Read a JSON file into a variable - Ansible lookup plugin file

How to automate the reading of example.json file on Ansible host, assign to a variable and use in your Ansible Playbook code.

How to Read a JSON file into a variable on the host with Ansible?

The JSON (JavaScript Object Notation) is an open standard file format used a lot for data interchange.

I'm going to show you a live Playbook with some simple Ansible code.

I'm Luca Berton, and welcome to today's episode of Ansible Pilot.

Ansible reads a JSON file into a variable

ansible.builtin.file - read file contents

from_json filter - converts the variable to JSON.

Let's dive deep into the Ansible lookup plugin file.

Plugins are a way to expand the Ansible functionality. With lookup plugins specifically, you can load variables or templates with information from external sources.

The full name is ansible.builtin.file; it's part of ansible-core and is included in all Ansible installations.

The purpose of the file lookup plugin is to read file contents.

The "from_json" is an Ansible-specific filter to convert the input to JSON.

Let's combine the result of the file lookup plugin with the from_json filter for our use case.

Playbook

How to read the example.json JSON file, assign it to a variable and use it in your Ansible Playbook code.

code

example.json

``json


{
  "name": "John",
  "age": 30
}



read_json.yml

`yaml


---
name: json read Playbook
  hosts: localhost
  vars:
    jsondata: "{{ lookup('file', 'example.json') | from_json }}"
  tasks:
    - name: Print variable
      ansible.builtin.debug:
        var: jsondata



execution

`bash


$ ansible-playbook read_json.yml 
[WARNING]: No inventory was parsed, only implicit localhost is available
[WARNING]: provided hosts list is empty, only localhost is available. Note that the
implicit localhost does not match 'all'
PLAY [json read Playbook] *
TASK [Gathering Facts] 
ok: [localhost]
TASK [Print variable] *
ok: [localhost] => {
    "jsondata": {
        "age": 30,
        "name": "John"
    }
}
PLAY RECAP **
localhost                  : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0



idempotency

``bash

$ ansible-playbook read_json.yml

[WARNING]: No inventory was parsed, only implicit localhost is available

[WARNING]: provided hosts list is empty, only localhost is available. Note that the

implicit localhost does not match 'all'

PLAY [json read Playbook] *

TASK [Gathering Facts]

ok: [localhost]

TASK [Print variable] *

ok: [localhost] => {

"jsondata": {

"age": 30,

"name": "John"

}

PLAY RECAP *