Define task to load docker containers from archive

Author: Kevinjil

provision-contest/ansible/README.md

@@ -44,6 +44,7 @@ There are a few places where additional files should/can be added:
 * Machine/group specific local packages under `roles/base_packages/files/install-*/`.
 * Judgehost chroot local packages under `roles/judgedaemon/files/install-chroot/`.
 * The vendor dependencies under `roles/domjudge_checkout/files/vendor.tgz`.
+* Machine/group specific docker containers under `roles/docker/files/containers-*/`.
 
 ## TODO
 

provision-contest/ansible/roles/docker/files/README.md

@@ -0,0 +1,5 @@
+# Loading containers from archives
+Any container `.tar` files placed in a `containers-<host_type>` directory will be loaded as a container for the said host type.
+The container will be tagged  with the relative path starting from `containers-<host_type>`, without the `.tar` file extension.
+For example, the file `containers-glitchtip/glitchtip/glitchtip:v4.1.3.tar` will be loaded as a container tagged `glitchtip/glitchtip:v4.1.3` for the `glitchtip` host type.
+Note that a nested directory structure is needed to tag containers which have both an organization and a container name.

provision-contest/ansible/roles/docker/tasks/load-container.yml

@@ -0,0 +1,35 @@
+---
+- name: Load the container from archive if needed
+  block:
+    - name: Check for existing container
+      community.docker.docker_image_info:
+        name: "{{ img_name }}"
+      register: result
+
+    - name: Transfer and load the container
+      block:
+        - name: Create temp container directory
+          file:
+            path: /tmp/dj_ansible
+            state: directory
+            owner: root
+            group: root
+            mode: 0700
+
+        - name: Transfer container archive
+          copy:
+            src: "{{ item.src }}"
+            dest: "{{ img_path }}"
+            owner: root
+            group: root
+            mode: 0700
+
+        - name: Import container from archive
+          community.docker.docker_image:
+            name: "{{ img_name }}"
+            load_path: "{{ img_path }}"
+            source: load
+      when: not result.images
+  vars:
+    img_name: "{{ item.path | splitext | first }}"
+    img_path: "/tmp/dj_ansible/{{ item.path | basename }}"

provision-contest/ansible/roles/docker/tasks/main.yml

@@ -22,3 +22,9 @@
       - docker-compose-plugin
       - python3-pip
       - python3-docker
+
+- name: Load container archives
+  include_tasks: load-container.yml
+  with_filetree:
+    - files/containers-{{ host_type }}/
+  when: item.state == 'file' and (item.path | splitext | last) == ".tar"