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[zh] Sync using-api/cel.md

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@ -30,7 +30,7 @@ control plane's API server component remains available.
[通用表达式语言 (Common Expression Language, CEL)](https://github.com/google/cel-go)
用于声明 Kubernetes API 的验证规则、策略规则和其他限制或条件。
CEL 表达式在{{< glossary_tooltip text="API 服务器" term_id="kube-apiserver" >}}中直接进行评估，
CEL 表达式在 {{< glossary_tooltip text="API 服务器" term_id="kube-apiserver" >}}中直接进行处理，
这使得 CEL 成为许多可扩展性用例的便捷替代方案，而无需使用类似 Webhook 这种进程外机制。
只要控制平面的 API 服务器组件保持可用状态，你的 CEL 表达式就会继续执行。
@ -49,7 +49,7 @@ single expression that evaluates to a single value. CEL expressions are
typically short "one-liners" that inline well into the string fields of Kubernetes
API resources.
-->
## 语言概述 {#language-overview}
## 语言概述 {#language-overview}
[CEL 语言](https://github.com/google/cel-spec/blob/master/doc/langdef.md)的语法直观简单，
类似于 C、C++、Java、JavaScript 和 Go 中的表达式。
@ -68,7 +68,7 @@ different variables. See the API documentation of the API fields to learn which
variables are available for that field.
-->
对 CEL 程序的输入是各种 “变量”。包含 CEL 的每个 Kubernetes API 字段都在 API
文档中声明了字段可使用哪些变量。例如，在 CustomResourceDefinitions 的
文档中声明了字段可使用哪些变量。例如，在 CustomResourceDefinition 的
`x-kubernetes-validations[i].rules` 字段中，`self` 和 `oldSelf` 变量可用，
并且分别指代要由 CEL 表达式验证的自定义资源数据的前一个状态和当前状态。
其他 Kubernetes API 字段可能声明不同的变量。请查阅 API 字段的 API 文档以了解该字段可使用哪些变量。
@ -112,23 +112,60 @@ CEL 表达式示例：
{{< /table >}}
<!--
## CEL community libraries
## CEL options, language features, and libraries
Kubernetes CEL expressions have access to the following CEL community libraries:
CEL is configured with the following options, libraries and language features, introduced at the specified Kubernetes versions:
-->
## CEL 社区库 {#cel-community-libraries}
## CEL 选项、语言特性和库 {#cel-options-language-features-and-libraries}
Kubernetes CEL 表达式能够访问以下 CEL 社区库：
CEL 配置了以下选项、库和语言特性，这些特性是在所列的 Kubernetes 版本中引入的：
<!--
- CEL standard functions, defined in the [list of standard definitions](https://github.com/google/cel-spec/blob/master/doc/langdef.md#list-of-standard-definitions)
- CEL standard [macros](https://github.com/google/cel-spec/blob/v0.7.0/doc/langdef.md#macros)
- CEL [extended string function library](https://pkg.go.dev/github.com/google/cel-go/ext#Strings)
| CEL option, library or language feature | Included | Availablity |
|------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------|---------------------------|
| [Standard macros](https://github.com/google/cel-spec/blob/v0.7.0/doc/langdef.md#macros) | `has`, `all`, `exists`, `exists_one`, `map`, `filter` | All Kubernetes versions |
| [Standard functions](https://github.com/google/cel-spec/blob/master/doc/langdef.md#list-of-standard-definitions) | See [official list of standard definitions](https://github.com/google/cel-spec/blob/master/doc/langdef.md#list-of-standard-definitions) | All Kubernetes versions |
