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104 lines
3.4 KiB
Markdown
104 lines
3.4 KiB
Markdown
<!-- BEGIN MUNGE: UNVERSIONED_WARNING -->
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<!-- BEGIN STRIP_FOR_RELEASE -->
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<img src="http://kubernetes.io/img/warning.png" alt="WARNING"
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width="25" height="25">
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<img src="http://kubernetes.io/img/warning.png" alt="WARNING"
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width="25" height="25">
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<img src="http://kubernetes.io/img/warning.png" alt="WARNING"
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width="25" height="25">
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<img src="http://kubernetes.io/img/warning.png" alt="WARNING"
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width="25" height="25">
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<img src="http://kubernetes.io/img/warning.png" alt="WARNING"
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width="25" height="25">
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<h2>PLEASE NOTE: This document applies to the HEAD of the source tree</h2>
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If you are using a released version of Kubernetes, you should
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refer to the docs that go with that version.
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<!-- TAG RELEASE_LINK, added by the munger automatically -->
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<strong>
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The latest release of this document can be found
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[here](http://releases.k8s.io/release-1.1/docs/user-guide/jsonpath.md).
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Documentation for other releases can be found at
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[releases.k8s.io](http://releases.k8s.io).
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</strong>
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--
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<!-- END STRIP_FOR_RELEASE -->
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<!-- END MUNGE: UNVERSIONED_WARNING -->
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# JSONPath template syntax
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JSONPath template is composed of JSONPath expressions enclosed by {}.
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And we add three functions in addition to the original JSONPath syntax:
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1. The `$` operator is optional since the expression always start from the root object by default.
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2. We can use `""` to quote text inside JSONPath expression.
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3. We can use `range` operator to iterate list.
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The result object is printed as its String() function.
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Given the input:
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```json
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{
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"kind": "List",
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"items":[
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{
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"kind":"None",
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"metadata":{"name":"127.0.0.1"},
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"status":{
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"capacity":{"cpu":"4"},
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"addresses":[{"type": "LegacyHostIP", "address":"127.0.0.1"}]
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}
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},
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{
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"kind":"None",
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"metadata":{"name":"127.0.0.2"},
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"status":{
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"capacity":{"cpu":"8"},
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"addresses":[
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{"type": "LegacyHostIP", "address":"127.0.0.2"},
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{"type": "another", "address":"127.0.0.3"}
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]
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}
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}
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],
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"users":[
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{
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"name": "myself",
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"user": {}
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},
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{
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"name": "e2e",
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"user": {"username": "admin", "password": "secret"}
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}
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]
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}
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```
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Function | Description | Example | Result
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---------|--------------------|--------------------|------------------
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text | the plain text | kind is {.kind} | kind is List
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@ | the current object | {@} | the same as input
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. or [] | child operator | {.kind} or {['kind']}| List
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.. | recursive descent | {..name} | 127.0.0.1 127.0.0.2 myself e2e
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* | wildcard. Get all objects| {.items[*].metadata.name} | [127.0.0.1 127.0.0.2]
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[start:end :step] | subscript operator | {.users[0].name}| myself
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[,] | union operator | {.items[*]['metadata.name', 'status.capacity']} | 127.0.0.1 127.0.0.2 map[cpu:4] map[cpu:8]
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?() | filter | {.users[?(@.name=="e2e")].user.password} | secret
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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]]
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"" | quote interpreted string | {range .items[*]}{.metadata.name}{"\t"}{end} | 127.0.0.1 127.0.0.2
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<!-- BEGIN MUNGE: GENERATED_ANALYTICS -->
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[]()
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<!-- END MUNGE: GENERATED_ANALYTICS -->
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