Ansible | Process data which can be either JSON or YAML - json

Question

I'm using Ansible to read a config, which can be either JSON or YAML and extract values from some of the nodes in the file.
I know I can use from_json or from_yaml to process it in Ansible, but since I don't know which format the config will be in, I'm having difficulty making it work.
The file is Kubernetes' Kubeconfig. Examples below:
in YAML
apiVersion: v1
clusters:
- cluster:
certificate-authority-data: REDACTED
server: https://my-k8s-cluster.com
name: k8s-clstr-master
contexts:
- context:
cluster: k8s-clstr-master
namespace: kube-system
user: k8s-clstr-master-admin
name: k8s-clstr-master
current-context: k8s-clstr-master
kind: Config
preferences: {}
users:
- name: k8s-clstr-master-admin
user:
client-certificate-data: REDACTED
client-key-data: REDACTED
in JSON
{
"kind": "Config",
"apiVersion": "v1",
"preferences": {},
"clusters": [
{
"name": "k8s-clstr-master",
"cluster": {
"server": "https://my-k8s-cluster.com",
"certificate-authority-data": "REDACTED"
}
}
],
"users": [
{
"name": "k8s-clstr-master-admin",
"user": {
"client-certificate-data": "REDACTED",
"client-key-data": "REDACTED"
}
}
],
"contexts": [
{
"name": "k8s-clstr-master",
"context": {
"cluster": "k8s-clstr-master",
"user": "k8s-clstr-master-admin",
"namespace": "kube-system"
}
}
],
"current-context": "k8s-clstr-master"
}
Ansible I'm using:
vars:
kubeconfig: "{{ lookup('hashivault', '/kubeconfig/admin', 'config') }}"
tasks:
- name: Find cluster server name
shell: "echo {{ kubeconfig.clusters[0].cluster.server }}"
Above Ansible block will work okay if kubeconfig is retrieved in JSON format, but it will fail if it's retrieved as in YAML format.
I might be able to make a task with |from yaml and then add ignore_errors: true, but that just doesn't feel like right way of doing it.
Anyone has any tips for me on how I can approach this problem?

Answer 1

There are some built-in tests in Jinja2.
The way Ansible templator works if you have JSON string inside {{...}} expression, it is automatically converted to object. So if you fetch JSON from your vault, kubeconfig becomes object, otherwise it is a string.
Here's a recipe for you:
vars:
kubeconfig_raw: "{{ lookup('hashivault', '/kubeconfig/admin', 'config') }}"
kubeconfig: "{{ kubeconfig_raw if kubeconfig_raw is mapping else kubeconfig_raw | from_yaml }}"
tasks:
- name: Find cluster server name
shell: "echo {{ kubeconfig.clusters[0].cluster.server }}"

Answer 2

If you use the include_vars task, it does not matter which format you provide. The task accepts both.
---
- hosts: localhost
connection: local
tasks:
- include_vars:
file: config
name: kubeconfig
- debug: var=kubeconfig