel, firmware and userland from the
 # Raspberry Pi archives, so without these two extra origins the packages most
 # specific to this hardware are exactly the ones that never get patched.
 - name: allow the Raspberry Pi origins and reboot for kernel updates
  become: true
  ansible.builtin.copy:
    dest: /etc/apt/apt.conf.d/52unattended-upgrades-labelprint
    content: |
      Unattended-Upgrade::Origins-Pattern {
          "origin=Raspbian,codename=${distro_codename},label=Raspbian";
          "origin=Raspberry Pi Foundation,codename=${distro_codename},label=Raspberry Pi Foundation";
      };
      Unattended-Upgrade::Remove-Unused-Kernel-Packages "true";
      Unattended-Upgrade::Remove-Unused-Dependencies "true";
      // Nothing here holds state across a reboot -- a queued job is spooled on
      // disk and resumes -- so take the kernel update at 04:00 rather than
      // leaving the Pi running an unpatched kernel until someone notices.
      Unattended-Upgrade::Automatic-Reboot "true";
      Unattended-Upgrade::Automatic-Reboot-Time "04:00";
    owner: root
    group: root
    mode: "0644"
  tags: [labelprint, base, updates]
 - name: enable the unattended-upgrades timers
  become: true
  ansible.builtin.systemd:
    name: "{{ item }}"
    enabled: true
    state: started
  loop:
    - apt-daily.timer
    - apt-daily-upgrade.timer
  tags: [labelprint, base, updates]
@@ -0,0 +1,136 @@
 ---
 - name: configure cupsd
  become: true
  ansible.builtin.template:
    src: cupsd.conf.j2
    dest: /etc/cups/cupsd.conf
    owner: root
    group: lp
    mode: "0640"
    validate: /usr/sbin/cupsd -t -c %s
  notify: restart cups
  tags: [labelprint, cups]
 - name: enable cups
  become: true
  ansible.builtin.systemd:
    name: cups.service
    enabled: true
    state: started
  tags: [labelprint, cups]
 # cupsd.conf has to be in place and cupsd running before lpadmin can talk to it.
 - name: apply pending cups changes before touching the queue
  ansible.builtin.meta: flush_handlers
  tags: [labelprint, cups]
 # ---------------------------------------------------------------------------
 # The queue
 # ---------------------------------------------------------------------------
 # lpadmin is not idempotent and has no "show me everything you would set" mode,
 # so the desired definition is fingerprinted and the fingerprint compared with
 # what was last applied. The marker is written only after lpadmin succeeds.
 # Checksummed here rather than taken from the install task's return value, so
 # that the fingerprint is the same whether or not this run included the driver
 # tasks -- `make deploy-labelprint TAGS=cups` must not look like a change.
 - name: checksum the installed PPD
  become: true
  ansible.builtin.stat:
    path: "{{ labelprint_ppd_active }}"
    checksum_algorithm: sha1
  register: labelprint_ppd_stat
  tags: [labelprint, cups]
 - name: build the desired queue fingerprint
  ansible.builtin.set_fact:
    labelprint_queue_want: >-
      {{
        [
          labelprint_device_uri,
          labelprint_queue_info,
          labelprint_queue_location,
          labelprint_resolution,
          labelprint_media,
          labelprint_darkness | string,
          labelprint_print_speed | string,
          labelprint_ppd_stat.stat.checksum | default('none'),
        ] | join('|')
      }}
  tags: [labelprint, cups]
 - name: read the queue fingerprint that was last applied
  become: true
  ansible.builtin.slurp:
    src: "/etc/cups/.{{ labelprint_queue }}.fingerprint"
  register: labelprint_queue_have
  failed_when: false
  tags: [labelprint, cups]
 - name: create or update the label queue
  become: true
  ansible.builtin.command:
    argv:
      - lpadmin
      - -p
      - "{{ labelprint_queue }}"
      - -E
      - -v
      - "{{ labelprint_device_uri }}"
      - -P
      - "{{ labelprint_ppd_active }}"
      - -D
      - "{{ labelprint_queue_info }}"
      - -L
      - "{{ labelprint_queue_location }}"
      - -o
      - printer-is-shared=true
      - -o
      - "Resolution={{ labelprint_resolution }}"
      - -o
      - "media={{ labelprint_media }}"
      - -o
      - "Darkness={{ labelprint_darkness }}"
      - -o
      - "PrintSpeed={{ labelprint_print_speed }}"
  when: >-
    (labelprint_queue_have.content | default('') | b64decode | trim)
    != labelprint_queue_want | trim
  register: labelprint_lpadmin
  changed_when: true
  tags: [labelprint, cups]
 - name: record the applied queue fingerprint
  become: true
  ansible.builtin.copy:
    dest: "/etc/cups/.{{ labelprint_queue }}.fingerprint"
    content: "{{ labelprint_queue_want | trim }}"
    owner: root
    group: root
    mode: "0600"
  when: labelprint_lpadmin is changed
  tags: [labelprint, cups]
 - name: accept and enable the label queue
  become: true
  ansible.builtin.command:
    argv: ["{{ item }}", "{{ labelprint_queue }}"]
  loop:
    - cupsaccept
    - cupsenable
  changed_when: false
  tags: [labelprint, cups]
