JSON format output for http query interface

[sunng87]

What type of enhancement is this?

API improvement

What does the enhancement do?

Some BI or visualization tools like PowerBI accepts json data from custom web apis. So if we offer json based http API, it's possible to integration these type of tool without any modification from both side.

Before, we need to modify the database driver of these type of tools, like this and this, in order to make it work with GreptimeDB. But for close-source tools or hosted ones, there is no way to do that.

Our default json output is in a table based data mode, which is not very friendly for client to consume directly.

{
  "output": [
    {
      "records": {
        "schema": {
          "column_schemas": [
            {
              "name": "host",
              "data_type": "String"
            },
            {
              "name": "ts",
              "data_type": "TimestampMillisecond"
            },
            {
              "name": "cpu",
              "data_type": "Float64"
            },
            {
              "name": "memory",
              "data_type": "Float64"
            }
          ]
        },
        "rows": [
          [
            "127.0.0.1",
            1667446797450,
            0.1,
            0.4
          ],
          [
            "127.0.0.1",
            1667446798450,
            0.5,
            0.2
          ],
          [
            "127.0.0.2",
            1667446798450,
            0.2,
            0.3
          ]
        ],
        "total_rows": 3
      }
    }
  ],
  "execution_time_ms": 23
}

The idea it to create an alternative format, say format=json, and the data format should look like:

{
  "data": [
    {
      "host": "127.0.0.1",
      "ts": 1667446797450,
      "cpu": 0.2,
      "memory": 0.3
    },
    ...
  ],
  "execution_time_ms": 23
}

Implementation challenges

No response