ansible/roles/pi_musicmouse/tasks/main.yml

---
- name: Packages
  ansible.builtin.apt:
    name:
      - git
      - libvlc5 # runtime lib python-vlc binds against
      - vlc-plugin-base
      - alsa-utils
      - samba
      - python3
      - python3-venv
      - python3-pip
    cache_valid_time: 7200

- name: Checkout Musicmouse repo
  ansible.builtin.git:
    repo: "{{ pi_musicmouse_repo }}"
    dest: /opt/musicmouse
    version: "{{ musicmouse_version }}"
    accept_hostkey: true
    force: true
  register: pi_musicmouse_checkout

- name: Check the checkout has the layout this role knows
  ansible.builtin.stat:
    path: /opt/musicmouse/python-backend/pyproject.toml
  register: pi_musicmouse_pyproject
  # Meaningless under --check on a host that has never been deployed: the git task
  # above reports "changed" without writing anything, so there is nothing to stat.
  when: not ansible_check_mode

- name: Fail on a pre-rearchitecture checkout
  ansible.builtin.fail:
    msg: >-
      {{ musicmouse_version }} has no python-backend/pyproject.toml, so it predates the
      rearchitecture and this role cannot install it - the venv, the systemd unit and
      the web/ build all live somewhere else on those commits. Point
      musicmouse_version at a branch that has it (deploy/musicdolphin), or set
      mediapi_install_kidsmusic to false for this host and leave whatever is installed
      alone. Stopping here rather than failing three tasks deeper with the real reason
      buried.
  when: not ansible_check_mode and not pi_musicmouse_pyproject.stat.exists

- name: Get the system Python version
  ansible.builtin.command:
    cmd: python3 -c "import sys; print('%d.%d' % sys.version_info[:2])"
  register: pi_musicmouse_system_python
  changed_when: false

- name: Get the version the venv was built with
  ansible.builtin.command:
    cmd: /opt/musicmouse/.venv/bin/python -c "import sys; print('%d.%d' % sys.version_info[:2])"
  register: pi_musicmouse_venv_python
  changed_when: false
  failed_when: false

- name: Discard a venv built by a different Python
  # `creates:` below would otherwise keep an old interpreter forever - which is exactly
  # what a switch away from a separately-installed Python leaves behind. A venv holds
  # absolute paths into the interpreter that made it, so it cannot be migrated; the
  # cheap and correct move is to rebuild it.
  ansible.builtin.file:
    path: /opt/musicmouse/.venv
    state: absent
  when: >-
    pi_musicmouse_venv_python.rc == 0
    and pi_musicmouse_venv_python.stdout | trim != pi_musicmouse_system_python.stdout | trim

- name: Create the virtualenv from the system Python
  ansible.builtin.command:
    cmd: "python3 -m venv /opt/musicmouse/.venv"
    creates: /opt/musicmouse/.venv/bin/python

# Installing the backend is deliberately not a handler hanging off the checkout.
# Tied to the checkout, one failed run strands the device: the notification is dropped
# when the play fails, the next run finds the checkout already current and notifies
# nothing, and the venv stays empty while the service crash-loops on
# ModuleNotFoundError. Instead, decide from what is actually on the device - the commit
# it has checked out, and whether the venv can import the package at all.
#
# pip's own output cannot answer this either: `musicmouse` is a local path dependency,
# so every run rebuilds and reinstalls it. Keying off that restarts the service on
# every run and rescans the whole library for nothing.
- name: Read which commit the venv was built from
  ansible.builtin.command:
    cmd: cat /opt/musicmouse/.venv/.installed-commit
  register: pi_musicmouse_stamp
  changed_when: false
  failed_when: false

- name: Check the venv can actually import the backend
  ansible.builtin.command:
    cmd: /opt/musicmouse/.venv/bin/python -c "import musicmouse"
  register: pi_musicmouse_importable
  changed_when: false
  failed_when: false

- name: Install the backend into the venv
  ansible.builtin.command:
    cmd: "/opt/musicmouse/.venv/bin/pip install /opt/musicmouse/python-backend"
  when: >-
    pi_musicmouse_importable.rc != 0
    or pi_musicmouse_stamp.stdout | trim != pi_musicmouse_commit
  changed_when: true # guarded by `when`, so reaching this means it installed something
  notify: Restart musicmouse