 # There is deliberately no `cupsctl` here. It is the obvious way to say
 # "share on the LAN only", but cupsctl edits cupsd.conf through cupsd itself,
 # which rewrites the file from its parsed form and drops every comment. That
 # makes the template above differ on the next run, which re-templates and
 # restarts cups, which lets cupsctl rewrite it again -- a deploy that reports
 # changes forever and never converges.
 #
 # Nothing is lost. `cupsctl --share-printers` amounts to `Browsing On` plus a
 # per-queue shared flag, and both are already set -- the first in the template,
 # the second by lpadmin's printer-is-shared=true above. `--no-remote-any` is the
 # absence of `Allow from all` in <Location />, which is how the template is
 # written. The driver's own install.sh runs `cupsctl --remote-any`, which would
 # offer this printer to anything that can route to the Pi; that is exactly what
 # we are not doing.
@@ -0,0 +1,147 @@
 ---
 # Builds RunTheWall/tspl-cups-driver (MIT) from a pinned commit. The build is
 # three files -- a CUPS raster filter, a backend and a PPD -- so it is cheap to
 # do on the Pi itself and avoids trusting a prebuilt binary.
 - name: fetch the tspl driver source
  become: true
  ansible.builtin.git:
    repo: "{{ labelprint_driver_repo }}"
    dest: "{{ labelprint_driver_src }}"
    version: "{{ labelprint_driver_version }}"
    force: true
  register: labelprint_driver_checkout
  tags: [labelprint, driver]
 - name: check whether the filter is already built
  become: true
  ansible.builtin.stat:
    path: /usr/lib/cups/filter/rastertotspl
  register: labelprint_filter
  tags: [labelprint, driver]
 # `make` alone is not idempotent enough to report honestly -- it prints a
 # recipe line on a rebuild and nothing on a no-op -- so the decision to build is
 # made from the checkout state instead.
 - name: build the tspl raster filter
  become: true
  community.general.make:
    chdir: "{{ labelprint_driver_src }}"
  when: labelprint_driver_checkout.changed or not labelprint_filter.stat.exists
  tags: [labelprint, driver]
 - name: install the tspl raster filter
  become: true
  ansible.builtin.copy:
    src: "{{ labelprint_driver_src }}/src/rastertotspl"
    dest: /usr/lib/cups/filter/rastertotspl
    remote_src: true
    owner: root
    group: root
    mode: "0755"
  notify: restart cups
  tags: [labelprint, driver]
 # 0700 and root-owned on purpose: cupsd refuses to run a backend that is group-
 # or world-writable, and runs it as an unprivileged user if it is not 0700.
 # Writing to the printer's usblp node needs the privileged path.
 - name: install the tspl backend
  become: true
  ansible.builtin.copy:
    src: "{{ labelprint_driver_src }}/backend/tspl"
    dest: /usr/lib/cups/backend/tspl
    remote_src: true
    owner: root
    group: root
    mode: "0700"
  notify: restart cups
  tags: [labelprint, driver]
 - name: create the PPD directory
  become: true
  ansible.builtin.file:
    path: "{{ labelprint_ppd_dir }}"
    state: directory
    owner: root
    group: root
    mode: "0755"
  tags: [labelprint, driver]
 - name: install the tspl PPD
  become: true
  ansible.builtin.copy:
    src: "{{ labelprint_driver_src }}/ppd/tspl-label.ppd"
    dest: "{{ labelprint_ppd_dir }}/tspl-label.ppd"
    remote_src: true
    owner: root
    group: root
    mode: "0644"
  tags: [labelprint, driver]
