ansible set_fact to the list with jinja2 condition - ansible

Question

I'd like to set a common_apt_packages list based on OS distribution, so I've used jinja2 if condition as the script below, but the return common_apt_packages type is AnsibleUnsafeText
- hosts: localhost
vars:
common_apt_packages_ubuntu_22_04:
- ack-grep
- acl
- apt-transport-https
- build-essential
- dstat
- git-core
- htop
- iftop
- iotop
tasks:
- name: Set common_apt_packages for ubuntu {{ ansible_distribution_version }}
set_fact:
common_apt_packages: "{% if ansible_distribution_version =='22.04' %} {{ common_apt_packages_ubuntu_22_04 }} {% else %} {{ common_apt_packages_ubuntu_18_04 }} {% endif %}"
How can I improve the script to return common_apt_packages as a List variable?

Answer 1

Just remove the white spaces between %} {{ and }} {%, because Ansible will then handle it as a string, not as a list.
With type_debug you can get the output type.
- hosts: localhost
vars:
common_apt_packages_ubuntu_22_04:
- ack-grep
- acl
common_apt_packages_ubuntu_18_04:
- vim
- nano
tasks:
- name: Set common_apt_packages for ubuntu {{ ansible_distribution_version }}
set_fact:
common_apt_packages_without_spaces: "{% if ansible_distribution_version =='22.04' %}{{ common_apt_packages_ubuntu_22_04 }}{% else %}{{ common_apt_packages_ubuntu_18_04 }}{% endif %}"
- name: Set common_apt_packages for ubuntu {{ ansible_distribution_version }}
set_fact:
common_apt_packages_with_spaces: "{% if ansible_distribution_version =='22.04' %} {{ common_apt_packages_ubuntu_22_04 }} {% else %} {{ common_apt_packages_ubuntu_18_04 }} {% endif %}"
- debug:
msg: "{{ common_apt_packages_without_spaces }} ==> {{ common_apt_packages_without_spaces | type_debug }}"
- debug:
msg: "{{ common_apt_packages_with_spaces }} ==> {{ common_apt_packages_with_spaces | type_debug }}"
TASK [Set common_apt_packages for ubuntu 20.04] ************
ok: [localhost]
TASK [debug] ***********************************************
ok: [localhost] => {
"msg": "['vim', 'nano'] ==> list"
}
TASK [debug] ***********************************************
ok: [localhost] => {
"msg": " ['vim', 'nano'] ==> AnsibleUnsafeText"
}
When you try to install them using the apt module:
# without white spaces
"package": [
"vim",
"nano"
]
# with white spaces
"package": [
" ['vim'",
" 'nano'] "
]
"msg": "No package(s) matching '['vim'' available"

Answer 2

Create the lists. For example in group_vars
shell> cat group_vars/all/packages.yml
list_of_packages_for_18_04: [pkg1_18_04, pkg2_18_04, pkg3_18_04]
list_of_packages_for_20_04: [pkg1_20_04, pkg2_20_04, pkg3_20_04]
list_of_packages_for_22_04: [pkg1_22_04, pkg2_22_04, pkg3_22_04]
default_list_of_packages: [pkg1, pkg2, pkg3]
and put the lists of the packages into a dictionary. For example,
- hosts: localhost
vars:
packages:
'18.04': "{{ list_of_packages_for_18_04 }}"
'20.04': "{{ list_of_packages_for_20_04 }}"
'22.04': "{{ list_of_packages_for_22_04 }}"
'default': "{{ default_list_of_packages }}"
my_packages: "{{ packages[ansible_distribution_version]|
default(packages.default) }}"
tasks:
- debug:
var: ansible_distribution_version
- debug:
var: my_packages
gives (abridged)
TASK [debug] ******************************************************
ok: [localhost] =>
ansible_distribution_version: '20.04'
TASK [debug] ******************************************************
ok: [localhost] =>
my_packages:
- pkg1_20_04
- pkg2_20_04
- pkg3_20_04
Your problem is that output of Jinja is always a string. Ansible should convert it automatically if it is a valid YAML. If you for whatever reason have to use Jinja create the string first and convert it to YAML explicitly. For example,
- set_fact:
packages_str: |
{% if ansible_distribution_version == '22.04' %}
{{ common_apt_packages_ubuntu_22_04 }}
{% else %}
{{ common_apt_packages_ubuntu_18_04 }}
{% endif %}"
- set_fact:
packages: "{{ packages_str|from_yaml }}"
You can't put the declarations into a single set_fact because the second declaration knows nothing about the first one. But, you can put them into any vars, of course.
Test of the conversion in Ansible 2.12.9 Python 3.8.5, and Jinja 3.0.1
- hosts: localhost
vars:
packages_str: |
{% if ansible_distribution_version == '20.04' %}
{{ list_of_packages_for_20_04 }}
{% else %}
{{ list_of_packages_for_18_04 }}
{% endif %}
packages: "{{ packages_str|from_yaml }}"
tasks:
- debug:
var: ansible_distribution_version
- debug:
var: packages_str|type_debug
- debug:
var: packages|type_debug
- debug:
var: packages_str
- debug:
var: packages
gives (abridged)
TASK [debug] **************************************************
ok: [localhost] =>
ansible_distribution_version: '20.04'
TASK [debug] **************************************************
ok: [localhost] =>
packages_str|type_debug: list
TASK [debug] **************************************************
ok: [localhost] =>
packages|type_debug: list
TASK [debug] **************************************************
ok: [localhost] =>
packages_str:
- pkg1_20_04
- pkg2_20_04
- pkg3_20_04
TASK [debug] **************************************************
ok: [localhost] =>
packages:
- pkg1_20_04
- pkg2_20_04
- pkg3_20_04