Using Docker Containers with Molecule for Ansible Testing

dependency:
  name: galaxy
  options:
    requirements-file: requirements.yml
platforms:
  - name: molecule-ubuntu
    image: ubuntu:22.04

collections:
  - community.docker

- name: Create
  hosts: localhost
  gather_facts: false
  vars:
    molecule_inventory:
      all:
        hosts: {}
        molecule: {}
  tasks:
    - name: Create a container
      community.docker.docker_container:
        name: "{{ item.name }}"
        image: "{{ item.image }}"
        state: started
        command: sleep 1d
        log_driver: json-file
      register: result
      loop: "{{ molecule_yml.platforms }}"

    - name: Print some info
      ansible.builtin.debug:
        msg: "{{ result.results }}"

    - name: Fail if container is not running
      when: >
        item.container.State.ExitCode != 0 or
        not item.container.State.Running        
      ansible.builtin.include_tasks:
        file: tasks/create-fail.yml
      loop: "{{ result.results }}"
      loop_control:
        label: "{{ item.container.Name }}"

    - name: Add container to molecule_inventory
      vars:
        inventory_partial_yaml: |
          all:
            children:
              molecule:
                hosts:
                  "{{ item.name }}":
                    ansible_connection: community.docker.docker          
      ansible.builtin.set_fact:
        molecule_inventory: >
          {{ molecule_inventory | combine(inventory_partial_yaml | from_yaml, recursive=true) }}          
      loop: "{{ molecule_yml.platforms }}"
      loop_control:
        label: "{{ item.name }}"

    - name: Dump molecule_inventory
      ansible.builtin.copy:
        content: |
          {{ molecule_inventory | to_yaml }}          
        dest: "{{ molecule_ephemeral_directory }}/inventory/molecule_inventory.yml"
        mode: "0600"

    - name: Force inventory refresh
      ansible.builtin.meta: refresh_inventory

    - name: Fail if molecule group is missing
      ansible.builtin.assert:
        that: "'molecule' in groups"
        fail_msg: |
          molecule group was not found inside inventory groups: {{ groups }}          
      run_once: true # noqa: run-once[task]

	- name: Validate that inventory was refreshed
	  hosts: molecule
	  gather_facts: false
	  tasks:
	    - name: Check uname
	      ansible.builtin.raw: uname -a
	      register: result
	      changed_when: false

	    - name: Display uname info
	      ansible.builtin.debug:
	        msg: "{{ result.stdout }}"

- name: Fail if molecule group is missing
  hosts: localhost
  tasks:
    - name: Print some info
      ansible.builtin.debug:
        msg: "{{ groups }}"

    - name: Assert group existence
      ansible.builtin.assert:
        that: "'molecule' in groups"
        fail_msg: |
          molecule group was not found inside inventory groups: {{ groups }}          

	- name: Converge
	  hosts: molecule
	  gather_facts: false
	  tasks:
	    - name: Check uname
	      ansible.builtin.raw: uname -a
	      register: result
	      changed_when: false

	    - name: Print some info
	      ansible.builtin.assert:
	        that: result.stdout | regex_search("^Linux")

- name: Destroy molecule containers
  hosts: molecule
  gather_facts: false
  tasks:
    - name: Stop and remove container
      delegate_to: localhost
      community.docker.docker_container:
        name: "{{ inventory_hostname }}"
        state: absent
        auto_remove: true

	- name: Remove dynamic molecule inventory
	  hosts: localhost
	  gather_facts: false
	  tasks:
	    - name: Remove dynamic inventory file
	      ansible.builtin.file:
	        path: "{{ molecule_ephemeral_directory }}/inventory/molecule_inventory.yml"
	        state: absent