当变量具有默认值时，Ansible playbook 条件失败 [英] Ansible playbook condition fails when variable has a default value

问题描述

给定以下剧本(deployment.yml):

---
- name: Debug
  hosts: applicationservers
  tasks:
  - debug: msg="{{add_host_entries | default('false')}}"
  - debug: msg="{{add_host_entries | default('false') == 'true'}}"
  - debug: msg="Add host entries = {{add_host_entries | default('false') == 'true'}}"

- include: add_host_entries.yml
  when: add_host_entries | default('false') == 'true'

包含 add_host_entries.yml 的条件总是失败，即使上述所有调试消息都打印了某种 true(我知道在第一条调试消息中它是一个字符串，而其他两个结果是布尔值).

The condition to include add_host_entries.yml always fails, even if all of the above debug messages print some sort of true (I know that in the first debug message it's a String, whereas the other two result in Booleans).

当我省略有默认值的部分时，会执行add_host_entries.yml:

When I omit the part with the default value, add_host_entries.yml will be executed:

  when: add_host_entries

不过我需要这个默认值行为，因为它是一个仅在某些阶段设置的可选值.

I need this default value behaviour though, because it's an optional value which is only set on certain stages.

  when: (add_host_entries | default('false')) == 'true'

转换为布尔值

  when: add_host_entries|default('false')|bool

其他来源和信息

这里是重现问题所需的所有资源.

Other Sources and Information

Here are all the resources needed to reproduce the problem.

---
- name: add_host_entries
  hosts: applicationservers
  gather_facts: false
  tasks:
    - debug: msg="Add Host Entries"

库存

[applicationservers]
127.0.0.1

[all:vars]
add_host_entries=true

打电话

markus@lubuntu:~/foobar$ ansible-playbook deployment.yml -i inventory

版本

markus@lubuntu:~/foobar$ ansible --version
ansible 2.1.1.0
  config file = /etc/ansible/ansible.cfg
  configured module search path = Default w/o overrides

markus@lubuntu:~/foobar$ ansible-playbook --version
ansible-playbook 2.1.1.0
  config file = /etc/ansible/ansible.cfg
  configured module search path = Default w/o overrides

推荐答案

您尝试有条件地包含 剧本.请参阅我关于不同包含类型的其他答案.

You try to conditionally include playbook. See my other answer about different include types.

问题是，这仅在之前定义变量时有效.Ansible 解析您的剧本.
但是您尝试将 add_host_entries 定义为主机级事实(组变量)——这些变量在解析时尚未定义.

The thing is, this only works when variable is defined before Ansible parses your playbook.
But you try to define add_host_entries as host-level fact (group variable) – these variables are not yet defined during parse time.

如果您使用 -e add_host_entries=true 调用您的剧本，您的条件将按预期工作，因为额外变量在解析时是已知的.

If you call your playbook with -e add_host_entries=true your condition will work as expected, because extra-vars are known during parse time.

这篇关于当变量具有默认值时，Ansible playbook 条件失败的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！