Json Path usage

jsonpath.md

title
JSONPath Support

JSONPath template is composed of JSONPath expressions enclosed by {}. And we add three functions in addition to the original JSONPath syntax:

1. The $ operator is optional since the expression always starts from the root object by default.
2. We can use "" to quote text inside JSONPath expressions.
3. We can use range operator to iterate lists.

The result object is printed as its String() function.

Given the input:

{
  "kind": "List",
  "items":[
    {
      "kind":"None",
      "metadata":{"name":"127.0.0.1"},
      "status":{
        "capacity":{"cpu":"4"},
        "addresses":[{"type": "LegacyHostIP", "address":"127.0.0.1"}]
      }
    },
    {
      "kind":"None",
      "metadata":{"name":"127.0.0.2"},
      "status":{
        "capacity":{"cpu":"8"},
        "addresses":[
          {"type": "LegacyHostIP", "address":"127.0.0.2"},
          {"type": "another", "address":"127.0.0.3"}
        ]
      }
    }
  ],
  "users":[
    {
      "name": "myself",
      "user": {}
    },
    {
      "name": "e2e",
      "user": {"username": "admin", "password": "secret"}
    }
  ]
}

Function	Description	Example	Result
text	the plain text	kind is {.kind}	kind is List
@	the current object	{@}	the same as input
. or []	child operator	{.kind} or {['kind']}	List
..	recursive descent	{..name}	127.0.0.1 127.0.0.2 myself e2e

•    | wildcard. Get all objects| {.items[*].metadata.name} | [127.0.0.1 127.0.0.2]
  

[start:end :step] | subscript operator | {.users[0].name}| myself [,] | union operator | {.items[]['metadata.name', 'status.capacity']} | 127.0.0.1 127.0.0.2 map[cpu:4] map[cpu:8] ?() | filter | {.users[?(@.name=="e2e")].user.password} | secret range, end | iterate list | {range .items[]}[{.metadata.name}, {.status.capacity}] {end} | [127.0.0.1, map[cpu:4]] [127.0.0.2, map[cpu:8]] "" | quote interpreted string | {range .items[*]}{.metadata.name}{"\t"}{end} | 127.0.0.1 127.0.0.2

Below are some examples using jsonpath:

$ kubectl get pods -o json
$ kubectl get pods -o=jsonpath='{@}'
$ kubectl get pods -o=jsonpath='{.items[0]}'
$ kubectl get pods -o=jsonpath='{.items[0].metadata.name}'
$ kubectl get pods -o=jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.status.startTime}{"\n"}{end}'