Ansible regex starting from position x up to pos y

Question

I have the following problem. I need to extract the File ID from the following output of a playbook:

"result_task_id": {
        "changed": false,
        "dnac_response": {
            "response": {
                "endTime": 1674734268584,
                "id": "12393650-c412-4f09-bcc6-25fe24b8b0a9",
                "instanceTenantId": "6305975890949b5614356b66",
                "isError": false,
                "lastUpdate": 1674734268584,
                "progress": "{\"fileId\":\"1ce07c2a-c3f9-46f3-b216-713d043871d6\"}",
                "rootId": "12393650-c412-4f09-bcc6-25fe24b8b0a9",
                "serviceType": "Command Runner Service",
                "startTime": 1674734268134,
                "username": "admin",
                "version": 1674734268584
            },
            "version": "1.0"
        },
        "failed": false,
        "result": ""
    }
}

Selecting the right field result_task_id.dnac_response.response.progress results in this output:

{\"fileId\":\"1ce07c2a-c3f9-46f3-b216-713d043871d6\"}

I just need the ID 1ce07c2a-c3f9-46f3-b216-713d043871d6. The ID itself can differ from run to run but the position will be the same.

Is there a way to use the select('match'...) in order to filter it out?

I need characters 14 until 49. I was not able to find the right regex.

Thanks for the help

score 1 · Answer 1 · answered Jan 26 '23 at 16:34

The output of the playbook is a valid JSON. Given the data in a string

  out_str: |
    {
    "result_task_id": {
        "changed": false,
        "dnac_response": {
            "response": {
                "endTime": 1674734268584,
                "id": "12393650-c412-4f09-bcc6-25fe24b8b0a9",
                "instanceTenantId": "6305975890949b5614356b66",
                "isError": false,
                "lastUpdate": 1674734268584,
                "progress": "{\"fileId\":\"1ce07c2a-c3f9-46f3-b216-713d043871d6\"}",
                "rootId": "12393650-c412-4f09-bcc6-25fe24b8b0a9",
                "serviceType": "Command Runner Service",
                "startTime": 1674734268134,
                "username": "admin",
                "version": 1674734268584
            },
            "version": "1.0"
        },
        "failed": false,
        "result": ""
        }
    }

Convert it to a dictionary

  out: "{{ out_str|from_yaml }}"

gives

  out:
    result_task_id:
      changed: false
      dnac_response:
        response:
          endTime: 1674734268584
          id: 12393650-c412-4f09-bcc6-25fe24b8b0a9
          instanceTenantId: 6305975890949b5614356b66
          isError: false
          lastUpdate: 1674734268584
          progress: '{"fileId":"1ce07c2a-c3f9-46f3-b216-713d043871d6"}'
          rootId: 12393650-c412-4f09-bcc6-25fe24b8b0a9
          serviceType: Command Runner Service
          startTime: 1674734268134
          username: admin
          version: 1674734268584
        version: '1.0'
      failed: false
      result: ''

Get the attribute progress

  progress: "{{ out.result_task_id.dnac_response.response.progress }}"

gives

  progress:
    fileId: 1ce07c2a-c3f9-46f3-b216-713d043871d6

Finally, get the value of fileId

  fileId: "{{ progress.fileId }}"

gives

  fileId: 1ce07c2a-c3f9-46f3-b216-713d043871d6

^{Example of a complete playbook for testing
- hosts: localhost

vars:

out_str: |
{
"result_task_id": {
"changed": false,
"dnac_response": {
"response": {
"endTime": 1674734268584,
"id": "12393650-c412-4f09-bcc6-25fe24b8b0a9",
"instanceTenantId": "6305975890949b5614356b66",
"isError": false,
"lastUpdate": 1674734268584,
"progress": "{\"fileId\":\"1ce07c2a-c3f9-46f3-b216-713d043871d6\"}",
"rootId": "12393650-c412-4f09-bcc6-25fe24b8b0a9",
"serviceType": "Command Runner Service",
"startTime": 1674734268134,
"username": "admin",
"version": 1674734268584
},
"version": "1.0"
},
"failed": false,
"result": ""
}
}
out: "{{ out_str|from_yaml }}"

progress: "{{ out.result_task_id.dnac_response.response.progress }}"
fileId: "{{ progress.fileId }}"

tasks:

- debug:
var: out
- debug:
var: progress
- debug:
var: fileId}

score 0 · Answer 2 · answered Jan 26 '23 at 15:32

That was the solution:

  - name: Set File ID
    ansible.builtin.set_fact:
      file_id_list: "{{ result_task_id.dnac_response.response.progress.splitlines()| map ('from_json') }}"
  - debug: var=file_id_list

  - name: Set File ID
    ansible.builtin.set_fact:
      file_id: "{{ file_id_list[0].fileId }}"
  - debug: var=file_id

U880D · Answer 3 · 2023-01-27T18:49:55.500

Regarding

... from position x to y ... I need characters 14 until 49.

you may have a look into Python slicing.

The minimal example

---
- hosts: localhost
  become: false
  gather_facts: false

  vars:

    STRING: '{\"fileId\":\"1ce07c2a-c3f9-46f3-b216-713d043871d6\"}'

  tasks:

  - name: Show slice
    debug:
      msg: "{{ STRING[14:50] }}"

will result into an output of

TASK [Show slice] *************************
ok: [localhost] =>
  msg: 1ce07c2a-c3f9-46f3-b216-713d043871d6

Please notice that such kind of "magic numbers" are a bad practice in programming, as well that kind of hard coding in data structures. Therefore, maintaining a data structure as shown in the other answer given here should be preferred.

Regarding

Is there a way to use the select('match'...) in order to filter it out? ... I was not able to find the right regex.

it seems your use case would be Searching for UUIDs in text with regex. Therefore

  - name: Show UUID
    debug:
      msg: "{{ STRING | regex_search('[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}') }}"

will result into the required output.

Ansible regex starting from position x up to pos y

3 Answers3

Linked