How to use filter on a nested jinja2 template

Question

I have 2 templates in my Ansible playbook:

template-1.yaml.j2:

{
    "auths": {
        "https://index.docker.io/v1/": {
            "auth": {{ (user.name + ':' + user.pass) | b64encode }}
        }
}

template-2.yaml.j2:

---
apiVersion: v1
data:
  .dockerconfigjson: '{% include "template-1.yaml.j2" %}'
kind: Secret
metadata:
  name: pull-secret
  namespace: default
type: kubernetes.io/dockerconfigjson

The nested template works great, but I want template-2.yaml.j2 to encode template-1.yaml.j2 in base64, I tried adding a filter like so:

{% include "template-1.yaml.j2" | b64encode %}

And it fails with the following error:

An unhandled exception occured while running the lookup plugin 'template'. Error was a <class 'jinja2.exceptions.TemplateNotFound'>, original message: dGVtcGxhdGUtMi55YW1sLmoy

What actually happens is that the literal string template-2.yaml.j2 is encoded and fails.

Is there any solution beside separating the templates to different tasks in my Ansible playbook?

Answer 1

Simply replace the following line (wrong):

.dockerconfigjson: '{% include "template-1.yaml.j2" | b64decode %}'

with (right):

.dockerconfigjson: '{{ lookup("template", "template-1.yaml.j2") | b64encode }}'

The template lookup will fetch the result of the given template as a string which can then be passed to the b64encode filter