docker: add housekeeping (#105)

Reviewed-on: #105
Co-authored-by: Michael Grote <michael.grote@posteo.de>
Co-committed-by: Michael Grote <michael.grote@posteo.de>

playbooks/3_service/docker.yml

@@ -19,3 +19,6 @@
     - role: mgrote_docker_compose_inline
       tags: "compose"
       become: true
+    - role: mgrote_docker_housekeeping
+      tags: "housekeeping"
+      become: true

roles/mgrote_docker_housekeeping/defaults/main.yml

@@ -0,0 +1,3 @@
+---
+docker_housekeeping_schedule: "weekly"
+...

roles/mgrote_docker_housekeeping/handlers/main.yml

@@ -0,0 +1,14 @@
+---
+- name: systemctl daemon-reload
+  become: true
+  ansible.builtin.systemd:
+    daemon_reload: true
+  notify: Start timer
+
+- name: Start timer
+  become: true
+  ansible.builtin.systemd:
+    name: docker_housekeeping.timer
+    state: restarted
+    enabled: true
+  notify: systemctl daemon-reload

roles/mgrote_docker_housekeeping/tasks/main.yml

@@ -0,0 +1,36 @@
+---
+- name: Setup docker housekeeping tasks
+  become: true
+  ansible.builtin.template:
+    src: docker_housekeeping.service.j2
+    dest: /etc/systemd/system/docker_housekeeping.service
+    owner: root
+    group: root
+    mode: "0644"
+  notify:
+    - systemctl daemon-reload
+
+- name: Setup timer
+  become: true
+  ansible.builtin.template:
+    src: docker_housekeeping.timer.j2
+    dest: /etc/systemd/system/docker_housekeeping.timer
+    owner: root
+    group: root
+    mode: "0644"
+  notify:
+    - systemctl daemon-reload
+    - Start timer
+
+- name: Enable Units
+  become: true
+  ansible.builtin.systemd:
+    name: "{{ item }}"
+    enabled: true
+    masked: false
+  with_items:
+    - docker_housekeeping.service
+    - docker_housekeeping.timer
+  notify:
+    - Start timer
+...

roles/mgrote_docker_housekeeping/templates/docker_housekeeping.service.j2

@@ -0,0 +1,8 @@
+{{ file_header | default () }}
+[Unit]
+Description=Docker housekeeping tasks
+
+[Service]
+Type=simple
+ExecStart=/usr/bin/docker system prune --force --filter "until=24h"
+# https://docs.docker.com/config/pruning

roles/mgrote_docker_housekeeping/templates/docker_housekeeping.timer.j2

@@ -0,0 +1,11 @@
+{{ file_header | default () }}
+[Unit]
+Description=Timer for docker_housekeeping backups.
+
+[Timer]
+# https://wiki.archlinux.org/title/systemd/Timers
+OnCalendar={{ docker_housekeeping_schedule }}
+RandomizedDelaySec=30 min
+
+[Install]
+WantedBy=timers.target multi-user.target