Why does to_nice_yaml produce quotes around the result in Jinja2 (Ansible)?

I have the following setup.

my_var has the following value.

  ansible_facts:
    discovered_interpreter_python: /usr/bin/python
  invocation:
    module_args:
      api_key: null
      api_version: v1
      ca_cert: null
      client_cert: null
      client_key: null
      context: null
      field_selectors: []
      host: null
      kind: Secret
      kubeconfig: null
      label_selectors: []
      password: null
      proxy: null
      username: null
      validate_certs: null
  resources:
  - apiVersion: v1
    data:
      a: blah
      b: blah
      c: blah
    kind: Secret
    metadata:
      name: my_name
    type: Opaque

I am using this in a task with a template like this.

- name: "doh"
  k8s:
    state: present
    namespace: "doh"
    definition: "{{ lookup('template', 'template.j2') }}"

My template looks like this.

apiVersion: v1
data: "{{ my_var | json_query("resources[?metadata.name=='" + my_name + ".my_string." + some_var + "'].data") | first | to_nice_yaml }}"
kind: Secret
metadata:
  name: "blah"
type: Opaque

Unluckily I get this as a result. This is a string and should be plain yaml.

apiVersion: v1
data: "a: blah <-- quote, why?
b: blah
c: blah
" <-- quote, why?
kind: Secret
metadata:
  name: "blah"
type: Opaque

Why am I getting quotes around my yaml in Jinja2 and how do I avoid it?

Solution

In your template, there are quotes around the yaml:

data: "{{ ... | to_nice_yaml }}"

These quotes are part of your template and will be part of the rendered output.

I think you're confusing Ansible syntax with jinja2 template syntax (likely based on this gotcha from the docs).

This gotcha is not true for jinja2 templates. Everything that is not inside a jinja2 delimited block ({%, {{, etc.) will translate to the rendered value.

If you don't want the quotes in the rendered value, just take them out of the template.