ansibleansible-2.xansible-runner

Why does the result from the shell module in Ansible contain the dictionary twice when I print result?

I'm trying to execute a shell script on a localhost using Ansible and display the output of the script. I've registered the output of the command using the shell module and stored it in the result variable. When I print result using the debug module, I see the dictionary duplicated. The dictionary contains both the stdout and stdout_lines fields, but I don't understand why the result is duplicated. Here's the playbook I'm using:

yaml

---
- name: Run shell script and display all keys in result
  hosts: localhost
  tasks:
    - name: Create the shell script
      copy:
        dest: /tmp/multi_output.sh
        content: |
          #!/bin/bash
          # Print multiple messages to STDOUT
          for i in {1..101}
          do
              echo "Message $i to STDOUT"
          done
          sync  # Forces the buffer to be written to disk
        mode: '0755'

    - name: Run the shell script
      shell: "/tmp/multi_output.sh"
      register: result
      environment:
        PYTHONUNBUFFERED: 1
        
    - name: Display unique lines from 'stdout_lines'
      debug:
        var: result.stdout_lines
      changed_when: false

    - name: Display all keys in 'result'
      debug:
        var: result

Question: Why do I see two similar entries when I print result, as if the dictionary is duplicated (e.g., the stdout and stdout_lines fields)? How can I avoid this behavior and get a clear display of the output?

TASK [Visualizzare tutte le chiavi di 'result'] ********************************
ok: [localhost] => {
    "result": {
        "changed": true,
        "cmd": "/tmp/multi_output.sh",
        "delta": "0:00:00.016129",
        "end": "2025-03-19 17:17:17.259092",
        "failed": false,
        "msg": "",
        "rc": 0,
        "start": "2025-03-19 17:17:17.242963",
        "stderr": "",
        "stderr_lines": [],
        "stdout": "....",
        "stdout_lines": [
            "Messaggio 1 su STDOUT",
            "Messaggio 2 su STDOUT",
            "Messaggio 82 su STDOU"
}

ok: [localhost] => {
    "result": {
        "changed": true,
        "cmd": "/tmp/multi_output.sh",
        "delta": "0:00:00.016129",
        "end": "2025-03-19 17:17:17.259092",
        "failed": false,
        "msg": "",
        "rc": 0,
        "start": "2025-03-19 17:17:17.242963",
        "stderr": "",
        "stderr_lines": [],
        "stdout": "....",
        "stdout_lines": [
            "Messaggio 1 su STDOUT",
            "Messaggio 2 su STDOUT",
            "Messaggio 3 su STDOUT"
        ]
    }
}

TASK [Visualizzare tutte le chiavi di 'result'] ********************************
ok: [localhost] => {
    "result": {
        "changed": true,
        "cmd": "/tmp/multi_output.sh",
        "delta": "0:00:00.016129",
        "end": "2025-03-19 17:17:17.259092",
        "failed": false,
        "msg": "",
        "rc": 0,
        "start": "2025-03-19 17:17:17.242963",
        "stderr": "",
        "stderr_lines": [],
        "stdout": "...",
        "stdout_lines": [
            "Messaggio 1 su STDOUT",
            "Messaggio 2 su STDOUT",
            "Messaggio 3 su STDOUT"
        ]
    }
}
Solution

  • The issue was resolved by updating the versions of the libraries to:

    These versions are not the latest because I need to maintain compatibility with CentOS 7 systems running Python 2.7.

    With this configuration, the issue no longer occurs.