 # ---------------------------------------------------------------------------
 # The 4x6-only PPD
 # ---------------------------------------------------------------------------
 # Regenerated from the driver's PPD every run rather than kept as a fork, so a
 # driver bump brings its new PPD through the same filter.
 - name: create the helper directory
  become: true
  ansible.builtin.file:
    path: /usr/local/share/labelprint
    state: directory
    owner: root
    group: root
    mode: "0755"
  when: labelprint_media_only_4x6
  tags: [labelprint, driver]
 - name: install the PPD media trim filter
  become: true
  ansible.builtin.copy:
    src: trim-ppd-media.awk
    dest: /usr/local/share/labelprint/trim-ppd-media.awk
    owner: root
    group: root
    mode: "0644"
  when: labelprint_media_only_4x6
  tags: [labelprint, driver]
 - name: render the 4x6-only PPD
  become: true
  ansible.builtin.command:
    argv:
      - awk
      - -v
      - "keep={{ labelprint_ppd_pagesize }}"
      - -f
      - /usr/local/share/labelprint/trim-ppd-media.awk
      - "{{ labelprint_ppd_dir }}/tspl-label.ppd"
  register: labelprint_ppd_trim
  changed_when: false
  when: labelprint_media_only_4x6
  tags: [labelprint, driver]
 - name: install the 4x6-only PPD
  become: true
  ansible.builtin.copy:
    content: "{{ labelprint_ppd_trim.stdout }}\n"
    dest: "{{ labelprint_ppd_dir }}/tspl-label-4x6.ppd"
    owner: root
    group: root
    mode: "0644"
    validate: cupstestppd -q %s
  when: labelprint_media_only_4x6
  tags: [labelprint, driver]
 # Gives the printer a stable /dev/usb/tspl-label symlink across USB
 # re-enumeration. Harmless if the PM246's id is not in the shipped rules -- the
 # backend still finds it by walking /dev/usb/lp*.
 - name: install the tspl udev rules
  become: true
  ansible.builtin.copy:
    src: "{{ labelprint_driver_src }}/udev/99-tspl-label.rules"
    dest: /etc/udev/rules.d/99-tspl-label.rules
    remote_src: true
    owner: root
    group: root
    mode: "0644"
  notify: reload udev rules
  tags: [labelprint, driver]
@@ -0,0 +1,20 @@
 ---
 - name: install the nftables ruleset
  become: true
  ansible.builtin.template:
    src: nftables.conf.j2
    dest: /etc/nftables.conf
    owner: root
    group: root
    mode: "0755"
    validate: /usr/sbin/nft -c -f %s
  notify: reload nftables
  tags: [labelprint, firewall]
 - name: enable nftables
  become: true
  ansible.builtin.systemd:
    name: nftables.service
    enabled: true
    state: started
  tags: [labelprint, firewall]
@@ -0,0 +1,6 @@
 ---
 - import_tasks: base.yml
 - import_tasks: driver.yml
 - import_tasks: cups.yml
 - import_tasks: wifi.yml
 - import_tasks: firewall.yml
@@ -0,0 +1,133 @@
 ---
 # WPA2-PSK takes an 8-63 character passphrase, or exactly 64 hex characters as a
 # precomputed key. NetworkManager stores a shorter one without complaint --
 # psk-flags stays 0 and the value sits in the keyfile -- and then refuses to
 # activate with "Secrets were required, but not provided", which reads like a
 # missing password rather than an invalid one.
 #
 # For the rescue AP that failure is invisible until the day the home network is
 # down and this is the only way in, so it is checked here instead. Only lengths
 # are reported, never the values.
 - name: check the Wi-Fi secrets are usable as WPA2-PSK
  ansible.builtin.assert:
    that:
      - (vars[item] | length >= 8 and vars[item] | length <= 63)
        or (vars[item] is match('^[0-9a-fA-F]{64}$'))
    fail_msg: >-
      {{ item }} is {{ vars[item] | length }} characters, which WPA2 will not
      accept. Use an 8-63 character passphrase, or a 64-character hex
      precomputed key. Fix it with `make vault`.
    quiet: true
  # The loop carries the variable NAME, never its value: a failed assert prints
  # the item it was iterating over, so looping over the secrets themselves would
  # dump both passwords to the terminal on any failure.
  loop:
    - stickah_psk
    - stickah_psk_rescue
  tags: [labelprint, wifi]
 # The watchdog can pull the radio out from under this very play if it decides
 # the Pi is offline while we are mid-deploy over the rescue AP. The hold expires
 # on its own after {{ labelprint_hold_max_age_secs }}s, so an aborted run cannot
 # leave the watchdog disabled.
 - name: hold the radio for the duration of this deploy
  become: true
  ansible.builtin.file:
    path: /run/wifi-rescue.hold
    state: touch
    owner: root
    group: root
    mode: "0644"
  changed_when: false
  tags: [labelprint, wifi]
 - name: install the home Wi-Fi profile
  become: true
  ansible.builtin.template:
    src: home-wifi.nmconnection.j2
    dest: /etc/NetworkManager/system-connections/home-wifi.nmconnection
    owner: root
    group: root
    mode: "0600"
  notify: reload networkmanager connections
  tags: [labelprint, wifi]
 - name: install the rescue access point profile
  become: true
  ansible.builtin.template:
    src: rescue-ap.nmconnection.j2
    dest: /etc/NetworkManager/system-connections/rescue-ap.nmconnection
    owner: root
    group: root
    mode: "0600"
  notify: reload networkmanager connections
  tags: [labelprint, wifi]
