gitlab_runner: Add service to cleanup docker artifacts produced by the runner

roles/gitlab_runner/files/gitlab-runner-docker-cleanup.service

+[Unit]
+Description=Cleanup containers, images and volumes produced by GitLab Runner
+
+[Service]
+Type=oneshot
+ExecStart=docker system prune --force --filter label=com.gitlab.gitlab-runner.managed=true --volumes
+ExecStart=docker image prune --all --force --filter until=168h

roles/gitlab_runner/files/gitlab-runner-docker-cleanup.timer

+[Unit]
+Description=Run gitlab-runner-docker-cleanup.service daily
+
+[Timer]
+OnCalendar=weekly
+Persistent=true
+RandomizedDelaySec=1d
+
+[Install]
+WantedBy=timers.target

roles/gitlab_runner/handlers/main.yml

@@ -4,5 +4,8 @@
 - name: restart gitlab-runner
   service: name=gitlab-runner state=restarted
 
+- name: restart gitlab-runner-docker-cleanup.timer
+  service: name=gitlab-runner-docker-cleanup.timer state=restarted daemon_reload=yes
+
 - name: restart docker
   service: name=docker state=restarted

roles/gitlab_runner/tasks/main.yml

@@ -64,5 +64,16 @@
     line: listen_address = ":{{ gitlab_runner_exporter_port }}"
   notify: restart gitlab-runner
 
+- name: install gitlab-runner-docker-cleanup.{service,timer}
+  copy: src={{ item }} dest=/etc/systemd/system/{{ item }} owner=root group=root mode=0644
+  loop:
+    - gitlab-runner-docker-cleanup.service
+    - gitlab-runner-docker-cleanup.timer
+  notify:
+    - restart gitlab-runner-docker-cleanup.timer
+
+- name: enable and start gitlab-runner-docker-cleanup.timer
+  systemd: name=gitlab-runner-docker-cleanup.timer state=started enabled=yes daemon_reload=yes
+
 - name: enable and start gitlab runner service
   systemd: name=gitlab-runner state=started enabled=yes daemon_reload=yes