json - jq - 将额外的 JSON 对象提取到新数组中

Question

我有一些 JSON。它看起来像这样:

{
"Volumes": [
    {
        "Attachments": [
            {
                "VolumeId": "vol-11111111",
                "State": "attached",
                "DeleteOnTermination": false,
                "Device": "/dev/sdz"
            }
        ],
        "Tags": [
            {
                "Value": "volume1",
                "Key": "Name"
            },
            {
                "Value": "00:00",
                "Key": "Start"
            },
            {
                "Value": "00:20",
                "Key": "Finish"
            },
            {
                "Value": "2",
                "Key": "Period"
            }
        ],
        "VolumeId": "vol-11111111"
    },
    {
        "Attachments": [
            {
                "VolumeId": "vol-22222222",
                "State": "attached",
                "DeleteOnTermination": false,
                "Device": "/dev/sdz"
            }
        ],
        "Tags": [
            {
                "Value": "volume2",
                "Key": "Name"
            },
            {
                "Value": "00:00",
                "Key": "Start"
            },
            {
                "Value": "00:20",
                "Key": "Finish"
            },
            {
                "Value": "2",
                "Key": "Period"
            }
        ],
        "VolumeId": "vol-22222222"
    },
    {
        "Attachments": [
            {
                "VolumeId": "vol-333333333",
                "State": "attached",
                "DeleteOnTermination": false,
                "Device": "/dev/sdz"
            }
        ],
        "Tags": [
            {
                "Value": "volume3",
                "Key": "Name"
            },
            {
                "Value": "00:00",
                "Key": "Start"
            },
            {
                "Value": "00:20",
                "Key": "Finish"
            },
            {
                "Value": "2",
                "Key": "Period"
            }
        ],
        "VolumeId": "vol-33333333"
    }
]
}

使用 jq，我能够提取以下信息:

VolumeId,Finish,Start,Period

使用 jq 命令

cat json | jq -r '[.Volumes[]|({VolumeId}+(.Tags|from_entries))|{VolumeId,Finish,Start,Period}]'

[
  {
    "VolumeId": "vol-11111111",
    "Finish": "00:20",
    "Start": "00:00",
    "Period": "2"
  },
  {
    "VolumeId": "vol-22222222",
    "Finish": "00:20",
    "Start": "00:00",
    "Period": "2"
  },
  {
    "VolumeId": "vol-33333333",
    "Finish": "00:20",
    "Start": "00:00",
    "Period": "2"
  }
]

---

一切正常。但是我需要额外提取.Attachments.Device。我正在寻找类似于以下内容的每个数组的输出:

 [
  {
    "VolumeId": "vol-11111111",
    "Finish": "00:20",
    "Start": "00:00",
    "Period": "2",
    "DeviceId": "/dev/sdz"
  },
  {
    "VolumeId": "vol-22222222",
    "Finish": "00:20",
    "Start": "00:00",
    "Period": "2",
    "DeviceId": "/dev/sdz"
  },
  {
    "VolumeId": "vol-33333333",
    "Finish": "00:20",
    "Start": "00:00",
    "Period": "2",
    "DeviceId": "/dev/sdz"
  }
]

但是我无法弄清楚如何在不出错的情况下执行此操作。对我来说最合乎逻辑的方法是做类似的事情:

cat json | jq -r '[.Volumes[]|({VolumeId}+(.Attachments|from_entries)+(.Tags|from_entries))|{VolumeId,Finish,Start,Period,DeviceId}]'

但是我得到了错误:

jq: error (at <stdin>:91): Cannot use null (null) as object key

任何帮助找出我做错了什么以及如何解决它的帮助将不胜感激。

谢谢

Answer 1

最终，问题是您在 Attachments 数组上使用 from_entries 而它不起作用。 from_entries 采用一组键/值对对象来创建具有这些值的对象。但是，您没有键/值对，而是对象。如果您只是想组合它们，您应该使用 add。

此外，没有名为 DeviceId 的属性，它是 Device。如果要选择 Device 属性并将其获取为 DeviceId，则需要提供正确的名称。

.Volumes | map(
    ({ VolumeId } + (.Attachments | add) + (.Tags | from_entries))
      | { VolumeId, Finish, Start, Period, DeviceId: .Device }
)