 # ---------------------------------------------------------------------------
 # Coexisting with netplan
 # ---------------------------------------------------------------------------
 # The hand-built image configures Wi-Fi through cloud-init's network-config, and
 # on Raspberry Pi OS trixie netplan's NetworkManager integration turns that into
 # a persistent profile of its own at /etc/netplan/90-NM-<uuid>.yaml -- not the
 # /etc/netplan/50-cloud-init.yaml you would expect, and not something a
 # cloud-init clean removes.
 #
 # That profile is deliberately left in place. It carries the same SSID as
 # home-wifi, and autoconnect-priority decides between them: 100 here against
 # netplan's 0, so NetworkManager picks ours every time. What netplan's copy buys
 # is a fallback that predates anything in this role -- if home-wifi is ever
 # rendered wrong, the Pi still comes back on the LAN instead of stranding itself
 # on the rescue AP. Its PSK goes stale when the home password changes; that
 # costs nothing, because a stale profile simply fails and ours is tried first.
 #
 # What is worth stopping is cloud-init rewriting the network on a future
 # re-instance, which would put a third opinion in play.
 - name: stop cloud-init from rewriting the network config
  become: true
  ansible.builtin.copy:
    dest: /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg
    content: |
      network: {config: disabled}
    owner: root
    group: root
    mode: "0644"
  tags: [labelprint, wifi]
 # ---------------------------------------------------------------------------
 # The watchdog
 # ---------------------------------------------------------------------------
 - name: install the Wi-Fi rescue watchdog
  become: true
  ansible.builtin.template:
    src: wifi-rescue.sh.j2
    dest: /usr/local/sbin/wifi-rescue
    owner: root
    group: root
    mode: "0755"
  tags: [labelprint, wifi]
 - name: install the Wi-Fi rescue units
  become: true
  ansible.builtin.template:
    src: "{{ item }}.j2"
    dest: "/etc/systemd/system/{{ item }}"
    owner: root
    group: root
    mode: "0644"
  loop:
    - wifi-rescue.service
    - wifi-rescue.timer
  notify: reload systemd
  tags: [labelprint, wifi]
 - name: apply pending unit changes
  ansible.builtin.meta: flush_handlers
  tags: [labelprint, wifi]
 - name: enable the Wi-Fi rescue watchdog
  become: true
  ansible.builtin.systemd:
    name: wifi-rescue.timer
    enabled: true
    state: started
  tags: [labelprint, wifi]
@@ -0,0 +1,11 @@
 # {{ ansible_managed }} -- rendered by `make bootfs`
 #
 # cloud-init applies user-data once per INSTANCE, not once per boot: rewrite
 # user-data on a card that has already booted and nothing happens, because
 # cloud-init recognises the instance id and skips straight to per-boot modules.
 #
 # Deriving the id from a hash of user-data itself fixes that. Re-running
 # `make bootfs` with no changes leaves the id alone, so a card keeps its
 # identity; change anything in user-data and the id changes with it, and the
 # Pi re-applies the new config on its next boot without a reflash.
 instance-id: {{ labelprint_hostname }}-{{ labelprint_user_data_id }}
@@ -0,0 +1,18 @@
 # {{ ansible_managed }} -- rendered by `make bootfs`
 #
 # Ethernet only, on purpose. Wi-Fi is NOT configured here: cloud-init renders
 # this through netplan into a persistent profile of netplan's own, which is not
 # a file this repo manages or can readily update. The Wi-Fi profiles are written
 # straight into /etc/NetworkManager/system-connections by user-data instead, so
 # the image and Ansible manage the same files.
 #
 # A card that has already booted with Wi-Fi in network-config keeps netplan's
 # profile. That is fine, and useful -- see the "Coexisting with netplan" note in
 # roles/labelprint/tasks/wifi.yml.
 network:
  version: 2
  ethernets:
    eth0:
