In this blog, we will explore how to parse json output in Ansible and use set_fact for variable creation based on the json output

If you want to see the video for this article, click here

Problem Statement:

• You have an application where you want to make an api call to search for a particular group and depending on the result you want to run your playbook or set some variables

Solution:

• Write a playbook to search for the group “test_group”
• Use “uri” module to interact with your webservices (http/https)
• Registering variable: When you execute a task and save the return value in a variable for use in later tasks, you create a registered variable.
• force_basic_auth: Force the sending of the Basic authentication header upon initial request.The library used by the uri module only sends authentication information when a webservice responds to an initial request with a 401 status. Since some basic auth services do not properly send a 401, logins will fail.
• debug: prints statements during execution and can be useful for debugging variables or expressions without necessarily halting the playbook.
• ignore_errors: You set this as true if you want playbook to continue run subsequent tasks and doesn’t fail the playbook

Ansible Playbook

#search group if exist 
- name: Search if it exit
  uri:
    url: "http://{{hostname}}/api/user_groups/search?q=test_group"
    method: GET
    user: "username"
    password: "password"
    force_basic_auth: yes
    return_content: yes
    headers:
        Content-Type: "application/json"
  ignore_errors: true
  register: result

- debug:
    msg: "{{result}}"

- debug: 
    msg: "{{ result.json | list }}"

Sample JSON Output

• This is the sample output from my application when I execute the above playbook

"msg": {
        "changed": false,
        "msg": "All items completed",
        "results": [
            {
               
                "content": "{\"paging\":{\"pageIndex\":1,\"pageSize\":100,\"total\":1},\"groups\":[{\"id\":11760,\"name\":\"test_group\",\"membersCount\":3,\"default\":false}]}",
                
                "content_type": "application/json",
                
                "json": {
                    "groups": [
                        {
                            "default": false,
                            "id": 11760,
                            "membersCount": 3,
                            "name": "test_group"
                        }
                    ],
                    "paging": {
                        "pageIndex": 1,
                        "pageSize": 100,
                        "total": 1
                    }
                }
                
        }
        ]
    }

• paging.total —gives me the count of group
• set_fact: allow setting new variables
• Based on the count you can call other tasks/playbook etc
• Below is the example of how you can write a playbook using set_fact and filter the json data using ‘from_json’

- set_fact: total_count="{{ result.content | from_json | json_query('paging.total')}}"

- include: sentemail.yml 
  when: total_groups == '0'
  ignore_errors: true

• If group is exist and you want to fetch the group name

- set_fact: group_name="{{ result.content | from_json | json_query('groups[0].name')}}"

• Check this link for more examples of filtering in json

Congratulations, you have successfully learnt how to parse json output in Ansible and use set_fact for variable creation.