如果自定义变量设置为 true，则执行任务

Question

当且仅当自定义变量（来自 main，playbook.yml）设置为 true 时，我愿意执行任务。我已经尝试了几次，但 none 成功了。

这是我最近的尝试：

在tasks/main.yml中：

- name: Unpack Nexus main configurations
  unarchive:
    src="{{ nexus_configs_download_dir }}/{{ nexus_main_configurations }}"
    dest="{{ nexus_installation_dir }}"
    creates="{{ nexus_installation_dir }}/nexus-professional-{{ nexus_version }}"
    force=no
    copy=false
    owner={{ nexus_os_user }}
    group={{ nexus_os_group }}
    mode="0755"
  when: "{{ nexus_main_select_configuration | True }}"
  tags: 
    - unpack
    - ansible-nexus

- name: Unpack Nexus sync configurations
  unarchive:
    src="{{ nexus_configs_download_dir }}/{{ nexus_sync_configurations }}"
    dest="{{ nexus_installation_dir }}"
    creates="{{ nexus_installation_dir }}/nexus-professional-{{ nexus_version }}"
    force=no
    copy=false
    owner={{ nexus_os_user }}
    group={{ nexus_os_group }}
    mode="0755"
  when: "{{ nexus_sync_select_configuration | True }}"
  tags: 
    - unpack
    - ansible-nexus

- name: Unpack Nexus proxy configurations
  unarchive:
    src="{{ nexus_configs_download_dir }}/{{ nexus_proxy_configurations }}"
    dest="{{ nexus_installation_dir }}"
    creates="{{ nexus_installation_dir }}/nexus-professional-{{ nexus_version }}"
    force=no
    copy=false
    owner={{ nexus_os_user }}
    group={{ nexus_os_group }}
    mode="0755"
  when: "{{ nexus_proxy_select_configuration | True }}"
  tags: 
    - unpack
    - ansible-nexus

在defaults/main.yml中：

---
# [REDACTED]
nexus_installation_dir: '/usr/share'
nexus_main: false
nexus_sync: false
nexus_proxy: false
nexus_main_select_configuration: "{{ nexus_main | bool }}"
nexus_sync_select_configuration: "{{ nexus_sync | bool }}"
nexus_proxy_select_configuration: "{{ nexus_proxy | bool }}"

主要playbook.yml:

---

- hosts: 127.0.0.1
  connection: local
  roles:
  - { role: covs.nexus,
      nexus_version: '2.14.1-01',
      nexus_installation_dir: '/opt',
      nexus_port: 8080,
      nexus_webapp_context_path: '/',
      nexus_proxy: true,
      become: yes}

最近一次尝试时出现以下错误：

TASK [covs.nexus : Unpack Nexus main configurations] ***************************
fatal: [127.0.0.1]: FAILED! => {"failed": true, "msg": "The conditional check '{{ nexus_main_select_configuration | True }}' failed. The error was: template error while templating string: no filter named 'True'. String: {{ nexus_main_select_configuration | True }}\n\nThe error appears to have been in '/home/ubuntu/covs-nexus-ansible/tasks/main.yml': line 276, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n- name: Unpack Nexus main configurations\n  ^ here\n"}

我试图从 this page 那里获得帮助，但他们的示例基于运行机器上的命令，然后根据该命令执行某些操作。我在剧本中找不到基于另一个 yml 文件中的变量的条件示例。

Answer 1

那里的第一个例子使用变量 ansible_os_family:

  - name: "shut down Debian flavored systems"
    command: /sbin/shutdown -t now
    when: ansible_os_family == "Debian"

注意这句话：

This is easy to do in Ansible with the when clause, which contains a raw Jinja2 expression without double curly braces.

所以您只需要删除它们（以及那些奇怪的 | True 过滤器）。

when: nexus_sync_select_configuration

Answer 2

好吧，因为我仍然对我做事的方式有疑问（查看的评论），我最终改变了我做事的方式，而不是最漂亮的，解决方案.. 这就是我所做的（我相信有更好的方法来做到这一点）：

我已经删除了 defaults/main.yml 中与此问题相关的所有内容，并将与此相关的任务移至实际的 playbook yaml 文件中。

这意味着现在我有 3 个主要的剧本 yaml 文件可供选择。

这是其中之一（其他类似）：

nexus-sync.yml:

---

- hosts: 127.0.0.1
  connection: local
  roles:
  - { role: covs.nexus,
      nexus_version: '2.14.1-01',
      nexus_installation_dir: '/opt',
      nexus_port: 8080,
      nexus_webapp_context_path: '/',
      become: yes}
  tasks:
    - name: Remove all contents of configuration dir
      become: yes
      shell: rm -rf {{ nexus_working_dir }}/conf
      tags:
        - ansible-nexus
    - name: Unpack Nexus sync configurations
      become: yes
      unarchive:
        src="{{ nexus_sync_configurations }}"
        dest="{{ nexus_working_dir }}"
        creates="{{ nexus_working_dir }}/conf"
        force=no
        copy=false
        owner={{ nexus_os_user }}
        group={{ nexus_os_group }}
        mode="0755"
        recursive: true
      notify:
        - 'restart nexus'
      tags: 
        - unpack
        - ansible-nexus

如果有人发布了另一个比这个更好的有效答案，我会选择它作为已解决的答案，因为这个有效但不是最好的解决方案。

如果自定义变量设置为 true，则执行任务

Do task if custom variable is set to true

ansible

yaml

ansible-playbook