Ansible - how to make task fail based on specific output

Question

Hi I have a task which requires ftp a file from remote box to ansible controlled machine.I am using expect based FTP,so want the ansible to fail if file does not exist on the remote box.Following is my code. I am using a register variable.But i dont see the debug displaying the register contents.

     - name: copy files remote
       shell: |
         set timeout 1000
         spawn ftp {{ buildIP }}

         expect ":"
         send "{{ build_user }}\n"

    expect "ssword:"
    send "{{ build_password }}\n"

    expect "ftp>"
    send "get {{ build_path }} /root/Desktop/Sanity/{{  TID }}/{{ Image_dir }}/{{ build_filename }}\n"

    expect "ftp>"
    send "quit\n"

    set multiPrompt {[#$]}
    expect -re $multiPrompt
    exit 0
  args:
    executable: /usr/bin/expect
  register: shell_output
  tags: copy_source_code
- debug:
    var: shell_output.stdout_lines

Answer 1

I would recommend using get_url for fetching files from FTP instead of expect,It will show whether the task failed or succeeded in the play recap

example play:

---
- hosts: localhost
  tasks:
    - name: FTP Download
      get_url: url=ftp://username:password@localhost/file.zip dest=/tmp
      register: get_url_result

if the file is not present in the FTP server, output will be similar to this:

PLAY RECAP ********************************************************

localhost : ok=1 changed=0 unreachable=0
failed=1

In the task error details you can find the "not found" error as well