Add "break_when" to the "loop_control"

[taraspos]

SUMMARY

Add the ability to break the loop conditionally.

ISSUE TYPE

• Feature Idea

COMPONENT NAME

core

ADDITIONAL INFORMATION

- set_fact:
       array: ["1", "2", "3", "stop here", "33333333" ]

- debug:
      var: item
   loop: "{{ array }}"
   loop_control:
       break_when: '{{ item }} == "stop here"'

[samdoran]

This could be added to the proposals on improving loops:

• Ansible loop interface redesign proposals#140
• Improve loop UI proposals#99

[bcoca]

you already can 'kindof' do this via existing when:, using the registered var and previous item state

[jgibart]

It is currently very hard to have error control on tasks in loop.
You can not stop loop until end even when a task in the loop is in error

I dont see how you can do what the previous comment suggesst :
You may access the previous item state and skip item after the failed one , but what about the other items after ?

I'm trying to implement a script to perform rolling restart or clustered services.
The idea is to restart services one by one but to stop immediately when a service fails, so that we dont shutdown another healthy server in case the new binary doesnt work.

The "intelligence" of starting and declaring the service up or down is delegated to a script. Basically this script attempts to start a systemd service and then run a sanity test just after. In case of failure it fails ( exits 1).

In order to serialize just the servers restart I used an pattern in a delegating loop

- name: "ensure service '{{service}}'  started (run task host by host) "
  become: yes
  become_method: sudo
  script:  "secure_start.py  --service {{ service }}   --state {{ 'restarted' if   binary.changed   else 'started' }}"
  when: hostitem in deployments[service] 
  delegate_to: "{{ hostitem }}"
  register: testout
  changed_when: "testout.stdout | from_json|json_query('changed')"
  with_items: "{{ groups['applicative'] }}"
  loop_control:
    loop_var: hostitem
  run_once: true

The problem with this pattern is that if restart on host 1 fails the restart is still attempted on host 2
and only when the loop is complete the task is marked failed.

I'd like the loop to stop at first error.

Is it possible to implement a break_when condition to stop loop ? Here for example :
break_when: testout.failed

I didnt find an easy workaround for this issue.

Thank you.

[bcoca]

mostly implemented in #62151

[bcoca]

waiting_on_contributor

[ansibot]

Thank you very much for your submission to Ansible. It means a lot to us that you've taken time to contribute.

Unfortunately, this issue has been open for some time while waiting for a contributor to take it up but there does not seem to have been anyone that did so. So we are going to close this issue to clear up the queues and make it easier for contributors to browse possible implementation targets.

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