Hero Image
- IronicBadger

Ansible Tip - Using the expect module

Another Ansible top tip. Suppose you are running an installer or other process via Ansible which expects the user to be present accept a license agreement, enter some information or something. Enter expect, a handy little utility which can listen for certain strings in stdout and react accordingly.

- name: expect example
    echo: yes
    chdir: "{{ dir }}"
    command: "./{{ exectuable_filename }}"
    timeout: "{{ timeout }}"
      (.*)Please enter your name(.*): "Fred"
      (.*)Please enter your age(>*): "37"
      (.*)db port(.*): "{{ db_port }}"
      (.*)db user(.*): "{{ db_user }}"
      (.*)db pass(.*): "{{ db_pass }}"
    register: expect_example_result
    failed_when: "expect_example_result.rc != 0 and 'Success' not in expect_example_result.stdout"

The responses can be parameterised via variables or hard coded. We can also see that using the failed_when option it is easily possible to react to specific events and fail on certain conditions.