如何使用Ansible/jq/json递归地搜索包含感兴趣元素的列表字典？

Question

我有一个Ansible剧本(版本2.9)，它最初使用lsblk命令显示可用的块设备。剧本是

- hosts: localhost
  tasks:
  - name: define variable
    shell: lsblk -oMOUNTPOINT,NAME  --json
    register: lsblk_output
  - debug:
      msg: "{{ lsblk_output.stdout }}"

lsblk命令的输出为JSON格式，lsblk -oMOUNTPOINT，NAME -json是

ok: [localhost] => {
    "msg": {
        "blockdevices": [
            {
                "mountpoint": "/snap/core18/2246",
                "name": "loop0"
            },
            {
                "mountpoint": "/snap/core18/2253",
                "name": "loop1"
            },
            {
                "mountpoint": "/snap/core20/1169",
                "name": "loop2"
            },
            {
                "mountpoint": "/snap/lxd/21803",
                "name": "loop3"
            },
            {
                "mountpoint": "/snap/core20/1242",
                "name": "loop4"
            },
            {
                "mountpoint": "/snap/lxd/21835",
                "name": "loop5"
            },
            {
                "mountpoint": "/snap/snapd/14066",
                "name": "loop6"
            },
            {
                "mountpoint": "/snap/snapd/13640",
                "name": "loop7"
            },
            {
                "children": [
                    {
                        "mountpoint": "/boot/efi",
                        "name": "sda1"
                    },
                    {
                        "mountpoint": "/boot",
                        "name": "sda2"
                    },
                    {
                        "children": [
                            {
                                "children": [
                                    {
                                        "mountpoint": "/",
                                        "name": "ubuntu--vg-ubuntu--lv"
                                    },
                                    {
                                        "mountpoint": null,
                                        "name": "ubuntu--vg-clean"
                                    }
                                ],
                                "mountpoint": null,
                                "name": "ubuntu--vg-ubuntu--lv-real"
                            },
                            {
                                "children": [
                                    {
                                        "mountpoint": null,
                                        "name": "ubuntu--vg-clean"
                                    }
                                ],
                                "mountpoint": null,
                                "name": "ubuntu--vg-clean-cow"
                            }
                        ],
                        "mountpoint": null,
                        "name": "sda3"
                    }
                ],
                "mountpoint": null,
                "name": "sda"
            },
            {
                "children": [
                    {
                        "mountpoint": null,
                        "name": "datavg-datavol1"
                    }
                ],
                "mountpoint": null,
                "name": "sdb"
            }
        ]
    }
}

如果我将上面的shell命令修改为lsblk -oMOUNTPOINT，名称为-json区jq‘.json\jq '.blockdevices[]区选择(.mountpoint == null) \ .name’

输出是

TASK [debug] *************************************************************************************************************************************************************
ok: [localhost] => {
    "msg": "\"sda\"\n\"sdb\""
}

但是，基于驱动器包含“挂载点”："/“这一事实，我只需要一个驱动器名。预期输出为sda。否则，我如何修改上述shell命令，以便执行递归搜索并获得所需的输出？

UPDATE我一直在扮演这个角色，

  - name: task22
    debug:
      msg: "{{ jsonym.blockdevices }}"
  - debug:
      msg: "{{ ((jsonym.blockdevices) | flatten) | json_query(query) | list }} "

    vars:
            query: "[].children.{na:jsonym.name, mp: [?mountpoint == '/boot'].name }"

输出是任务调试****************************************************************************************。

ok: [localhost] =>
  msg:
  - mp:
    - sda2
    na: null
  - mp: []
    na: null

仍然无法获得预期的产出。

Answer 1

注册变量lsblk_output.stdout是包含JSON数据的字符串。您必须通过from_yaml (或from_json，任何您喜欢的)从字符串中阅读字典。然后接受属性块设备并选择挂载点。例如，给定数据

  lsblk_output:
    stdout:
      blockdevices:
      - children:
        - mountpoint: /
          name: nvme0n1p6
        - mountpoint: /export
          name: nvme0n1p7
        mountpoint: null
        name: nvme0n1
      - children:
        - mountpoint: /root2
          name: nvme0n2p6
        - mountpoint: /export2
          name: nvme0n2p7
        mountpoint: null
        name: nvme0n2

下面的查询给出了'/‘挂载点的名称

  - debug:
      msg: "{{ (lsblk_output.stdout|from_yaml).blockdevices|
               json_query(query)|
               flatten }}"
    vars:
      query: "[].*[?mountpoint == '/'].name"

  msg:
  - nvme0n1p6

Answer 2

如果您使用gather_facts，您可以利用ansible_mounts事实而不是运行lsblk。

下面这样的任务可以过滤出安装在/上的磁盘/分区。

    - name: show root disk
      debug:
        msg: "{{ ansible_mounts | json_query(query) | first }}"
      vars:
        query: "[?mount == '/'].device"

结果如下：

ok: [localhost] => {
    "msg": "/dev/sda1"
}