This is the new *Amazon CloudFormation Template Reference Guide*. Please update your bookmarks and links. For help getting started with CloudFormation, see the [Amazon CloudFormation User Guide](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/Welcome.html).

# AWS::WAFv2::RuleGroup Rule
<a name="aws-properties-wafv2-rulegroup-rule"></a>

A single rule, which you can use in a [AWS::WAFv2::WebACL](aws-resource-wafv2-webacl.md) or [AWS::WAFv2::RuleGroup](aws-resource-wafv2-rulegroup.md) to identify web requests that you want to manage in some way. Each rule includes one top-level [Statement](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-properties-wafv2-rulegroup-rule.html#cfn-wafv2-rulegroup-rule-statement) that Amazon WAF uses to identify matching web requests, and parameters that govern how Amazon WAF handles them. 

## Syntax
<a name="aws-properties-wafv2-rulegroup-rule-syntax"></a>

To declare this entity in your Amazon CloudFormation template, use the following syntax:

### JSON
<a name="aws-properties-wafv2-rulegroup-rule-syntax.json"></a>

```
{
  "[Action](#cfn-wafv2-rulegroup-rule-action)" : RuleAction,
  "[CaptchaConfig](#cfn-wafv2-rulegroup-rule-captchaconfig)" : CaptchaConfig,
  "[ChallengeConfig](#cfn-wafv2-rulegroup-rule-challengeconfig)" : ChallengeConfig,
  "[Name](#cfn-wafv2-rulegroup-rule-name)" : String,
  "[Priority](#cfn-wafv2-rulegroup-rule-priority)" : Integer,
  "[RuleLabels](#cfn-wafv2-rulegroup-rule-rulelabels)" : [ Label, ... ],
  "[Statement](#cfn-wafv2-rulegroup-rule-statement)" : Statement,
  "[VisibilityConfig](#cfn-wafv2-rulegroup-rule-visibilityconfig)" : VisibilityConfig
}
```

### YAML
<a name="aws-properties-wafv2-rulegroup-rule-syntax.yaml"></a>

```
  [Action](#cfn-wafv2-rulegroup-rule-action): 
    RuleAction
  [CaptchaConfig](#cfn-wafv2-rulegroup-rule-captchaconfig): 
    CaptchaConfig
  [ChallengeConfig](#cfn-wafv2-rulegroup-rule-challengeconfig): 
    ChallengeConfig
  [Name](#cfn-wafv2-rulegroup-rule-name): String
  [Priority](#cfn-wafv2-rulegroup-rule-priority): Integer
  [RuleLabels](#cfn-wafv2-rulegroup-rule-rulelabels): 
    - Label
  [Statement](#cfn-wafv2-rulegroup-rule-statement): 
    Statement
  [VisibilityConfig](#cfn-wafv2-rulegroup-rule-visibilityconfig): 
    VisibilityConfig
```

## Properties
<a name="aws-properties-wafv2-rulegroup-rule-properties"></a>

`Action`  <a name="cfn-wafv2-rulegroup-rule-action"></a>
The action that Amazon WAF should take on a web request when it matches the rule statement. Settings at the web ACL level can override the rule action setting.   
*Required*: No  
*Type*: [RuleAction](aws-properties-wafv2-rulegroup-ruleaction.md)  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`CaptchaConfig`  <a name="cfn-wafv2-rulegroup-rule-captchaconfig"></a>
Specifies how Amazon WAF should handle `CAPTCHA` evaluations. If you don't specify this, Amazon WAF uses the `CAPTCHA` configuration that's defined for the web ACL.   
*Required*: No  
*Type*: [CaptchaConfig](aws-properties-wafv2-rulegroup-captchaconfig.md)  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`ChallengeConfig`  <a name="cfn-wafv2-rulegroup-rule-challengeconfig"></a>
Specifies how Amazon WAF should handle `Challenge` evaluations. If you don't specify this, Amazon WAF uses the challenge configuration that's defined for the web ACL.   
*Required*: No  
*Type*: [ChallengeConfig](aws-properties-wafv2-rulegroup-challengeconfig.md)  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Name`  <a name="cfn-wafv2-rulegroup-rule-name"></a>
The name of the rule.   
If you change the name of a `Rule` after you create it and you want the rule's metric name to reflect the change, update the metric name in the rule's `VisibilityConfig` settings. Amazon WAF doesn't automatically update the metric name when you update the rule name.   
*Required*: Yes  
*Type*: String  
*Pattern*: `^[0-9A-Za-z_-]{1,128}$`  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Priority`  <a name="cfn-wafv2-rulegroup-rule-priority"></a>
If you define more than one `Rule` in a `WebACL`, Amazon WAF evaluates each request against the `Rules` in order based on the value of `Priority`. Amazon WAF processes rules with lower priority first. The priorities don't need to be consecutive, but they must all be different.  
*Required*: Yes  
*Type*: Integer  
*Minimum*: `0`  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`RuleLabels`  <a name="cfn-wafv2-rulegroup-rule-rulelabels"></a>
Labels to apply to web requests that match the rule match statement. Amazon WAF applies fully qualified labels to matching web requests. A fully qualified label is the concatenation of a label namespace and a rule label. The rule's rule group or web ACL defines the label namespace.   
Any rule that isn't a rule group reference statement or managed rule group statement can add labels to matching web requests.
Rules that run after this rule in the web ACL can match against these labels using a `LabelMatchStatement`.  
For each label, provide a case-sensitive string containing optional namespaces and a label name, according to the following guidelines:  
+ Separate each component of the label with a colon. 
+ Each namespace or name can have up to 128 characters.
+ You can specify up to 5 namespaces in a label.
+ Don't use the following reserved words in your label specification: `aws`, `waf`, `managed`, `rulegroup`, `webacl`, `regexpatternset`, or `ipset`.
For example, `myLabelName` or `nameSpace1:nameSpace2:myLabelName`.   
*Required*: No  
*Type*: Array of [Label](aws-properties-wafv2-rulegroup-label.md)  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Statement`  <a name="cfn-wafv2-rulegroup-rule-statement"></a>
The Amazon WAF processing statement for the rule, for example [ByteMatchStatement](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-properties-wafv2-webacl-statement.html#cfn-wafv2-webacl-statement-bytematchstatement) or [SizeConstraintStatement](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-properties-wafv2-webacl-statement.html#cfn-wafv2-webacl-statement-sizeconstraintstatement).   
*Required*: Yes  
*Type*: [Statement](aws-properties-wafv2-rulegroup-statement.md)  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`VisibilityConfig`  <a name="cfn-wafv2-rulegroup-rule-visibilityconfig"></a>
Defines and enables Amazon CloudWatch metrics and web request sample collection.   
If you change the name of a `Rule` after you create it and you want the rule's metric name to reflect the change, update the metric name as well. Amazon WAF doesn't automatically update the metric name.   
*Required*: Yes  
*Type*: [VisibilityConfig](aws-properties-wafv2-rulegroup-visibilityconfig.md)  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)