如何从JSON输出在Ansible中构建指定结构的字典

问题场景 #

我有一个针对2个及以上URL执行的Ansible任务，每个URL返回的变量结构一致但具体值不同，任务的JSON注册表数据如下：

{
  "msg": {
    "results": [
      {
        "url": "http://0.0.0.1:xxx1",
        "othervar": "othervar",
        "othervar2": "othervar2",
        "json": {
          "messages": [
            {
              "message": "This is message number 1",
              "message2": "This is message2 number 1"
            },
            {
              "message": "This is message number 2",
              "message2": "This is message2 number 2"
            },
            {
              "message": "This is message number 3",
              "message2": "This is message2 number 3"
            }
          ]
        }
      },
      {
        "url": "http://0.0.0.2:xxx2",
        "othervar": "othervar",
        "othervar2": "othervar2",
        "json": {
          "messages": [
            {
              "message": "This is message number 1",
              "message2": "This is message2 number 1"
            },
            {
              "message": "This is message number 2",
              "message2": "This is message2 number 2"
            },
            {
              "message": "This is message number 3",
              "message2": "This is message2 number 3"
            }
          ]
        }
      }
    ]
  }
}

预期结果 #

需要提取url、message和message2变量，整合成以下两种结构之一：

选项1：按URL分组 #

{
  "message": [
    {
      "url": "http://0.0.0.1:xxx1",
      "content": [
        {
          "message": "This is message number 1",
          "message2": "This is message2 number 1"
        },
        {
          "message": "This is message number 2",
          "message2": "This is message2 number 2"
        },
        {
          "message": "This is message number 3",
          "message2": "This is message2 number 3"
        }
      ]
    },
    {
      "url": "http://0.0.0.2:xxx2",
      "content": [
        {
          "message": "This is message number 1",
          "message2": "This is message2 number 1"
        },
        {
          "message": "This is message number 2",
          "message2": "This is message2 number 2"
        },
        {
          "message": "This is message number 3",
          "message2": "This is message2 number 3"
        }
      ]
    }
  ]
}

选项2：展开所有消息条目 #

{
  "message": [
    {
      "url": "http://0.0.0.1:xxx1",
      "message": "This is message number 1",
      "message2": "This is message2 number 1"
    },
    {
      "url": "http://0.0.0.1:xxx1",
      "message": "This is message number 2",
      "message2": "This is message2 number 2"
    },
    {
      "url": "http://0.0.0.1:xxx1",
      "message": "This is message number 3",
      "message2": "This is message2 number 3"
    },
    {
      "url": "http://0.0.0.2:xxx2",
      "message": "This is message number 1",
      "message2": "This is message2 number 1"
    },
    {
      "url": "http://0.0.0.2:xxx2",
      "message": "This is message number 2",
      "message2": "This is message2 number 2"
    },
    {
      "url": "http://0.0.0.2:xxx2",
      "message": "This is message number 3",
      "message2": "This is message2 number 3"
    }
  ]
}

实现方案 #

生成选项1结构 #

使用set_fact结合Jinja2循环，遍历每个URL的结果，提取url并将json.messages作为content字段：

- name: 构建选项1的结构化数据
  set_fact:
    option1_result:
      message: >-
        {% set output = [] %}
        {% for res in msg.results %}
          {% set _ = output.append({'url': res.url, 'content': res.json.messages}) %}
        {% endfor %}
        {{ output }}

生成选项2结构 #

同样用set_fact嵌套循环，先遍历每个URL结果，再遍历该URL下的所有消息条目，将url与每个消息字典合并：

- name: 构建选项2的结构化数据
  set_fact:
    option2_result:
      message: >-
        {% set output = [] %}
        {% for res in msg.results %}
          {% for msg_item in res.json.messages %}
            {% set _ = output.append({'url': res.url} | combine(msg_item)) %}
          {% endfor %}
        {% endfor %}
        {{ output }}

执行完上述任务后，option1_result和option2_result变量就分别对应两种预期结构，可直接在后续任务中调用。

内容的提问来源于stack exchange，提问作者asking