linux - 如果不满足某些条件，如何跳过 ansible 剧本中的所有其他剧本？

Question

我在下面的剧本中有多个剧本。如果不满足某些条件，我想忽略所有其他播放。

所以对于下面的示例 - 如果我在 Play1 中找不到任何新文件，那么我不想执行 Play2 和 Play3全部(它应该跳过它)。我该怎么做？

我在 Play1 中有 end_play 但它只跳过 Play1 并且它仍然执行 Play2 和 Play3

---
- name: Play 1
  hosts: 127.0.0.1
  tasks:
      - name: find the latest file
        find: paths=/var/lib/jenkins/jobs/process/workspace/files
              file_type=file
              age=-1m
              age_stamp=mtime
        register: files

      - meta: end_play
        when: files.files|count == 0

      - name: Copy file, if found
        copy:
          src: "some stuff here"
          dest: "some other stuff here"
        when: files.files|count > 0

- name: Play 2
  hosts: all
  serial: 5
  tasks:
      - name: copy latest file
        copy: src=data_init/goldy.init.qa dest=/data01/admin/files/goldy.init.qa owner=golden group=golden

      - name: copy latest file
        copy: src=data_init/goldy.init.qa dest=/data02/admin/files/goldy.init.qa owner=golden group=golden

- name: Play 3
  hosts: 127.0.0.1
  tasks:
      - name: execute command
        shell: ./data_init --init_file ./goldy.init.qa
        args:
          chdir: /var/lib/jenkins/jobs/process/workspace/data_init/

更新:

所以 block 模块解决方案看起来不起作用，因为你不能像那样在 block 中使用嵌套播放..

Answer 1

有两种方法可以解决您的问题:

1. 虽然您尝试定义一个hosts: localhost 来在 Controller 上运行一些任务是可以理解的，但您实际上并不需要这个。使用 delegate_to: localhost和 run_once: true在你想在你的 Controller 上运行的步骤是一个更好的方法。
2. 如果你真的想这样做(使用hosts: localhost)，出于某种原因，那么你需要保存你的find的返回值， set_fact为了在全局 hostvars 的帮助下在其他主机中重用它

---

使用委托(delegate)

剧中的任何任务都可以委托(delegate)给另一位主持人。这非常简单，只需在您的任务中使用一个额外的 delegate_to 选项即可:

- name: Delegate a find to localhost
  find: 
    path: /test
    file_type: any
  register: localhost_find
  delegate_to: localhost
  run_once: true

这样做时，我建议您也使用 run_once: true，因为如果您将任务委托(delegate)给另一台主机，则没有必要，假设您运行十次您的主机组中有十台主机。

举个例子

---
- hosts: hosts
  become: true
  gather_facts: false

  tasks:
    - name: Delegate directory creation to localhost
      file: 
        path: /test
        state: directory
      delegate_to: localhost
      run_once: true

    - name: Create directory on hosts
      file:
        path: /test                 
        state: directory

    - name: Delegate file creation to localhost
      file:
        path: /test/localhost.txt                 
        state: touch
      delegate_to: localhost
      run_once: true

    - name: Create file on hosts
      file:
        path: /test/host.txt
        state: touch

    - name: Delegate a find to localhost
      find: 
        path: /test
        file_type: any
      register: localhost_find
      delegate_to: localhost
      run_once: true

    - name: Find in the hosts for comparison
      find:
        path: /test
        file_type: any
      register: host_find

    - name: List /test of localhost
      debug:
        msg: "{{ localhost_find.files | map(attribute='path') | list }}"

    - name: List /test of host
      debug:    
        msg: "{{ host_find.files | map(attribute='path') | list }}"      

    - name: Remove /test folder on localhost
      file:
        path: /test
        state: absent
      delegate_to: localhost
      run_once: true

    - name: Delegate an empty find to localhost
      find:
        path: /test
        file_type: any
      register: empty_find
      delegate_to: localhost
      run_once: true

    - name: Here are our hostnames from the inventory
      debug:
        msg: "{{ inventory_hostname }}"

    - name: I am the evil host killer
      meta: end_host
      when: empty_find.files | count == 0 and inventory_hostname != 'host1' 

    - debug:
        msg: "I am a sad message, because I will never display :'( But hopefully host1 likes me :')"

    - name: I am the evil playbook killer
      meta: end_play
      when: empty_find.files | count == 0

    - debug:
        msg: "I am a sad message, because I will never display :'( No one likes me..."

