JSONPath Support [page]deterministic
The [kubectl](#gloss:kubectl) tool supports JSONPath templates as an output format.
A _JSONPath template_ is composed of JSONPath expressions enclosed by curly braces: `{` and `}`. Kubectl uses JSONPath expressions to filter on specific fields in the JSON object and format the output. In addition to the original JSONPath template syntax, the following functions and syntax are valid:
1. Use double quotes to quote text inside JSONPath expressions. 2. Use the `range`, `end` operators to iterate lists. 3. Use negative slice indices to step backwards through a list. Negative indices do _not_ "wrap around" a list and are valid as long as \\( ( - index + listLength ) \ge 0 \\).
> Note: - The `$` operator is optional since the expression always starts from the root object by default.
- The result object is printed as its `String()` function.
## Functions in Kubernetes JSONPath {#functions}
Given the JSON input:
```json { "kind": "List", "items":[ { "kind":"None", "metadata":{ "name":"127.0.0.1", "labels":{ "kubernetes.io/hostname":"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}`, `{['kind']}` or `{['name\.type']}` | `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` `\` | escape termination character | `{.items[0].metadata.labels.kubernetes\.io/hostname}` | `127.0.0.1`
## Using JSONPath expressions with kubectl {#use-with-kubectl}
Examples using `kubectl` and JSONPath expressions:
```shell 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="{.items[*]['metadata.name', 'status.capacity']}" kubectl get pods -o=jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.status.startTime}{"\n"}{e …(trimmed)