- name: Record which commit the venv was built from
  ansible.builtin.copy:
    content: "{{ pi_musicmouse_commit }}\n"
    dest: /opt/musicmouse/.venv/.installed-commit
    mode: "0644"

- name: Create media directory
  ansible.builtin.file:
    path: /media/musicmouse
    state: directory
    mode: "0755"

- name: Install config file
  ansible.builtin.copy:
    src: "{{ pi_musicmouse_config_file }}"
    dest: /media/musicmouse/config.yml
    mode: "0644"
    # Install-once: the app writes this file itself (parent mode's volume keys, the
    # remote-control mapping). See pi_musicmouse_force_config in defaults.
    force: "{{ pi_musicmouse_force_config }}"
  notify: Restart musicmouse

- name: Install tippen curriculum
  ansible.builtin.copy:
    src: "{{ pi_musicmouse_curriculum_file }}"
    dest: /media/musicmouse/tippen-curriculum.yml
    mode: "0644"
  when: pi_musicmouse_curriculum_file | length > 0
  notify: Restart musicmouse

- name: Install systemd service file (from the checked-out repo, not a copy kept here)
  ansible.builtin.copy:
    src: /opt/musicmouse/python-backend/musicmouse.service
    dest: /etc/systemd/system/musicmouse.service
    mode: "0644"
    remote_src: true
  notify: Restart musicmouse

- name: Add script to autostart and start now
  ansible.builtin.systemd:
    name: musicmouse
    state: started
    enabled: "yes"
    daemon_reload: "yes"

- name: Ensure local frontend build cache directory exists
  ansible.builtin.file:
    path: "{{ pi_musicmouse_build_cache }}/{{ musicmouse_version | regex_replace('/', '_') }}"
    state: directory
    mode: "0755"
  delegate_to: localhost
  become: false
  vars:
    # `become: false` above is not enough on its own. pi_standard_setup's defaults set
    # `ansible_become: true`, role defaults are play-wide host variables, and the
    # `ansible_become` *variable* outranks the `become` *keyword* in Ansible's
    # precedence - so every task here tried to sudo on the control machine. Those
    # defaults are needed to bootstrap a fresh Pi (connect as `pi`, become root, enable
    # root login), so override the variable here rather than removing them.
    ansible_become: false

- name: Checkout Musicmouse repo for frontend build (control machine)
  ansible.builtin.git:
    repo: "{{ pi_musicmouse_repo }}"
    dest: "{{ pi_musicmouse_build_cache }}/{{ musicmouse_version | regex_replace('/', '_') }}"
    version: "{{ musicmouse_version }}"
    accept_hostkey: true
    force: true
  delegate_to: localhost
  become: false
  vars:
    ansible_become: false  # see the first delegated task in tasks/main.yml
  notify: Build frontend

- name: Check whether the device has a built frontend
  ansible.builtin.stat:
    path: /opt/musicmouse/web/dist/index.html
  register: pi_musicmouse_dist

- name: Queue a frontend build when the device has none
  # The build chain hangs off the control machine's checkout changing, which has the
  # same hole the backend install had: a run that fails after that checkout leaves the
  # Pi with no dist, and every later run finds the checkout current and rebuilds
  # nothing. Cheap to check, and it only fires when the device really has no UI.
  ansible.builtin.debug:
    msg: "No frontend at /opt/musicmouse/web/dist - queueing a build"
  when: not pi_musicmouse_dist.stat.exists
  changed_when: true
  notify: Build frontend

- name: Samba setup
  ansible.builtin.copy:
    src: smb.conf
    dest: /etc/samba/
    mode: "0644"

- name: Restart samba
  ansible.builtin.systemd:
    name: smbd
    state: restarted
    enabled: "yes"
    daemon_reload: "yes"
# manual steps:
#    - set samba passwords with smbpasswd
#    - copy music into /media/musicmouse: scripts/sync-library.sh in the app repo, which
#      also carries the cover and analysis cache over (or use the samba share, and let
#      the device spend the DSP time itself)