using Jinja2 template to copy content in a file with Anisible

I would jinja2 template to copy some contents in a file depending on the distribution_major_version. So i am using if statement to achieve the goal. I have this file /mytemplates/foo.j2 Could you please confirm if this is the best practice to write the conditional statement or not?


{% if ansible_facts['distribution_major_version'] == "6" %}
    line1
    line2
    line3

{% elif ansible_facts['distribution_major_version'] == "7" or ansible_facts['distribution_major_version'] == "8"%}
    
    line1 
    line4
    line6

{% endif %}

Solution

Put the data into a dictionary. For example,

    lines:
      '6': |
        line1
        line2
        line3
      '7': |

        line1
        line4
        line6
      '8': |

        line1
        line4
        line6

Then, the template is trivial

shell> cat templates/lines.txt.j2
{{ lines[ansible_distribution_major_version] }}

^{Example of a complete playbook for testing
shell> cat pb.yml
- hosts: localhost
vars:
lines:
'6': |
line1
line2
line3
'7': |

line1
line4
line6
'20': |

line1
line4
line20
tasks:
- debug:
var: ansible_distribution_major_version
- template:
src: lines.txt.j2
dest: lines.txt

gives
shell> ansible-playbook pb.yml

PLAY [localhost] *****************************************************************************

TASK [Gathering Facts] ***********************************************************************
ok: [localhost]

TASK [debug] *********************************************************************************
ok: [localhost] =>
ansible_distribution_major_version: '20'

TASK [template] ******************************************************************************
changed: [localhost]

PLAY RECAP ***********************************************************************************
localhost: ok=3 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0

shell> cat lines.txt

line1
line4
line20

Notes

You can use

ansible_distribution_major_version

instead of
ansible_facts['distribution_major_version']

You don't need the bracket notation. You can reference the attribute in dot notation

ansible_facts.distribution_major_version}