Ansible:应用何时完成循环 [英] Ansible: apply when to complete loop

问题描述

我想将 ansible 中的循环与应用于它的 when 语句结合起来.然而，当语句应用于每个循环迭代时，这消除了将一个应用于完整循环的可能性.有人知道怎么做吗?

I want to combine a loop in ansible with a when-statement applied to it. When-statements are applied to each loop iteration however, which takes away the possibility to apply one to the complete loop. Does anyone know how to do this?

我以前遇到过这个问题，但在这种特定情况下，它涉及一个可能存在也可能不存在的变量.我想做的是:

I've run into this problem before, but in this specific case it concerns a variable that might or might not exist. What I would want to do is something like:

- name: Loop
  debug:
    msg: "{{ item }}"
  with_items: x.y|default([])
  but-only-run-this-loop-when: x is defined

默认过滤器处理那些未定义 y 的情况.由于在我的情况下 x 可能还没有定义，我需要但仅运行此循环时.显然，这不是一个真正的 ansible 声明.我应该用什么代替?

The default-filter takes care of those instances where y is not defined. Since in my case x might als be not defined, I need the but-only-run-this-loop-when. Obviously, this is not a real ansible statement. What should I use in stead?

目前，我使用一些可怕的东西:

Currently, I use something horrible like:

- name: kludge1
  set_fact:
    fake_y : "{{ [] }}"

- name: kludge2
  set_fact:
    fake_y : "{{ x.y|default([]) }}"
  when: x is defined

- name: Loop
  debug:
    msg: "{{ item }}"
  with_items: '{{ fake_y }}'

例如在 host_vars 中:

With for example in host_vars:

x:
  y:
    - "foo"
    - "bar"

但我敢肯定那不是要走的路.

But I'm sure that's not the way to go.

推荐答案

有类似的答案 此处.您可以连续使用多个默认值:

There's similar answer here. You can use several defaults in a row:

- name: Loop
  debug:
    msg: "{{ item }}"
  with_items: (x | default({})).y | default([])

并且没有办法将 when 语句绑定到整个循环任务(至少在当前的 Ansible 2.2 中).

And there is no way to bound when statement to looped task as a whole (at least in current Ansible 2.2).

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