kubernetes/docs/user-guide/jsonpath.md

PLEASE NOTE: This document applies to the HEAD of the source tree

If you are using a released version of Kubernetes, you should refer to the docs that go with that version.

The latest release of this document can be found [here](http://releases.k8s.io/release-1.1/docs/user-guide/jsonpath.md).

Documentation for other releases can be found at releases.k8s.io.

JSONPath template syntax

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 start from the root object by default.
2. We can use "" to quote text inside JSONPath expression.
3. We can use range operator to iterate list.

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
""	quote	{"{"}	{
@	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]]