| [Homogeneous Aggregate Literals](https://pkg.go.dev/github.com/google/cel-go@v0.17.4/cel#HomogeneousAggregateLiterals) | | All Kubernetes versions |
| [Default UTC Time Zone](https://pkg.go.dev/github.com/google/cel-go@v0.17.4/cel#DefaultUTCTimeZone) | | All Kubernetes versions |
| [Eagerly Validate Declarations](https://pkg.go.dev/github.com/google/cel-go@v0.17.4/cel#EagerlyValidateDeclarations) | | All Kubernetes versions |
| [extended strings library](https://pkg.go.dev/github.com/google/cel-go/ext#Strings), Version 1 | `charAt`, `indexOf`, `lastIndexOf`, `lowerAscii`, `upperAscii`, `replace`, `split`, `join`, `substring`, `trim` | All Kubernetes versions |
| Kubernetes list library | See [Kubernetes list library](#kubernetes-list-library) | All Kubernetes versions |
| Kubernetes regex library | See [Kubernetes regex library](#kubernetes-regex-library) | All Kubernetes versions |
| Kubernetes URL library | See [Kubernetes URL library](#kubernetes-url-library) | All Kubernetes versions |
| Kubernetes authorizer library | See [Kubernetes authorizer library](#kubernetes-authorizer-library) | All Kubernetes versions |
| Kubernetes quantity library | See [Kubernetes quantity library](#kubernetes-quantity-library) | Kubernetes versions 1.29+ |
| CEL optional types | See [CEL optional types](https://pkg.go.dev/github.com/google/cel-go@v0.17.4/cel#OptionalTypes) | Kubernetes versions 1.29+ |
| CEL CrossTypeNumericComparisons | See [CEL CrossTypeNumericComparisons](https://pkg.go.dev/github.com/google/cel-go@v0.17.4/cel#CrossTypeNumericComparisons) | Kubernetes versions 1.29+ |
-->
- [标准定义列表](https://github.com/google/cel-spec/blob/master/doc/langdef.md#list-of-standard-definitions)中定义的
CEL 标准函数
- CEL 标准[宏](https://github.com/google/cel-spec/blob/v0.7.0/doc/langdef.md#macros)
- CEL [扩展字符串函数库](https://pkg.go.dev/github.com/google/cel-go/ext#Strings)
| CEL 选项、库或语言特性 | 包含的内容 | 可用性 |
| ------------------- | -------- | ----- |
| [标准宏](https://github.com/google/cel-spec/blob/v0.7.0/doc/langdef.md#macros) | `has`、`all`、`exists`、`exists_one`、`map`、`filter` | 所有 Kubernetes 版本 |
| [标准函数](https://github.com/google/cel-spec/blob/master/doc/langdef.md#list-of-standard-definitions) | 参见[官方标准定义列表](https://github.com/google/cel-spec/blob/master/doc/langdef.md#list-of-standard-definitions) | 所有 Kubernetes 版本 |
| [同质聚合字面量](https://pkg.go.dev/github.com/google/cel-go@v0.17.4/cel#HomogeneousAggregateLiterals) | | 所有 Kubernetes 版本 |
| [默认 UTC 时区](https://pkg.go.dev/github.com/google/cel-go@v0.17.4/cel#DefaultUTCTimeZone) | | 所有 Kubernetes 版本 |
| [迫切验证声明](https://pkg.go.dev/github.com/google/cel-go@v0.17.4/cel#EagerlyValidateDeclarations) | | 所有 Kubernetes 版本 |
