计算两个变量之间的天数（一个是设定变量，另一个来自事实）

Question

我一直在疯狂地寻找解决方案，但到目前为止我一直没有成功：计算库存变量和 Ansible 事实之间的天数。

当我手动设置两个变量时我没有问题，两者都被识别为日期，我可以从那里开始工作：（这是预期的输出）

在 2 个手动设置的变量之间工作的任务：

---
- hosts: localhost

  vars:
    prev_date: 2020-12-01
    cur_date: 2020-12-31

  tasks:
    - name: prev_date debug
      debug:
        msg:
          - "prev_date: {{ prev_date }}"
          - "prev_date type: {{ prev_date | type_debug }}"

    - name: cur_date debug
      debug:
        msg:
          - "cur_date: {{ cur_date }}"
          - "cur_date type: {{ cur_date | type_debug }}"

    # This is the output I want to get but I want cur_date from a dynamic source (fact or shell through register)
    - name: Calculate number of days between prev_date and cur_date (intended result)
      debug:
        msg: "Number of days = {{ (cur_date - prev_date).days }}"

工作输出：

TASK [prev_date debug] *************************************************************************************************************************************************
Thursday 31 December 2020  12:55:28 +0100 (0:00:00.227)       0:00:00.227 *****
ok: [localhost] => {
    "msg": [
        "prev_date: 2020-12-01",
        "prev_date type: date"
    ]
}

TASK [cur_date debug] **************************************************************************************************************************************************
Thursday 31 December 2020  12:55:29 +0100 (0:00:00.249)       0:00:00.476 *****
ok: [localhost] => {
    "msg": [
        "cur_date: 2020-12-31",
        "cur_date type: date"
    ]
}

TASK [Calculate number of days between prev_date and cur_date (intended result)] ***************************************************************************************
Thursday 31 December 2020  12:55:29 +0100 (0:00:00.144)       0:00:00.621 *****
ok: [localhost] => {
    "msg": "Number of days = 30"
}

现在，由于变量类型，我想使用 ansible fact 在每次运行时动态获取当前日期 (ansible_date_time.date)

重现错误的任务示例

    - name: Value and type of ansible_date_time.date
      debug:
        msg:
          - "ansible_date_time.date: {{ ansible_date_time.date }}"
          - "ansible_date_time.date type: {{ ansible_date_time.date | type_debug }}"

    # Failing due to conditional not working with attribute not being date on ansible_date_time.date
    - name: Calculate number of days between ansible_date_time.date
      debug:
        msg:
          - "Number of days = {{ (ansible_date_time.date - prev_date).days }}"

我得到以下输出和错误：

TASK [New source ansible fact date] ************************************************************************************************************************************
Thursday 31 December 2020  13:06:41 +0100 (0:00:00.143)       0:00:00.741 *****
ok: [localhost] => {
    "msg": [
        "ansible_date_time.date: 2020-12-31",
        "ansible_date_time.date type: AnsibleUnsafeText"
    ]
}

TASK [Calculate number of days between ansible_date_time.date] *********************************************************************************************************
Thursday 31 December 2020  13:06:41 +0100 (0:00:00.150)       0:00:00.892 *****
fatal: [localhost]: FAILED! => {"msg": "Unexpected templating type error occurred on (Number of days = {{ (ansible_date_time.date - prev_date).days }}): unsupported operand type(s) for -: 'AnsibleUnsafeText' and 'datetime.date'"}

我尝试找到从 ansible_date_time.date 中创建新变量的方法，但如果可能的话，我无法将其转换为 datetime.date。

Answer 1

ansible_date_time.date 是一个字符串，因此您必须将其转换为 date 或 datetime。

令人惊讶的是，Ansible 无法立即将字符串转换为date，但您可以使用to_datetime filter 将其转换为datetime。

然后，由于prev_date 包含date 而不是datetime，因此您可以通过Python 的datetime 的date() 函数将刚刚创建的datetime 转换为date。

所以剧本是：

- hosts: all
      
  tasks:
    - debug:
        msg: "{{ ((ansible_date_time.date | to_datetime('%Y-%m-%d')).date() - prev_date).days }}"
      vars:
        prev_date: 2020-12-01

这会给：

PLAY [all] *******************************************************************************************************

TASK [Gathering Facts] *******************************************************************************************
ok: [localhost]

TASK [debug] *****************************************************************************************************
ok: [localhost] => {
    "msg": "30"
}

PLAY RECAP *******************************************************************************************************
localhost                  : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0 

Answer 2

下面的任务完成了这项工作

    - debug:
        msg: "Number of days =
              {{ ((ansible_date_time.date|to_datetime('%Y-%m-%d') -
                  (prev_date ~ ' 00:00:00')|to_datetime)).days }}"