[SOLVED] Verify that Ansible's Collection dependencies are installed before play begins

Verify that Ansible's Collection dependencies are installed before play begins

I use various Ansible Collections. When the Controller Node does not have them installed (e.g. because I installed ansible-core instead of ansible) then the play breaks halfway.

Is there a way to verify such dependencies before the play begins?

Solution

Unfortunately the command ansible-galaxy has no parameter to get clean output or to format it. So one need to do post-processing on the output.

 ansible-galaxy collection list 2>/dev/null | sed '0,/^-.*$/d;s/[ \t]*$//' | tr -s ' ' ','

To prevent using loop and in order to get all installed Ansible Collections for further processing, a minimal example playbook

---
- hosts: localhost
  become: false
  gather_facts: false

  tasks:

  - name: Generate Collection Facts
    shell:
      cmd: >-
        echo "Collection,Version";
        ansible-galaxy collection list 2>/dev/null
        | sed '0,/^-.*$/d'
        | sed 's/[ \t]*$//'
        | tr -s ' ' ','
    register: collection_facts

  - name: Show Collection Facts
    debug:
      msg: "{{ collection_facts.stdout | community.general.from_csv(dialect='unix') }}"

will create a list of Comma Separated Values (CSV) for further processing.

To get a clean list output

Drop Python warning messages according Is it possible to remove error messages from Bash?
Drop ansible-galaxy header from output according Remove all lines before a match with sed
Remove trailing whitespaces from output according How do I trim leading and trailing whitespace from each line of some output?
Replace whitespaces with comma according Replace spaces ...

Further Documentation

Regarding your comment

... it reports "what's installed". But if I want to know "what's missing" I need to perform more processing on that CSV output?

Right, depending on what one try to achieve more tests can and/or need to be done. A quick example

  - name: Register Collection Facts
    set_fact:
      collection_facts: "{{ collection_facts.stdout | community.general.from_csv(dialect='unix') }}"

  - name: Show Collection Facts
    debug:
      msg: "{{ collection_facts }}"

  - name: Show if 'community.general' is installed
    debug:
      msg: "Is installed"
    when: collection_facts | selectattr(search_key,'equalto',search_val) | list | count > 0
    vars:
      search_key: Collection
      search_val: community.general

Thanks To

Ansible check if key/value pair exists in list of dictionaries

How to proceed further?

There was a similar question in the past about What Ansible command to list or verify installed modules — whether built-in or add-on? which has a good solution to create a dictionary of installed collections and modules.