Merge "Add support for yum caching when buildah updates"

README.rst

@@ -54,7 +54,15 @@ Role Variables
    * - `container_build_tool`
      - `docker`
      - See modify image variables
-
+   * - `yum_cache`
+     - `None`
+     - Optional path to the host directory for yum cache during the update.
+       Requires an overlay-enabled FS that also supports SE context relabling.
+       Works only with container_build_tool=buildah.
+   * - `force_purge_yum_cache`
+     - `False`
+     - Optional argument that tells buildah to forcefully re-populate the yum
+       cache with new contents.
 
 .. list-table:: Variables used for yum install
    :widths: auto
@@ -185,7 +193,8 @@ In this playbook the tasks\_from is set as a variable instead of an
           source_image: docker.io/tripleomaster/centos-binary-nova-api:latest
           yum_repos_dir_path: /etc/yum.repos.d
           modified_append_tag: updated
-          container_build_tool: docker # or buildah
+          container_build_tool: buildah # or docker
+          yum_cache: /tmp/containers-updater/yum_cache
 
 Note, if you have a locally installed gating repo, you can add
 ``update_repo: gating-repo``. This may be the case for the consequent in-place

defaults/main.yml

@@ -4,3 +4,4 @@ container_build_tool: 'docker'
 python_dir: []
 refspecs: []
 yum_packages: []
+force_purge_yum_cache: false

tasks/yum_update_buildah.yml

@@ -22,9 +22,21 @@
     state: file
   register: yum_update
 
+- name: Identify the primary pkg mgr (dnf or yum)
+  shell: command -v dnf || command -v yum
+  register: pkg_mgr_output
+
+- name: Set fact for the used pkg mgr binary
+  set_fact:
+    pkg_mgr: "{{ pkg_mgr_output.stdout }}"
+
+- name: Set fact for the used pkg mgr cache path
+  set_fact:
+    cache_path: /var/cache/{{ pkg_mgr.split('/')[-1] }}
+
 - name: Prepare yum_update.sh script
-  copy:
-    src: files/yum_update.sh
+  template:
+    src: yum_update.sh.j2
     dest: "{{ yum_update.path }}"
     mode: 0755
 
@@ -34,12 +46,58 @@
     chdir: "{{ yum_repos_dir_path }}"
   register: file_repos
 
+- name: Define bind-mount modes for yum cache to be populated or used
+  when: yum_cache is defined and yum_cache
+  block:
+    - name: Check for the pkg mgr cache existence
+      stat:
+        path: "{{ yum_cache }}"
+        get_checksum: false
+      register: yum_cache_stat
+
+    - name: Check for the pkg mgr cach contents
+      shell: ls -A {{ yum_cache }}
+      register: yum_cache_contents
+      when: yum_cache_stat.stat.exists|default()
+
+    - name: Purge the pgh mgr cache on host
+      file:
+        path: "{{ yum_cache }}"
+        state: absent
+      when:
+        - force_purge_yum_cache|bool
+        - yum_cache_contents is defined
+        - yum_cache_contents.stdout
+
+    - name: Ensure the pgh mgr cache path exists
+      file:
+        path: "{{ yum_cache }}"
+        state: directory
+        mode: 0755
+        setype: svirt_sandbox_file_t
+      when: not yum_cache_stat.stat.exists|default()
+
+    - name: Use the pre-populated non-empty cache as an overlay fs
+      set_fact:
+        cache_volume: "{{ yum_cache }}:{{ cache_path }}:O"
+      when:
+        - yum_cache_stat.stat.exists|default()
+        - yum_cache_contents.stdout
+
+    - name: Define the cache populating mode otherwise
+      set_fact:
+        cache_volume: "{{ yum_cache }}:{{ cache_path }}:rw,z"
+      when: cache_volume is not defined
+
 - block:
     - name: Run yum_update.sh
       command: >
         buildah run
           --volume {{ yum_update.path }}:/tmp/yum_update.sh
           --volume {{ yum_repos_dir_path }}:/etc/yum.repos.d
+          {% if cache_volume is defined and cache_volume %}
+          --volume {{ cache_volume }}
+          {% endif %}
           {% for repo in file_repos.stdout_lines %}
             {% if repo|exists %}
               --volume {{ repo }}:{{ repo }}
@@ -57,6 +115,9 @@
         buildah --debug run
           --volume {{ yum_update.path }}:/tmp/yum_update.sh
           --volume {{ yum_repos_dir_path }}:/etc/yum.repos.d
+          {% if cache_volume is defined and cache_volume %}
+          --volume {{ cache_volume }}
+          {% endif %}
           {% for repo in file_repos.stdout_lines %}
             {% if repo|exists %}
               --volume {{ repo }}:{{ repo }}

templates/yum_update.sh.j2

@@ -2,7 +2,7 @@
 
 set -eou pipefail
 
-PKG="$(command -v dnf || command -v yum)"
+PKG={{ pkg_mgr }}
 PKG_MGR="$(echo ${PKG:(-3)})"
 
 if [ $PKG_MGR == "dnf" ]; then
@@ -44,4 +44,8 @@ if $(! echo $installed | grep -qw $plugin) && $($PKG list available $plugin >/de
 fi
 
 $PKG -y update $packages_for_update
+{% if yum_cache is defined and yum_cache %}
+sync
+{% else %}
 rm -rf /var/cache/$PKG_MGR
+{% endif %}