在您可以看到的地方，我通过结束播放跳过了最后一条调试消息，当时我在之前的步骤中结束了主机组中的三台主机中的两台。

该剧本的输出:

PLAY [hosts] **************************************************************************************************************************

TASK [Delegate directory creation to localhost] ***************************************************************************************
ok: [host1 -> localhost]

TASK [Create directory on hosts] ****************************************************************************************************
ok: [host3]
ok: [host2]
ok: [host1]

TASK [Delegate file creation to localhost] ********************************************************************************************
changed: [host1 -> localhost]

TASK [Create file on hosts] ****************************************************************************************************
changed: [host2]
changed: [host1]
changed: [host3]

TASK [Delegate a find to localhost] ***************************************************************************************************
ok: [host1 -> localhost]

TASK [Find in the host for comparison] ************************************************************************************************
ok: [host1]
ok: [host3]
ok: [host2]

TASK [List /test of localhost] ********************************************************************************************************
ok: [host1] => {
    "msg": [
        "/test/localhost.txt"
    ]
}
ok: [host2] => {
    "msg": [
        "/test/localhost.txt"
    ]
}
ok: [host3] => {
    "msg": [
        "/test/localhost.txt"
    ]
}

TASK [List /test of host] *************************************************************************************************************
ok: [host1] => {
    "msg": [
        "/test/host.txt"
    ]
}
ok: [host2] => {
    "msg": [
        "/test/host.txt"
    ]
}
ok: [host3] => {
    "msg": [
        "/test/host.txt"
    ]
}

TASK [Remove /test folder on localhost] ***********************************************************************************************
changed: [host1 -> localhost]

TASK [Delegate an empty find to localhost] ********************************************************************************************
ok: [host1 -> localhost]

TASK [Here are our hostnames from the inventory] **************************************************************************************
ok: [host1] => {
    "msg": "host1"
}
ok: [host2] => {
    "msg": "host2"
}
ok: [host3] => {
    "msg": "host3"
}

TASK [debug] **************************************************************************************************************************
ok: [host1] => {
    "msg": "I am a sad message, because I will never display :'( But hopefully host1 likes me :')"
}

PLAY RECAP ****************************************************************************************************************************
host1                      : ok=12   changed=3    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
host2                      : ok=6    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
host3                      : ok=6    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0  

在输出中，你可以很容易地发现委派，就像输出一样

changed: [host1 -> localhost]

当一个非委派的任务刚刚开始时

changed: [host1]

---

使用主机变量

我想说这种方法有点不那么先进，但如果您想委托(delegate)边缘情况，它会变得很方便。我以前用过它，所以它并不是没有不能结束的情况是正确的解决方案。

这是例子

---
- hosts: localhost
  gather_facts: false

  tasks:
    - name: Find in localhost
      find:
        path: /not/existing/folder
        file_type: any
      register: find

    - name: This will register the list under find.files as a variable on the host, making it accessible via hostvars
      set_fact:
        find_result: "{{ find.files }}"

    - meta: end_play
      when: find.files | count == 0

    - debug:
        msg: I am the sanity check message, proving the end_play did happen


- hosts: hosts
  gather_facts: false

  tasks:
    - name: Just to show we are not cheating with an empty host group, we display the hosts names
      debug:
        msg: "{{ inventory_hostname }}"

    - name: To show it is really our empty list and not an empty string or a null variable
      debug:
        msg: "{{ hostvars['localhost']['find_result'] }}"

    - meta: end_play
      when: "hostvars['localhost']['find_result'] | count == 0"

    - debug:
        msg: I am a first sanity check message, proving the end_play did happen

    - debug:
        msg: I am a second sanity check message, proving the end_play did happen


- hosts: localhost
  gather_facts: false

  tasks:
    - name: To show it is really our empty list and not an empty string or a null variable
      debug:
        msg: "{{ hostvars['localhost']['find_result'] }}"

    - meta: end_play
      when: "hostvars['localhost']['find_result'] | count == 0"

    - debug:
        msg: I am a first sanity check message, proving the end_play did happen

    - debug:
        msg: I am a second sanity check message, proving the end_play did happen

你可以看到，在主机的每个新任务组开始时，我只是根据变量 find_result 运行 meta 来结束播放注册出来的find结果

这是这个的输出

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

TASK [Find in localhost] **************************************************************************************************************
ok: [localhost]

TASK [This will register the list under find.files as a variable on the host, making it accessible via hostvars] *********************
ok: [localhost]

PLAY [hosts] **************************************************************************************************************************

TASK [Just to show we are not cheating with an empty host group, we display the hosts names] ******************************************
ok: [host1] => {
    "msg": "host1"
}
ok: [host2] => {
    "msg": "host2"
}
ok: [host3] => {
    "msg": "host3"
}

TASK [To show it is really our empty list and not an empty string or a null variable] ************************************************
ok: [host1] => {
    "msg": []
}
ok: [host2] => {
    "msg": []
}
ok: [host3] => {
    "msg": []
}

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

TASK [To show it is really our empty list and not an empty string or a null variable] ************************************************
ok: [localhost] => {
    "msg": []
}

PLAY RECAP ****************************************************************************************************************************
host1                      : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
host2                      : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
host3                      : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
localhost                  : ok=3    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0