JMESPath filter/MultiSelect on a large JSON file

If your goal is to have a set of data looking like this:

[
  {
    "destination":  "2001:db8:1::/48",
    "path": "64511 65551 I"
  },
  {
    "destination": "2001:db8:2::/48",
    "path": "65536 64496 I"
  }
]

It can simply be achieved with this query:

route-information[].route-table[].rt[].{destination: rt-destination[0].data, path: rt-entry[0].as-path[0].data}

But I suspect, with the lists you have under rt-destination, rt-entry and as-path, that this query might actually make you miss some data.

Here is one that is less likely going to make you miss data but that is creating a list under path, so the resulting JSON looks like:

[
  {
    "destination": [
      "2001:db8:1::/48"
    ],
    "path": [
      "64511 65551 I"
    ]
  },
  {
    "destination": [
      "2001:db8:2::/48"
    ],
    "path": [
      "65536 64496 I"
    ]
  }
]

And the query is:

route-information[].route-table[].rt[].{destination: rt-destination[*].data, path: rt-entry[*].as-path[*].data | [] }

This query makes use of the flatten operator |, which is explained in the examples under working with nested data.

Here is a script demonstrating this:

import jmespath

data = {
  "route-information": [
    {
      "route-table": [
        {
          "rt": [
            {
              "rt-destination": [
                {
                  "data": "2001:db8:1::/48"
                }
              ],
              "rt-entry": [
                {
                  "as-path": [
                    {
                      "data": "64511 65551 I"
                    }
                  ]
                }
              ]
            },
            {
              "rt-destination": [
                {
                  "data": "2001:db8:2::/48"
                }
              ],
              "rt-entry": [
                {
                  "as-path": [
                    {
                      "data": "65536 64496 I"
                    }
                  ]
                }
              ]
            }
          ]
        }
      ]
    }
  ]
}

query = [
    '"route-information"[]."route-table"[].rt[].{destination: "rt-destination"[0].data, path: "rt-entry"[0]."as-path"[0].data}',
    '"route-information"[]."route-table"[].rt[].{destination: "rt-destination"[*].data, path: "rt-entry"[*]."as-path"[*].data | [] }'
]

print(jmespath.search(query[0], data))
print('---------------------------')
print(jmespath.search(query[1], data))

Prints (prettified by hand):

[
   {
      "destination":"2001:db8:1::/48",
      "path":"64511 65551 I"
   },
   {
      "destination":"2001:db8:2::/48",
      "path":"65536 64496 I"
   }
]
---------------------------
[
   {
      "destination":[
         "2001:db8:1::/48"
      ],
      "path":[
         "64511 65551 I"
      ]
   },
   {
      "destination":[
         "2001:db8:2::/48"
      ],
      "path":[
         "65536 64496 I"
      ]
   }
]