| [扩展字符串库](https://pkg.go.dev/github.com/google/cel-go/ext#Strings)，v1 | `charAt`、`indexOf`、`lastIndexOf`、`lowerAscii`、`upperAscii`、`replace`、`split`、`join`、`substring`、`trim` | 所有 Kubernetes 版本 |
| Kubernetes 列表库 | 参见 [Kubernetes 列表库](#kubernetes-list-library) | 所有 Kubernetes 版本 |
| Kubernetes 正则表达式库 | 参见 [Kubernetes 正则表达式库](#kubernetes-regex-library) | 所有 Kubernetes 版本 |
| [Kubernetes URL 库] | 参见 [Kubernetes URL 库](#kubernetes-url-library) | 所有 Kubernetes 版本 |
| Kubernetes 鉴权组件库 | 参见 [Kubernetes 鉴权组件库](#kubernetes-authorizer-library) | 所有 Kubernetes 版本 |
| Kubernetes 数量库 | 参见 [Kubernetes 数量库](#kubernetes-quantity-library) | Kubernetes v1.29+ |
| CEL 可选类型 | 参见 [CEL 可选类型](https://pkg.go.dev/github.com/google/cel-go@v0.17.4/cel#OptionalTypes) | Kubernetes v1.29+ |
| CEL CrossTypeNumericComparisons | 参见 [CEL CrossTypeNumericComparisons](https://pkg.go.dev/github.com/google/cel-go@v0.17.4/cel#CrossTypeNumericComparisons) | Kubernetes v1.29+ |
<!--
CEL functions, features and language settings support Kubernetes control plane
rollbacks. For example, _CEL Optional Values_ was introduced at Kubernetes 1.29
and so only API servers at that version or newer will accept write requests to
CEL expressions that use _CEL Optional Values_. However, when a cluster is
rolled back to Kubernetes 1.28 CEL expressions using "CEL Optional Values" that
are already stored in API resources will continue to evaluate correctly.
-->
CEL 函数、特性和语言设置支持 Kubernetes 控制平面回滚。
例如，__CEL 可选值（Optional Values）__ 是在 Kubernetes 1.29 引入的，因此只有该版本或更新的
API 服务器才会接受使用 __CEL Optional Values__ 的 CEL 表达式的写入请求。
但是，当集群回滚到 Kubernetes 1.28 时，已经存储在 API 资源中的使用了
"CEL Optional Values" 的 CEL 表达式将继续正确评估。
<!--
## Kubernetes CEL libraries
@ -136,7 +173,7 @@ Kubernetes CEL 表达式能够访问以下 CEL 社区库：
In additional to the CEL community libraries, Kubernetes includes CEL libraries
that are available everywhere CEL is used in Kubernetes.
-->
## Kubernetes CEL 库 {#kubernetes-cel-libraries}
## Kubernetes CEL 库 {#kubernetes-cel-libraries}
除了 CEL 社区库之外，Kubernetes 还包括在 Kubernetes 中使用 CEL 时所有可用的 CEL 库。
@ -151,7 +188,7 @@ The list library also includes `min`, `max` and `sum`. Sum is supported on all
number types as well as the duration type. Min and max are supported on all
comparable types.
-->
### Kubernetes 列表库 {#kubernetes-list-library}
### Kubernetes 列表库 {#kubernetes-list-library}
列表库包括 `indexOf` 和 `lastIndexOf`，这两个函数的功能类似于同名的字符串函数。
这些函数返回提供的元素在列表中的第一个或最后一个位置索引。
@ -205,7 +242,7 @@ regex operations.
Examples:
-->
### Kubernetes 正则表达式库 {#kubernete-regex-library}
### Kubernetes 正则表达式库 {#kubernete-regex-library}
除了 CEL 标准库提供的 `matches` 函数外，正则表达式库还提供了 `find` 和 `findAll`，
使得更多种类的正则表达式运算成为可能。
@ -245,7 +282,7 @@ To make it easier and safer to process URLs, the following functions have been a
- `url(string) URL` converts a string to a URL or results in an error if the
string is not a valid URL.
