用于更改Docker映像并重新创建Docker容器的Ansible工作流？

Question

I've been struggling with figuring out what the proper Ansible workflow is for deploying a Docker image and recreating a Docker container if the image has changed.

Here's the task list of a role I initially thought would work:

- name: Deploy Source
  synchronize:
    archive: yes
    checksum: yes
    compress: yes
    dest: '/tmp/{{ app_name }}'
    src: ./

- name: Build Docker Image
  docker_image:
    name: '{{ docker_image_name }}'
    path: '/tmp/{{ app_name }}'
    rm: yes
    state: present
  register: build_docker_image

- name: Create Docker Container
  docker_container:
    image: '{{ docker_image_name }}'
    keep_volumes: yes
    name: '{{ docker_container_name }}'
    recreate: '{{ true if build_docker_image.changed else omit }}'
    state: started

This does not work because the Ansible docker_image module does not offer a state: latest option. state: present only checks if the image exists and not if it's up to date. This means that even if the Dockerfile has changed, the image will not be rebuilt. docker_image does offer a force: yes option, but this will always recreate the image regardless of whether there was a change to the Dockerfile . When force: yes is used, it makes sense to me that it's better to always recreate containers running the image to prevent them from pointing to dangling Docker images.

What am I missing? Is there a better alternative?

Answer 1

User viggeh provided a workaround on the Ansible GitHub which I've adapted to my needs as follows:

- name: Deploy Source
  synchronize:
    archive: yes
    checksum: yes
    compress: yes
    dest: '/tmp/{{ app_name }}'
    src: ./

- name: Get Existing Image ID
  command: 'docker images --format {% raw %}"{{.ID}}"{% endraw %} --no-trunc {{ docker_image_name }}:{{ docker_image_tag }}'
  register: image_id
  changed_when: image_id.rc != 0

- name: Build Docker Image
  docker_image:
    force: yes
    name: '{{ docker_image_name }}'
    path: '/tmp/{{ app_name }}'
    rm: yes
    state: present
    tag: '{{ docker_image_tag }}'
  register: image_build
  changed_when: image_id.stdout != image_build.image.Id

- name: Create Docker Container
  docker_container:
    image: '{{ docker_image_name }}'
    keep_volumes: yes
    name: '{{ docker_container_name }}'
    recreate: '{{ True if image_build.changed else omit }}'
    state: started