JOLT 转换以沿数组复制单个值答案

【问题标题】：JOLT transformation to copy single value along an arrayJOLT 转换以沿数组复制单个值
【发布时间】：2018-05-18 14:10:41
【问题描述】：

我想将 JSON 转换为键值对，同时将特定的单个值（即“时间戳”）复制到所有这些对。

输入 JSON：

{
  "Timestamp": "2018-05-13T14:57:09",
  "first_key": "1023",
  "another_key": "1987",
  "yet_another_key": "677"
}

预期输出：

[ {
    "Timestamp": "2018-05-13T14:57:09.087",
    "key": "first_key",
    "value": "1023"
  },
  {
    "Timestamp": "2018-05-13T14:57:09.087",
    "key": "another_key",
    "value": "1987"
  },
  {
    "Timestamp": "2018-05-13T14:57:09.087",
    "key": "yet_another_key",
    "value": "677"
  }]

到目前为止，我想出的是以下 JOLT 规范。它已经为所有不是“时间戳”的条目生成了键值对，但是如何将“时间戳”的值复制到每个记录中？

[{
  "operation": "shift",
  "spec": {
    "Timestamp": "[].Timestamp",
    "*": {
      "$": "[#2].key",
      "@": "[#2].value"
    }
  }
}]

上述 JOLT 规范的输出：

[ {
  "Timestamp" : "2018-05-13T14:57:09"
}, {
  "key" : "first_key",
  "value" : "1023"
}, {
  "key" : "another_key",
  "value" : "1987"
}, {
  "key" : "yet_another_key",
  "value" : "677"
} ]

【问题讨论】：

标签： json jolt

【解决方案1】：

规格

[
  {
    // first separate the Timestamp from the fields that 
    //  are going to be pivoted.
    // This is needed because the "[#2]" logic 
    //  isn't doing what you think it is / 
    //  you would end up with a null in your output array.
    // Basically the "[#2]" logic as written only works
    //  when you are cleanly pivoting data.  Which you are
    //  not because "Timestamp" and "first_key" are siblings.
    "operation": "shift",
    "spec": {
      "Timestamp": "Timestamp",
      "*": "keysToPivot.&"
    }
  },
  {
    "operation": "shift",
    "spec": {
      "keysToPivot": {
        "*": {
          // Now that we can cleanly loop thru _only_ the 
          //  keysToPivot, the [#2] logic will work "right".
          // Additionally, lookup the Timestamp value
          //  and add it to each "pivoted" output.
          "$": "[#2].key",
          "@": "[#2].value",
          "@(2,Timestamp)": "[#2].Timestamp"
        }
      }
    }
  }
]

【讨论】：