Jinja - How to use variable set in one file in another and set default

Question

I am new to jinja and need some help with doing the following:

main.tpl has the following content:

{%- with PREFIX = "test." %}
{%- set TEST_VARIABLE = "false" %}
{%- include "child1.tpl" %}
{%- endwith %}

How can I use TEST_VARIABLE in child1.tpl such that when it is false, I set a property like this to false else true:

{%- if {TEST_VARIABLE} == false %}
PROPERTY1=false
{%- else %}
PROPERTY1=true
{%- endif %}

I get and error saying unexpected '{' in field name.

Answer 1

There are two errors in your child1.tpl file. First, you are using invalid syntax to refer to a variable in your if statement. Second, you are comparing a string ("false") with a boolean variable (false). This won't do what you want. Fixing both of these issues gives you:

{%- if TEST_VARIABLE == "false" %}
PROPERTY1=false
{%- else %}
PROPERTY1=true
{%- endif %}

Using this and your main.tpl works without errors. Changing set TEST_VARIABLE = "false" to set TEST_VARIABLE = "something else" changes the final template output as expected.

---

With your original main.tpl and child1.tpl as above:

$ jinja2 main.tpl

PROPERTY1=false

If I modify main.tpl to look like:

{%- with PREFIX = "test." %}
{%- set TEST_VARIABLE = "something else" %}
{%- include "child1.tpl" %}
{%- endwith %}

Then I get:

$ jinja2 main.tpl

PROPERTY1=true