JSONPath template is composed of JSONPath expressions enclosed by {}. And we add three functions in addition to the original JSONPath syntax:
$
operator is optional since the expression always starts from the root object by default.""
to quote text inside JSONPath expressions.range
operator to iterate lists.-index + listLength >= 0
.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}'