-->
### Kubernetes URL 库 {#kubernetes-url-library}
### Kubernetes URL 库 {#kubernetes-url-library}
为了更轻松、更安全地处理 URL，添加了以下函数：
@ -296,7 +333,7 @@ the authorizer may be used to perform authorization checks for the principal
API resource checks are performed as follows:
-->
### Kubernetes 鉴权组件库
### Kubernetes 鉴权组件库 {#kubernetes-authorizer-library}
在 API 中使用 CEL 表达式，可以使用类型为 `Authorizer` 的变量，
这个鉴权组件可用于对请求的主体（已认证用户）执行鉴权检查。
@ -318,7 +355,7 @@ API 资源检查的过程如下：
注意这些函数将返回接收者的类型，并且可以串接起来：
- `ResourceCheck.subresource(string) ResourceCheck`
- `ResourceCheck.namespace(string) ResourceCheck`
- `ResourceCheck.name(string) ResourceCheck`
- `ResourceCheck.name(string) ResourceCheck`
3. 调用 `ResourceCheck.check(verb string) Decision` 来执行鉴权检查。
4. 调用 `allowed() bool` 或 `reason() string` 来查验鉴权检查的结果。
@ -331,7 +368,7 @@ Non-resource authorization performed are used as follows:
-->
对非资源访问的鉴权过程如下：
1. 仅指定路径：`Authorizer.path(string) PathCheck`
1. 仅指定路径：`Authorizer.path(string) PathCheck`。
1. 调用 `PathCheck.check(httpVerb string) Decision` 来执行鉴权检查。
1. 调用 `allowed() bool` 或 `reason() string` 来查验鉴权检查的结果。
@ -366,6 +403,98 @@ godoc for more information.
更多信息请参阅 Go 文档：
[Kubernetes Authz library](https://pkg.go.dev/k8s.io/apiserver/pkg/cel/library#Authz)。
<!--
### Kubernetes quantity library
Kubernetes 1.28 adds support for manipulating quantity strings (ex 1.5G, 512k, 20Mi)
-->
### Kubernetes 数量库 {#kubernetes-quantity-library}
Kubernetes 1.28 添加了对数量字符串（例如 1.5G、512k、20Mi）的操作支持。
<!--
- `isQuantity(string)` checks if a string is a valid Quantity according to [Kubernetes'
resource.Quantity](https://pkg.go.dev/k8s.io/apimachinery/pkg/api/resource#Quantity).
- `quantity(string) Quantity` converts a string to a Quantity or results in an error if the
string is not a valid quantity.
-->
- `isQuantity(string)` 根据 [Kubernetes 的 resource.Quantity](https://pkg.go.dev/k8s.io/apimachinery/pkg/api/resource#Quantity)，
检查字符串是否是有效的 Quantity。
- `quantity(string) Quantity` 将字符串转换为 Quantity，如果字符串不是有效的数量，则会报错。
<!--
Once parsed via the `quantity` function, the resulting Quantity object has the
following library of member functions:
-->
一旦通过 `quantity` 函数解析，得到的 Quantity 对象将具有以下成员函数库：
<!--
{{< table caption="Available member functions of a Quantity" >}}
| Member Function | CEL Return Value | Description |
|-------------------------------|-------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| `isInteger()` | bool | returns true if and only if asInteger is safe to call without an error |
| `asInteger()` | int | returns a representation of the current value as an int64 if possible or results in an error if conversion would result in overflow or loss of precision. |
| `asApproximateFloat()` | float | returns a float64 representation of the quantity which may lose precision. If the value of the quantity is outside the range of a float64 +Inf/-Inf will be returned. |
| `sign()` | int | Returns `1` if the quantity is positive, `-1` if it is negative. `0` if it is zero |
| `add(<Quantity>)` | Quantity | Returns sum of two quantities |
| `add(<int>)` | Quantity | Returns sum of quantity and an integer |
| `sub(<Quantity>)` | Quantity | Returns difference between two quantities |
| `sub(<int>)` | Quantity | Returns difference between a quantity and an integer |
