Feature: Allow until-loops on blocks or includes

[dagwieers]

SUMMARY

It would be quite useful if you can loop over more than one single tasks.

For instance if you have to poll a remote system for some progress and at the same time you want to push this progress to another backend, you could be doing:

- hosts: localhost
  tasks:
  - name: Start a long-running task
    uri:
      url: https://some-service/v1/put/new_job
      body: { foo: bar }
    register: new_job

  - until: job_status.json.message in ['Finished', 'Failed']
    block:
    - name: Get job status
      uri:
        url: https://some-service/v1/get/new_job
      register: job_status

    - name: Report job status to web service
      uri:
        url: https://backend-system/v1/post/job_status
        body: '{{ job_status.json }}'

There are many uses to this.

ISSUE TYPE

• Feature Idea

COMPONENT NAME

Core

[mkrizek]

#13262

[dagwieers]

@mkrizek Hmm, I searched for various combination of keywords, and that one did not stick out :-(

That said, I tried using until: with block:, include: and include_tasks, but the first one fails, and the 2 others only run the included file once.

- hosts: localhost
  tasks:
  - include: taskboot.yml
    until: 5|random == 5

But apparently looping only works when using loop: ?

- hosts: localhost
  tasks:
  - include: taskboot.yml
    loop: [ 1, 2, 3, 4, 5 ]

[dagwieers]

Whatever I try, using until: does not work with include: and include_tasks:.

- hosts: localhost
  tasks:
  - include: taskbook.yml
    until: false
    retries: 5
    delay: 1

[mkrizek]

Yeah, until is not a valid argument for includes, see #46177.

[dagwieers]

@mkrizek In other words, what we need is not possible, neither on blocks or on includes.

So I will keep this one open, but changed the title.

[sivel]

We do have an open proposal to "taskify" includes, which would allow things like until to work on them.

ansible/proposals#136

I, however, do not believe that blocks should be extended to support this feature.

[dagwieers]

@sivel And what would be the reason for not extending the functionality to blocks ? As it would be a natural thing if it would work. (i.e. being able to loop every construction within a play)

[bcoca]

blocks are currently 'static' groupings, enabling loops on them (not just having tasks inherit them) would require making them dynamic ... as we saw with include: this has many consequences that are not immediately apparent.

[sivel]

To extend what @bcoca mentions, doing so would require us to deprecate block and replace with something like block_dynamic and block_static.

Also, every user of ansible utilizes blocks, whether explicit, or our internal implicit use of them. They are a fundamental building block of how tasks are represented and executed. Changing such an integral feature is sure to lead to unforeseen issues.