How to tail the logs of long running python script invoked via ansible

Question

We are running a python script via ansible. The script takes around 45 mins to complete and the logging is in verbose mode. But the issue is we get to know the result only after 45 minutes or if the script fails.

- name: Run a python script
  shell: |
    cd /tmp/
    python {{script_name}} {{branch}} {{ script_action_arg_test }} >>  output.txt

I have tried the above approach, the python process keeps running but does not log anything to output.txt Is there a way to capture the verbose logs of the script in ansible itself?

Answer 1

OK -- it's ugly. BUT, Ansible is for automation -- fire and forget, and is not designed for people to see what's going on in real time.

Now, use ansible-galaxy init my-cool-role in your roles directory to create the role. Then, these are the files you will put in the role:

tasks/main.yml:

---
- name: Copy script to remote host
  copy:
    src: long_script.sh
    dest: long_script.sh
    mode: 0755

- name: Run script in async
  shell: ./long_script.sh > long_script.out
  async: 1000
  poll: 0
  register: long_task

- name: Include monitoring tasks
  include_tasks: monitor.yml
  loop: "{{ range(0, 100, 1)|list }}"

tasks/monitor.yml

---
- set_fact:
    done: "{{ 'DONE' == tail.stdout_lines[9] | default(false) }}"

- debug:
    var: tail.stdout_lines[9]

- debug:
    var: done

- meta: end_play
  when: done|bool

- name: Get last ten lines
  shell: sleep 5; tail long_script.out
  register: tail

- name: Show lines
  debug:
    var: tail.stdout_lines

files/long_script.sh:

#!/bin/bash
for (( ii=0; ii<50; ii++ )); do
  echo -n "$ii: "
  date
  sleep 1
done
echo DONE

   

This assumes that the long task is the last thing you're doing, because it ends the play. Note that you have to have enough loops to cover the expected time it il take the task to run. If you need to do something after this, just put another play in the playbook. Good luck.