      dhcp4: true
      dhcp6: true
      optional: true
@@ -0,0 +1,125 @@
 #cloud-config
 # {{ ansible_managed }} -- rendered by `make bootfs BOOTFS=...`
 #
 # First boot of the label print proxy. The job of this file is to make the Pi
 # REACHABLE and nothing more: a login that works, a network that works, and a
 # rescue access point for when it does not. The printer driver and the CUPS
 # queue are Ansible's job -- see roles/labelprint/.
 #
 # The Wi-Fi profiles and the rescue watchdog below are rendered from the very
 # same templates the role uses, so the first `make deploy-labelprint` reports no
 # change on any of them. That is the point: the Pi can already rescue itself
 # before Ansible has ever run.
 #
 # Applies on FIRST BOOT ONLY. Rewriting this file on a card that has already
 # booted does nothing -- reflash the image.
 hostname: {{ labelprint_hostname }}
 manage_etc_hosts: true
 manage_resolv_conf: false
 timezone: America/New_York
 keyboard:
  model: pc105
  layout: "us"
 apt:
  preserve_sources_list: true
 users:
  - name: {{ labelprint_user }}
    shell: /bin/bash
    lock_passwd: false
    # Deliberately trivial, and deliberately not hashed: this password is
    # documented in roles/labelprint/README.md, so a hash of it would protect
    # nothing while pretending otherwise. It exists so that a Pi which will not
    # take the SSH key -- wrong key, reflashed card, someone else's laptop -- is
    # still reachable from the LAN or the rescue AP, which is the only place it
    # can be reached from at all (see templates/nftables.conf.j2).
    plain_text_passwd: {{ labelprint_user_password }}
    sudo: "ALL=(ALL) NOPASSWD:ALL"
    groups: [sudo, adm, lpadmin, plugdev, dialout, netdev, users]
    ssh_authorized_keys:
      - {{ lookup('file', labelprint_authorized_key_file) }}
 # The key is what Ansible actually uses; the password is the fallback.
 ssh_pwauth: true
 disable_root: true
 chpasswd:
  expire: false
 # Pre-installing what the role needs makes the first deploy quick, and means a
 # Pi that comes up on the rescue AP with no internet still has cups and
 # NetworkManager. Ansible installs the same list, so nothing here is load-bearing.
 package_update: true
 packages:
 {% for pkg in labelprint_deps %}
  - {{ pkg }}
 {% endfor %}
 write_files:
  # Stop cloud-init rewriting the network on a future re-instance.
  - path: /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg
    owner: root:root
    permissions: '0644'
    content: |
      network: {config: disabled}
  # Belt and braces. netplan can hand NetworkManager an "only manage what I
  # listed" policy, and what this image lists is eth0; a stock Raspberry Pi OS
  # leaves that policy empty, but an unmanaged wlan0 would take the rescue AP
  # down with it, so it is not worth depending on.
  - path: /etc/NetworkManager/conf.d/10-labelprint.conf
    owner: root:root
    permissions: '0644'
    content: |
      [keyfile]
      unmanaged-devices=none
      [device]
      # A randomised MAC would give the Pi a different DHCP lease on every
      # association, which makes it hard to find on the UDM Pro's client list.
      wifi.scan-rand-mac-address=no
  - path: /etc/NetworkManager/system-connections/home-wifi.nmconnection
    owner: root:root
    permissions: '0600'
    content: |
      {{ lookup('template', 'roles/labelprint/templates/home-wifi.nmconnection.j2') | indent(6) }}
  - path: /etc/NetworkManager/system-connections/rescue-ap.nmconnection
    owner: root:root
    permissions: '0600'
    content: |
      {{ lookup('template', 'roles/labelprint/templates/rescue-ap.nmconnection.j2') | indent(6) }}
  - path: /usr/local/sbin/wifi-rescue
    owner: root:root
    permissions: '0755'
    content: |
      {{ lookup('template', 'roles/labelprint/templates/wifi-rescue.sh.j2') | indent(6) }}
  - path: /etc/systemd/system/wifi-rescue.service
    owner: root:root
    permissions: '0644'
    content: |
      {{ lookup('template', 'roles/labelprint/templates/wifi-rescue.service.j2') | indent(6) }}
  - path: /etc/systemd/system/wifi-rescue.timer
    owner: root:root
    permissions: '0644'
    content: |
      {{ lookup('template', 'roles/labelprint/templates/wifi-rescue.timer.j2') | indent(6) }}
 runcmd:
  # RPi OS soft-blocks the radio until a regulatory domain is known. cmdline.txt
  # carries cfg80211.ieee80211_regdom=US, but unblock anyway -- a blocked radio
  # is the one failure that takes the rescue AP down with it.
  - [rfkill, unblock, wifi]
  - [systemctl, enable, --now, ssh]
  - [systemctl, enable, --now, avahi-daemon]
  # Let NetworkManager pick up the keyfiles written above. The profile netplan
  # renders from network-config is left alone on purpose -- see the "Coexisting
  # with netplan" note in roles/labelprint/tasks/wifi.yml.
  - [nmcli, connection, reload]
  - [systemctl, daemon-reload]
  - [systemctl, enable, --now, wifi-rescue.timer]
