Extract value from output and send to next task

Question

I am trying to define a template in Ansible Tower, where I want to extract the id for the Active Controller in Kafka Broker and then use this value in another template / task that will perform the rolling restart but will make sure the active controller is started last

When I run this Ansible task

- name: Find active controller
  shell: '/bin/zookeeper-shell 192.168.129.227 get /controller'
  register: resultAC

I get the below result. I want to extract the brokerid and assign the value of 2 to a variable that can be used in a different task in the same template or pass it to another template when the templates are part of a workflow definition.

I tried using resultAC.stdout_lines[5].brokerid but that does not work.

The structure of resultAC:

{
    "resultAC": {
        "stderr_lines": [],
        "changed": true,
        "end": "2020-08-19 07:36:01.950347",
        "stdout": "Connecting to 192.168.129.227\n\nWATCHER::\n\nWatchedEvent state:SyncConnected type:None path:null\n{\"version\":1,\"brokerid\":2,\"timestamp\":\"1597241391146\"}",
        "cmd": "/bin/zookeeper-shell 192.168.129.227 get /controller",
        "failed": false,
        "delta": "0:00:02.843972",
        "stderr": "",
        "rc": 0,
        "stdout_lines": [
            "Connecting to 192.168.129.227",
            "",
            "WATCHER::",
            "",
            "WatchedEvent state:SyncConnected type:None path:null",
            "{\"version\":1,\"brokerid\":2,\"timestamp\":\"1597241391146\"}"
        ],
        "start": "2020-08-19 07:35:59.106375"
    },
    "_ansible_verbose_always": true,
    "_ansible_no_log": false,
    "changed": false
}

β.εηοιτ.βε · Accepted Answer · 2020-08-19T19:51:45.093

Because your JSON is just part of a list of strings, it is not parsed or considered as a JSON.
You will have to use the Ansible filter from_json in order to parse it back to a dictionary.

Given the playbook:

- hosts: all
  gather_facts: no
  vars: 
    resultAC:
      stdout_lines: 
        - "Connecting to 192.168.129.227"
        - ""
        - "WATCHER::"
        - ""
        - "WatchedEvent state:SyncConnected type:None path:null"
        - "{\"version\":1,\"brokerid\":2,\"timestamp\":\"1597241391146\"}"
      
  tasks:
    - debug: 
        msg: "{{ (resultAC.stdout_lines[5] | from_json).brokerid }}"

This gives the recap:

PLAY [all] *************************************************************************************************************************************************************

TASK [debug] ***********************************************************************************************************************************************************
ok: [localhost] => {
    "msg": "2"
}

PLAY RECAP *************************************************************************************************************************************************************
localhost                  : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Going further, maybe I would select and match the JSON in the stdout_lines list, just in case it is not always at the sixth line:

- hosts: all
  gather_facts: no
  vars: 
    resultAC:
      stdout_lines: 
        - "Connecting to 192.168.129.227"
        - ""
        - "WATCHER::"
        - ""
        - "WatchedEvent state:SyncConnected type:None path:null"
        - "{\"version\":1,\"brokerid\":2,\"timestamp\":\"1597241391146\"}"
      
  tasks:
    - debug: 
        msg: "{{ (resultAC.stdout_lines | select('match','{.*\"brokerid\":.*}') | first | from_json).brokerid }}"

Thanks. I will try it soon. How do I use this value as a variable in another task or pass it on to a template in the workflow? — adbdkb, Aug 20 '20 at 23:30
This worked. How do I assign it to a variable and use it later? Thanks — adbdkb, Aug 22 '20 at 11:15

Extract value from output and send to next task

1 Answers1