Ansible：如何为角色实施条件？ （获取错误）

Question

我的比赛如下：

---
- hosts: influxdbmeta_lab, influxdbdata_lab
  gather_facts: true
  become: true
  tasks:
    - shell: "docker ps --format '{{.Image}}' | grep influx"
      register: command_result
    - name: setting fact 
      set_fact: string_to_echo = "{{ command_result.stdout }}"
  roles:
    - role: influxdb-upgrade
      when: (string_to_echo == "--meta")

运行此剧本时，出现以下错误：

TASK [influxdb-upgrade : Creating directories] ************************************************************************************************************
fatal: [influxmetalab-1]: FAILED! => {"msg": "The conditional check '(string_to_echo == \"--meta\")' failed. The error was: error while evaluating conditional ((string_to_echo == \"--meta\")): 'string_to_echo' is undefined\n\nThe error appears to be in '/Users/zafaab1/git-repos/deploy-vcp-performance/ansible_home/roles/influxdb-upgrade/tasks/main.yml': line 3, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n# Ensures that the directories are there. For upgrade, Ansible will simply mark this as OK\n- name: Creating directories\n  ^ here\n"}

我只是不确定为什么string_to_echo显示为未定义。 任何建议将不胜感激

我尝试了各种组合。我尝试将shell命令放置在该角色的实际任务中：influxdb-upgrade。但是，这会产生相同的错误。

Answer 1

在戏剧中，角色在任务执行之前执行。当执行 roles：语句时，尚未声明变量 string_to_echo 。

例如，让我们使用一个只有一个任务的简单角色

$ cat roles/role1/tasks/main.yml 
- debug:
    var: test_var

下面的戏

- hosts: localhost
  tasks:
    - set_fact:
        test_var: test
    - debug:
        var: test_var
  roles:
    - role1

给予

PLAY [localhost] ****************************************************************************

TASK [role1 : debug] ************************************************************************
ok: [localhost] => {
    "test_var": "VARIABLE IS NOT DEFINED!"
}

TASK [set_fact] *****************************************************************************
ok: [localhost]

TASK [debug] ********************************************************************************
ok: [localhost] => {
    "test_var": "test"
}

PLAY RECAP **********************************************************************************
localhost                  : ok=3    changed=0    unreachable=0    failed=0

使用include_role来更改工作流程以满足您的需求。

- hosts: localhost
  gather_facts: false
  tasks:
    - set_fact:
        test_var: test
    - debug:
        var: test_var
    - include_role:
        name: role1
      when: test_var == 'test'