@@ -0,0 +1,97 @@
 # {{ ansible_managed }}
 #
 # CUPS on the label print proxy. The Pi does all the rendering, so macOS,
 # Windows and Linux clients add the queue driverless over IPP Everywhere /
 # AirPrint and never install a Phomemo driver.
 #
 # Reachable from the LAN and from the rescue access point only. Everything else
 # is refused here and dropped again at nftables.
 LogLevel warn
 PageLogFormat
 MaxLogSize 1m
 # A label job is worth retrying: the printer is often powered off or out of
 # stock when the job is submitted, and the default is to bin the job outright.
 ErrorPolicy retry-job
 # Only trusted, local networks reach this port -- see the Location blocks below
 # and roles/labelprint/templates/nftables.conf.j2. Listening on all interfaces
 # rather than a fixed address so the queue is still reachable at
 # {{ labelprint_ap_addr }} when the Pi has fallen back to its rescue AP.
 Listen 631
 Listen /run/cups/cups.sock
 # Advertise over Bonjour/mDNS so clients discover the queue by themselves.
 Browsing On
 BrowseLocalProtocols dnssd
 # Dropping the _cups subtype is what makes macOS and iOS offer a driverless
 # "AirPrint" add instead of guessing at a Generic PostScript driver.
 BrowseDNSSDSubTypes _print,_universal
 DefaultAuthType Basic
 WebInterface Yes
 <Location />
  Order allow,deny
  Allow from {{ labelprint_lan_cidr }}
  Allow from {{ labelprint_ap_cidr }}
  Allow from localhost
 </Location>
 <Location /admin>
  AuthType Default
  Require user @SYSTEM
  Order allow,deny
  Allow from {{ labelprint_lan_cidr }}
  Allow from {{ labelprint_ap_cidr }}
 </Location>
 <Location /admin/conf>
  AuthType Default
  Require user @SYSTEM
  Order allow,deny
  Allow from {{ labelprint_lan_cidr }}
  Allow from {{ labelprint_ap_cidr }}
 </Location>
 <Location /admin/log>
  AuthType Default
  Require user @SYSTEM
  Order allow,deny
  Allow from {{ labelprint_lan_cidr }}
  Allow from {{ labelprint_ap_cidr }}
 </Location>
 <Policy default>
  JobPrivateAccess default
  JobPrivateValues default
  SubscriptionPrivateAccess default
  SubscriptionPrivateValues default
  # Anyone on the LAN may print and manage their own jobs -- this is a label
  # printer in a workshop, not a shared office device with quotas.
  <Limit Create-Job Print-Job Print-URI Validate-Job>
    Order deny,allow
  </Limit>
  <Limit Send-Document Send-URI Hold-Job Release-Job Restart-Job Purge-Jobs Set-Job-Attributes Create-Job-Subscription Renew-Subscription Cancel-Subscription Get-Notifications Reprocess-Job Cancel-Current-Job Suspend-Current-Job Resume-Job Cancel-Jobs CUPS-Authenticate-Job Close-Job CUPS-Move-Job Cancel-My-Jobs CUPS-Get-Document>
    Order deny,allow
  </Limit>
  # Changing the printer itself needs a local admin.
  <Limit Pause-Printer Resume-Printer Enable-Printer Disable-Printer Pause-Printer-After-Current-Job Hold-New-Jobs Release-Held-New-Jobs Deactivate-Printer Activate-Printer Restart-Printer Shutdown-Printer Startup-Printer Promote-Job Schedule-Job-After Cancel-Job CUPS-Accept-Jobs CUPS-Reject-Jobs>
    AuthType Default
    Require user @SYSTEM
    Order deny,allow
  </Limit>
  <Limit CUPS-Add-Modify-Printer CUPS-Delete-Printer CUPS-Add-Modify-Class CUPS-Delete-Class CUPS-Set-Default>
    AuthType Default
    Require user @SYSTEM
    Order deny,allow
  </Limit>
  <Limit All>
    Order deny,allow
  </Limit>
 </Policy>
@@ -0,0 +1,32 @@
 # {{ ansible_managed }}
 #
 # The normal, everyday Wi-Fi link. autoconnect-priority outranks anything
 # cloud-init/netplan rendered for the same SSID, so this is the profile
 # NetworkManager picks. autoconnect-retries=0 means retry forever rather than
 # giving up after four attempts and leaving the Pi off the network until
 # someone power-cycles it -- the rescue AP is the fallback, not the
 # destination.
 [connection]
 id=home-wifi
 uuid={{ (stickah_ssid ~ '-home-wifi') | to_uuid }}
 type=wifi
 interface-name=wlan0
 autoconnect=true
 autoconnect-priority=100
 autoconnect-retries=0
 [wifi]
 mode=infrastructure
 ssid={{ stickah_ssid }}
 [wifi-security]
 key-mgmt=wpa-psk
 # Accepts either a passphrase or the 64-hex precomputed PSK.
 psk={{ stickah_psk }}
 [ipv4]
 method=auto
 [ipv6]
