Extract value from output and send to next task - ansible

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
}

Answer 1

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 }}"