| `isLessThan(<Quantity>)` | bool | Returns true if and only if the receiver is less than the operand |
| `isGreaterThan(<Quantity>)` | bool | Returns true if and only if the receiver is greater than the operand |
| `compareTo(<Quantity>)` | int | Compares receiver to operand and returns 0 if they are equal, 1 if the receiver is greater, or -1 if the receiver is less than the operand |
{{< /table >}}
-->
{{< table caption="Quantity 的可用成员函数" >}}
| 成员函数 | CEL 返回值 | 描述 |
| ------------------------ | --------- | --- |
| `isInteger()` | bool | 仅当 asInteger 可以被安全调用且不出错时，才返回 true |
| `asInteger()` | int | 将当前值作为 int64 的表示返回，如果转换会导致溢出或精度丢失，则会报错 |
| `asApproximateFloat()` | float | 返回数量的 float64 表示，可能会丢失精度。如果数量的值超出了 float64 的范围，则返回 +Inf/-Inf |
| `sign()` | int | 如果数量为正，则返回 1；如果数量为负，则返回 -1；如果数量为零，则返回 0 |
| `add(<Quantity>)` | Quantity | 返回两个数量的和 |
| `add(<int>)` | Quantity | 返回数量和整数的和 |
| `sub(<Quantity>)` | Quantity | 返回两个数量的差 |
| `sub(<int>)` | Quantity | 返回数量减去整数的差 |
| `isLessThan(<Quantity>)` | bool | 如果接收值小于操作数，则返回 true |
| `isGreaterThan(<Quantity>)`| bool | 如果接收值大于操作数，则返回 true |
| `compareTo(<Quantity>)` | int | 将接收值与操作数进行比较，如果它们相等，则返回 0；如果接收值大于操作数，则返回 1；如果接收值小于操作数，则返回 -1 |
{{< /table >}}
<!--
Examples:
-->
例如：
<!--
{{< table caption="Examples of CEL expressions using URL library functions" >}}
| CEL Expression | Purpose |
|---------------------------------------------------------------------------|-------------------------------------------------------|
| `quantity("500000G").isInteger()` | Test if conversion to integer would throw an error |
| `quantity("50k").asInteger()` | Precise conversion to integer |
| `quantity("9999999999999999999999999999999999999G").asApproximateFloat()` | Lossy conversion to float |
| `quantity("50k").add("20k")` | Add two quantities |
| `quantity("50k").sub(20000)` | Subtract an integer from a quantity |
| `quantity("50k").add(20).sub(quantity("100k")).sub(-50000)` | Chain adding and subtracting integers and quantities |
| `quantity("200M").compareTo(quantity("0.2G"))` | Compare two quantities |
| `quantity("150Mi").isGreaterThan(quantity("100Mi"))` | Test if a quantity is greater than the receiver |
| `quantity("50M").isLessThan(quantity("100M"))` | Test if a quantity is less than the receiver |
{{< /table >}}
-->
{{< table caption="使用 URL 库函数的 CEL 表达式示例" >}}
| CEL 表达式 | 用途 |
|---------------------------------------------------------------------------| -------------------- |
| `quantity("500000G").isInteger()` | 测试转换为整数是否会报错 |
| `quantity("50k").asInteger()` | 精确转换为整数 |
| `quantity("9999999999999999999999999999999999999G").asApproximateFloat()` | 松散转换为浮点数 |
| `quantity("50k").add("20k")` | 两个数量相加 |
| `quantity("50k").sub(20000)` | 从数量中减去整数 |
| `quantity("50k").add(20).sub(quantity("100k")).sub(-50000)` | 链式相加和减去整数和数量 |
| `quantity("200M").compareTo(quantity("0.2G"))` | 比较两个数量 |
| `quantity("150Mi").isGreaterThan(quantity("100Mi"))` | 测试数量是否大于接收值 |
| `quantity("50M").isLessThan(quantity("100M"))` | 测试数量是否小于接收值 |
{{< /table >}}
<!--
## Type checking
@ -376,16 +505,16 @@ example, [CustomResourceDefinitions Validation
Rules](/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/#validation-rules)
are fully type checked.