 method=auto
 addr-gen-mode=default
@@ -0,0 +1,63 @@
 #!/usr/sbin/nft -f
 # {{ ansible_managed }}
 #
 # The print proxy answers to the LAN and to its own rescue access point, and to
 # nothing else. This is the outer half of the same rule that cupsd enforces in
 # its Location blocks -- both are here on purpose, so a mistake in one is not
 # the only thing standing between the printer and the rest of the world.
 # Declare-then-delete rather than `flush ruleset`: NetworkManager's shared mode
 # keeps its own table for the rescue AP's dnsmasq, and a global flush would take
 # that with it every time this file is reloaded.
 table inet labelprint
 delete table inet labelprint
 table inet labelprint {
    set trusted {
        type ipv4_addr
        flags interval
        elements = { {{ labelprint_lan_cidr }}, {{ labelprint_ap_cidr }} }
    }
    chain input {
        type filter hook input priority filter; policy drop;
        ct state established,related accept
        ct state invalid drop
        iif lo accept
        icmp type { echo-request, destination-unreachable, time-exceeded, parameter-problem } accept
        icmpv6 type { echo-request, destination-unreachable, packet-too-big, time-exceeded, parameter-problem, nd-neighbor-solicit, nd-neighbor-advert, nd-router-advert } accept
        # DHCP replies to our own client. Broadcast, so conntrack does not see
        # them as related to the request we sent.
        udp dport 68 accept
        # ssh and IPP, from the LAN or from a machine on the rescue AP.
        ip saddr @trusted tcp dport { 22, 631 } accept
        ip saddr @trusted udp dport 631 accept
        # mDNS: how every client finds this printer, since it has no DNS record.
        ip saddr @trusted udp dport 5353 accept
        # DHCP for whoever joins the rescue AP. Deliberately not restricted by
        # source address: a client asking for its first lease has no address
        # yet and sends DHCPDISCOVER from 0.0.0.0, so a source-matched rule
        # would mean the rescue network never hands out a lease at all. Only a
        # machine already associated to our own AP can reach this port.
        iifname "wlan0" udp dport 67 accept
        # DNS, once they have an address.
        iifname "wlan0" ip saddr {{ labelprint_ap_cidr }} udp dport 53 accept
        iifname "wlan0" ip saddr {{ labelprint_ap_cidr }} tcp dport 53 accept
    }
    # The rescue AP is a way in to this Pi, not a route to anywhere else.
    chain forward {
        type filter hook forward priority filter; policy drop;
    }
    chain output {
        type filter hook output priority filter; policy accept;
    }
 }
@@ -0,0 +1,38 @@
 # {{ ansible_managed }}
 #
 # Rescue access point. Never autoconnects -- wifi-rescue brings it up only when
 # the home SSID is unreachable, so that a changed password or a dead router
 # leaves a way back in to reconfigure the Pi.
 #
 # Join this SSID and the Pi is at {{ labelprint_ap_addr }}: ssh pi@{{ labelprint_ap_addr }},
 # or print to it directly at ipp://{{ labelprint_ap_addr }}:631/printers/{{ labelprint_queue }}.
 [connection]
 id=rescue-ap
 uuid={{ (stickah_ssid_rescue ~ '-rescue-ap') | to_uuid }}
 type=wifi
 interface-name=wlan0
 autoconnect=false
 [wifi]
 mode=ap
 ssid={{ stickah_ssid_rescue }}
 # The 3B+ radio does 5 GHz, but 2.4 GHz AP mode is what brcmfmac is reliable
 # at, and a rescue network only has to carry an SSH session.
 band=bg
 channel=6
 [wifi-security]
 key-mgmt=wpa-psk
 proto=rsn
 pairwise=ccmp
 group=ccmp
 psk={{ stickah_psk_rescue }}
 # "shared" makes NetworkManager run a dnsmasq for DHCP and DNS on this
 # interface, so a laptop that joins gets an address without any further setup.
 [ipv4]
 method=shared
 address1={{ labelprint_ap_addr }}/24
 [ipv6]
 method=ignore
@@ -0,0 +1,9 @@
 # {{ ansible_managed }}
 [Unit]
 Description=Wi-Fi rescue access point watchdog
 After=NetworkManager.service
 Requires=NetworkManager.service
 [Service]
