ansible json-query 路径以按内容选择项目 [英] ansible json-query path to select item by content

问题描述

有谁知道在下面的示例 JSON 中可以使用什么 json-query 过滤器来选择跳跳虎的食物?JSON 是大型且相对复杂的 AWS blob 的简化替代品.

Does anyone know what json-query filter can be used to select Tigger's food in the sample JSON below? The JSON is a simplified stand-in for a massive and relatively complicated AWS blob.

一些背景:我很高兴地发现 Ansible 有一个 json-query 过滤器.鉴于我试图从 AWS JSON blob 中选择一个元素，这看起来好像正是我所需要的.但是我很快就遇到了麻烦，因为 AWS 对象有标签，我需要按标签选择项目.

Some background: I was rather pleased to discover that Ansible has a json-query filter. Given that I was trying to select an element from an AWS JSON blob this looked as if it was just what I needed. However I quickly ran into trouble because the AWS objects have tags and I needed to select items by tag.

我尝试了相当于 Foods[Tags[(Key='For') & 的选择器路径](Value='Tigger')]] 和类似的，但没有设法让它工作.使用独立的 json-query 库，例如 https://www.npmjs.com/package/json-query 我可以使用 parent 属性，但这似乎不在 Ansible 中，除了偏离 json-query 的核心思想之外.

I tried selector paths equivalent to Foods[Tags[(Key='For') & (Value='Tigger')]] and similar but didn't manage to get it to work. Using a standalone json-query library such as https://www.npmjs.com/package/json-query I can use the parent attribute but that does not appear to be in Ansible, quite apart from being a deviation from the core idea of json-query.

最好避开这个问题并使用 jsonpath 选择器.jsonpath 类似于 json-query，是 xpath 的翻译.

It might be better to sidestep the problem and use a jsonpath selector. jsonpath is similar to json-query and is a translation from xpath.

{ "Foods" :
  [ { "Id": 456
    , "Tags":
      [ {"Key":"For", "Value":"Heffalump"}
      , {"Key":"Purpose", "Value":"Food"}
      ]
    }
  , { "Id": 678
    , "Tags":
      [ {"Key":"For", "Value":"Tigger"}
      , {"Key":"Purpose", "Value":"Food"}
      ]
    }
  , { "Id": 911
    , "Tags":
      [ {"Key":"For", "Value":"Roo"}
      , {"Key":"Purpose", "Value":"Food"}
      ]
    }
  ]
}

参考资料

• ansible 中的 json_query:http://docs.ansible.com/ansible/playbooks_filters.html#json查询过滤器
• json-query 独立节点:https://www.npmjs.com/package/json-查询
• jmespath，ansible 使用的库:http://jmespath.org/
• json-query 独立 python:https://pypi.python.org/pypi/jsonquery/(红鲱鱼)

推荐答案

您需要 id 列表吗?如果是这样，请尝试:

Do you need list of ids? If so, try:

- debug: msg="{{ lookup('file','test.json') | from_json | json_query(query) }}"
  vars:
    query: "Foods[].{id: Id, for: (Tags[?Key=='For'].Value)[0]} | [?for=='Tigger'].id"

首先构造具有必要字段的简单对象，然后通过管道将其传递给过滤器.

First construct simple objects with necessary fields and then pipe it to a filter.

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