当ansible中的变量未定义时，如何运行任务?

问题描述

我正在寻找一种方法来在ansible变量未注册/未定义的情况下执行任务

I am looking for a way to perform a task when ansible variable is not registers /undefined e.g

-- name: some task
   command:  sed -n '5p' "{{app.dirs.includes}}/BUILD.info" | awk '{print  $2}'
   when: (! deployed_revision) AND ( !deployed_revision.stdout )
   register: deployed_revision

推荐答案

来自可访问的文档:如果尚未设置必需变量，则可以使用Jinja2定义的测试跳过或失败.例如:

From the ansible docs:If a required variable has not been set, you can skip or fail using Jinja2’s defined test. For example:

tasks:

- shell: echo "I've got '{{ foo }}' and am not afraid to use it!"
  when: foo is defined

- fail: msg="Bailing out. this play requires 'bar'"
  when: bar is not defined

因此，在您的情况下，when: deployed_revision is not defined应该可以工作

So in your case, when: deployed_revision is not defined should work

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