 Type=oneshot
 ExecStart=/usr/local/sbin/wifi-rescue
@@ -0,0 +1,132 @@
 #!/bin/sh
 # {{ ansible_managed }}
 #
 # Keeps the label print proxy reachable.
 #
 # Normally the Pi is a station on the home SSID. If that network is gone -- the
 # password changed, the AP died, the Pi was carried somewhere else -- it brings
 # up its own rescue access point so there is still a way in to reconfigure it.
 # It keeps checking, and hands the radio back the moment the home SSID returns.
 #
 # The 3B+ has one radio and brcmfmac will not hold an AP and a station link at
 # the same time, so this cannot listen for the home SSID while the AP is up.
 # Instead the AP drops for a few seconds every {{ labelprint_ap_rescan_secs }}s
 # to scan, and comes straight back if the home network is still missing.
 #
 # If you are working over the rescue AP and do not want the radio pulled out
 # from under your SSH session:
 #
 #     touch /run/wifi-rescue.hold
 #
 # The hold expires by itself after {{ (labelprint_hold_max_age_secs / 60) | int }} minutes, so a forgotten hold file
 # cannot strand the Pi permanently.
 set -eu
 HOME_CON=home-wifi
 AP_CON=rescue-ap
 SSID='{{ stickah_ssid }}'
 AP_SSID='{{ stickah_ssid_rescue }}'
 IFACE=wlan0
 HOLD=/run/wifi-rescue.hold
 STAMP=/run/wifi-rescue.ap-since
 RESCAN_SECS={{ labelprint_ap_rescan_secs }}
 HOLD_MAX_AGE={{ labelprint_hold_max_age_secs }}
 log() { logger -t wifi-rescue -- "$@"; }
 con_active() { nmcli -t -f NAME connection show --active | grep -qxF "$1"; }
 # A default IPv4 route is the honest test for "on a real network". The rescue
 # AP uses NetworkManager's shared mode, which hands out addresses but installs
 # no default route, so the AP can never make this look true.
 online() { [ -n "$(ip -4 route show default 2>/dev/null)" ]; }
 held() {
    [ -e "$HOLD" ] || return 1
    age=$(( $(date +%s) - $(stat -c %Y "$HOLD" 2>/dev/null || echo 0) ))
    if [ "$age" -lt "$HOLD_MAX_AGE" ]; then
        return 0
    fi
    log "hold file is ${age}s old; expiring it"
    rm -f "$HOLD"
    return 1
 }
 start_ap() {
    con_active "$AP_CON" && return 0
    log "starting rescue AP '$AP_SSID' on {{ labelprint_ap_addr }}"
    if nmcli --wait 20 connection up "$AP_CON" >/dev/null 2>&1; then
        date +%s > "$STAMP"
    else
        log "ERROR: rescue AP failed to start"
    fi
 }
 join_home() {
    # Bounded: the default 90s wait outlives the watchdog interval, and an
    # SSID that is not there is not going to appear in the next minute.
    #
    # --wait is a GLOBAL nmcli option and has to precede the subcommand. Written
    # as `connection up <id> --wait 20` it is rejected outright with "invalid
    # extra argument" -- and only for a connection that exists, so it looks fine
    # against a typo'd name. That failure mode is silent and total: every join
    # returns failure and the rescue AP never starts.
    nmcli --wait 20 connection up "$HOME_CON" >/dev/null 2>&1 || return 1
    online
 }
 held && exit 0
 if online; then
    if con_active "$AP_CON"; then
        log "back on the network; shutting the rescue AP down"
        nmcli connection down "$AP_CON" >/dev/null 2>&1 || true
        rm -f "$STAMP"
    fi
    exit 0
 fi
 if con_active "$AP_CON"; then
    since=$(cat "$STAMP" 2>/dev/null || echo 0)
    [ $(( $(date +%s) - since )) -lt "$RESCAN_SECS" ] && exit 0
    log "rescue AP up for ${RESCAN_SECS}s; dropping it to scan for '$SSID'"
    nmcli connection down "$AP_CON" >/dev/null 2>&1 || true
    sleep 2
    nmcli device wifi rescan ifname "$IFACE" >/dev/null 2>&1 || true
    sleep 5
    scan=$(nmcli -t -f SSID device wifi list ifname "$IFACE" 2>/dev/null || true)
    if printf '%s\n' "$scan" | grep -qxF "$SSID"; then
        log "'$SSID' is back; rejoining"
        try=yes
    elif [ -z "$(printf '%s' "$scan" | tr -d '[:space:]')" ]; then
        # Nothing at all came back. Either the radio has not settled after
        # dropping the AP, or the home SSID is hidden and will never show up in
        # a scan. Worth 20 seconds to find out.
        log "scan came back empty; trying '$SSID' anyway"
        try=yes
    else
        # Other networks are visible and ours is not, so it really is gone.
        # Straight back to the AP -- no point spending the join timeout.
        try=no
    fi
    if [ "$try" = yes ]; then
        if join_home; then
            log "rejoined '$SSID'"
            rm -f "$STAMP"
            exit 0
        fi
        log "join failed; returning to the rescue AP"
    fi
    start_ap
    exit 0
 fi
 log "offline and no rescue AP; trying '$SSID'"
 if join_home; then
    log "joined '$SSID'"
    exit 0
 fi
 start_ap
@@ -0,0 +1,13 @@
 # {{ ansible_managed }}
 [Unit]
 Description=Run the Wi-Fi rescue watchdog every {{ labelprint_watchdog_interval_secs }}s
 [Timer]
 # Waits for NetworkManager to have had a fair go at the home SSID before the
 # first check, so a slow DHCP lease at boot does not trip the rescue AP.
 OnBootSec=90
 OnUnitActiveSec={{ labelprint_watchdog_interval_secs }}
 AccuracySec=5
 [Install]
 WantedBy=timers.target