How to prevent Jinja2 substitution in Ansible - ansible

Question

I goal is to replace all the {{ and }} with {% raw %}{{ and }}{% endraw %} in all my markdown notes so that my hexo plugin won't attempt to template when rendering.
My code is:
- name: Get file list of post files
find:
paths: "{{ hexo_data_post_file_dir }}"
register: hexo_data_post_file_list
- name: Replace special char
replace:
path: "{{ item[0]['path'] }}"
regexp: "{{ item[1]['pattern'] }}"
replace: "{{ item[1]['string'] }}"
with_nested:
- "{{ hexo_data_post_file_list['files'] }}"
- - pattern: "{{ '{{' }}"
string: "{{ '{% raw %}{{' }}"
- pattern: "{{ '}}' }}"
string: "{{ '}}{% endraw %}' }}"
Despite I used "{{ '{{' }}" to ask jinja not to render {{, I still get error:
TASK [setup_docker_hexo : Replace special char] ********************************************************************************************************************************************
Tuesday 27 December 2022 11:58:56 +0800 (0:00:00.491) 0:00:13.572 ******
fatal: [uranus-debian]: FAILED! => {"msg": "template error while templating string: unexpected 'end of template'. String: {{. unexpected 'end of template'"}

Answer 1

Given the file
shell> cat test.txt.j2
{{ test_var }}
Declare the strings unsafe to block templating. For example,
my_files:
- "{{ playbook_dir }}/test.txt.j2"
my_regex:
- pattern: !unsafe '{{ '
string: !unsafe '{% raw %}{{ {% endraw %}'
- pattern: !unsafe ' }}'
string: !unsafe '{% raw %} }}{% endraw %}'
Test the expansion
- debug:
msg: "{{ item }}"
with_nested:
- "{{ my_files }}"
- "{{ my_regex }}"
gives
TASK [debug] *********************************************************************************
ok: [localhost] => (item=['/export/scratch/tmp7/test-117/test.txt.j2', {'pattern': '{{ ', 'string': '{% raw %}{{ {% endraw %}'}]) =>
msg:
- /export/scratch/tmp7/test-117/test.txt.j2
- pattern: '{{ '
string: '{% raw %}{{ {% endraw %}'
ok: [localhost] => (item=['/export/scratch/tmp7/test-117/test.txt.j2', {'pattern': ' }}', 'string': '{% raw %} }}{% endraw %}'}]) =>
msg:
- /export/scratch/tmp7/test-117/test.txt.j2
- pattern: ' }}'
string: '{% raw %} }}{% endraw %}'
Replace the patterns
- replace:
path: "{{ item.0 }}"
regexp: "{{ item.1.pattern }}"
replace: "{{ item.1.string }}"
with_nested:
- "{{ my_files }}"
- "{{ my_regex }}"
- debug:
msg: "{{ lookup('file', my_files.0) }}"
- debug:
msg: "{{ lookup('template', my_files.0) }}"
gives
TASK [debug] *********************************************************************************
ok: [localhost] =>
msg: '{% raw %}{{ {% endraw %}test_var{% raw %} }}{% endraw %}'
TASK [debug] *********************************************************************************
ok: [localhost] =>
msg: |-
{{ test_var }}
Declare the variable
my_file: "{{ playbook_dir }}/test.txt"
test_var: foo bar
and use the template
- template:
src: "{{ my_files.0 }}"
dest: "{{ my_file }}"
- debug:
msg: "{{ lookup('file', my_file) }}"
- debug:
msg: "{{ lookup('template', my_file) }}"
gives
TASK [debug] *********************************************************************************
ok: [localhost] =>
msg: '{{ test_var }}'
TASK [debug] *********************************************************************************
ok: [localhost] =>
msg: |-
foo bar
Notes
Example of a complete playbook for testing
- hosts: localhost
vars:
my_files:
- "{{ playbook_dir }}/test.txt.j2"
my_regex:
- pattern: !unsafe '{{'
string: !unsafe '{% raw %}{{{% endraw %}'
- pattern: !unsafe '}}'
string: !unsafe '{% raw %}}}{% endraw %}'
my_file: "{{ playbook_dir }}/test.txt"
test_var: foo bar
tasks:
- debug:
msg: "{{ item }}"
with_nested:
- "{{ my_files }}"
- "{{ my_regex }}"
- replace:
path: "{{ item.0 }}"
regexp: "{{ item.1.pattern }}"
replace: "{{ item.1.string }}"
with_nested:
- "{{ my_files }}"
- "{{ my_regex }}"
- debug:
msg: "{{ lookup('file', my_files.0) }}"
- debug:
msg: "{{ lookup('template', my_files.0) }}"
- template:
src: "{{ my_files.0 }}"
dest: "{{ my_file }}"
- debug:
msg: "{{ lookup('file', my_file) }}"
- debug:
msg: "{{ lookup('template', my_file) }}"
The playbook is not idempotent!