-->
## 类型检查 {#type-checking}
## 类型检查 {#type-checking}
CEL 是一种[逐渐类型化的语言](https://github.com/google/cel-spec/blob/master/doc/langdef.md#gradual-type-checking)。
一些 Kubernetes API 字段包含完全经过类型检查的 CEL 表达式。
例如，[CustomResourceDefinitions 验证规则](/zh-cn/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/#validation-rules)就是完全经过类型检查的。
例如，[CustomResourceDefinition 验证规则](/zh-cn/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/#validation-rules)就是完全经过类型检查的。
<!--
Some Kubernetes API fields contain partially type checked CEL expressions. A
partially type checked expression is an experessions where some of the variables
partially type checked expression is an expressions where some of the variables
are statically typed but others are dynamically typed. For example, in the CEL
expressions of
[ValidatingAdmissionPolicies](/docs/reference/access-authn-authz/validating-admission-policy/)
@ -397,7 +526,7 @@ that `object` refers to, because `object` is dynamically typed.
-->
一些 Kubernetes API 字段包含部分经过类型检查的 CEL 表达式。
部分经过类型检查的表达式是指一些变量是静态类型，而另一些变量是动态类型的表达式。
例如在 [ValidatingAdmissionPolicies](/zh-cn/docs/reference/access-authn-authz/validating-admission-policy/)
例如在 [ValidatingAdmissionPolicy](/zh-cn/docs/reference/access-authn-authz/validating-admission-policy/)
的 CEL 表达式中，`request` 变量是有类型的，但 `object` 变量是动态类型的。
因此，包含 `request.namex` 的表达式将无法通过类型检查，因为 `namex` 字段未定义。
然而，即使对于 `object` 所引用的资源种类没有定义 `namex` 字段，
@ -418,7 +547,7 @@ has(object.namex) ? object.namex == 'special' : request.name == 'special'
<!--
## Type system integration
-->
## 类型系统集成 {#type-system-integration}
## 类型系统集成 {#type-system-integration}
<!--
{{< table caption="Table showing the relationship between OpenAPIv3 types and CEL types" >}}
@ -511,7 +640,7 @@ Only Kubernetes resource property names of the form
names are escaped according to the following rules when accessed in the
expression:
-->
## 转义 {#escaping}
## 转义 {#escaping}
仅形如 `[a-zA-Z_.-/][a-zA-Z0-9_.-/]*` 的 Kubernetes 资源属性名可以从 CEL 中访问。
当在表达式中访问可访问的属性名时，会根据以下规则进行转义：
@ -578,7 +707,7 @@ excessive resource consumption during evaluation. CEL's resource constraint
features are used to prevent CEL evaluation from consuming excessive API server
resources.
-->
## 资源约束 {#resource-constraints}
## 资源约束 {#resource-constraints}
CEL 不是图灵完备的，提供了多种生产安全控制手段来限制执行时间。
CEL 的**资源约束**特性提供了关于表达式复杂性的反馈，并帮助保护 API 服务器免受过度的资源消耗。
@ -625,7 +754,7 @@ expression. If the CEL interpreter executes too many instructions, the runtime
cost budget will be exceeded, execution of the expressions will be halted, and
an error will result.
-->
### 运行时成本预算 {#runtime-cost-budget}
### 运行时成本预算 {#runtime-cost-budget}
所有由 Kubernetes 评估的 CEL 表达式都受到运行时成本预算的限制。
运行时成本预算是通过在解释 CEL 表达式时增加成本单元计数器来计算实际 CPU 利用率的估算值。
@ -657,7 +786,7 @@ expression to the API resources. This feature offers a stronger assurance that
CEL expressions written to the API resource will be evaluate at runtime without
exceeding the runtime cost budget.
-->
### 估算的成本限制 {#estimated-cost-limits}
### 估算的成本限制 {#estimated-cost-limits}
对于某些 Kubernetes 资源，API 服务器还可能检查 CEL 表达式的最坏情况估计运行时间是否过于昂贵而无法执行。
如果是，则 API 服务器会拒绝包含 CEL 表达式的创建或更新操作，以防止 CEL 表达式被写入 API 资源。