unable to parse ansible variable in jinja file using if condition - ansible

Question

I'm encountering below error while trying to pass ansible variable through if condition in jinja. (elsewhere I'm able to pass a string direclty and use the same condition in jinja and also able to read the ansible variable without any condition) Any leads please...
yaml extract
---
tasks:
- set_fact:
ansible_role: "role1"
- name: Create the Jinja2 based template
template: src=./source.j2 dest=./output.txt
source.j2
---
{% for role in roles %}
{% if {{ ansible_role }} == role.name %}
{% for item in role.tests %}
"{{ item }}"
{% endfor %}
{% endif %}
{% endfor %}
error
TASK [Create the Jinja2 based template]
***************************************
fatal: [localhost]: FAILED! => {"changed": false, "msg": "AnsibleError: template error while templating string: expected token
':', got '}'. String: ---\n{% for role in roles %}\n{% if {{
ansible_role }} == role.name %}\n{% for item in role.tests
%}\ninclude_controls \"{{ item }}\"\n{% endfor %}\n{% endif %}\n{%
endfor %}\n"}

Answer 1

Take some time to review the jinja2 template designer documentation. Your variable name is already inside a jinja2 expression. The double curly braces has to be used outside expressions to have the content of your variable written out, not inside an expression.
Therefore, you should change:
# !! WRONG !!
{% if {{ ansible_role }} == role.name %}
to
{% if ansible_role == role.name %}
My last 2 cent: don't prepend your own variable names with ansible_ as this is used by ansible itself for a lot of internal/magic variables and might lead to confusion.

Answer 2

I think the problem is in this line: {% if {{ ansible_role }} == role.name %}. When you use the {% %} notation, Jinja expects python inside. So you don't need to escape the ansible_role variable. Try it without it and see if now it works.