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::WAFRegional::WebACL Rule
<a name="aws-properties-wafregional-webacl-rule"></a>

A combination of `ByteMatchSet`, `IPSet`, and/or `SqlInjectionMatchSet` objects that identify the web requests that you want to allow, block, or count. For example, you might create a `Rule` that includes the following predicates:
+ An `IPSet` that causes Amazon WAF to search for web requests that originate from the IP address `192.0.2.44`
+ A `ByteMatchSet` that causes Amazon WAF to search for web requests for which the value of the `User-Agent` header is `BadBot`.

To match the settings in this `Rule`, a request must originate from `192.0.2.44` AND include a `User-Agent` header for which the value is `BadBot`.

## Syntax
<a name="aws-properties-wafregional-webacl-rule-syntax"></a>

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

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

```
{
  "[Action](#cfn-wafregional-webacl-rule-action)" : {{Action}},
  "[Priority](#cfn-wafregional-webacl-rule-priority)" : {{Integer}},
  "[RuleId](#cfn-wafregional-webacl-rule-ruleid)" : {{String}}
}
```

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

```
  [Action](#cfn-wafregional-webacl-rule-action): {{
    Action}}
  [Priority](#cfn-wafregional-webacl-rule-priority): {{Integer}}
  [RuleId](#cfn-wafregional-webacl-rule-ruleid): {{String}}
```

## Properties
<a name="aws-properties-wafregional-webacl-rule-properties"></a>

`Action`  <a name="cfn-wafregional-webacl-rule-action"></a>
The action that Amazon WAF takes when a web request matches all conditions in the rule, such as allow, block, or count the request.  
*Required*: Yes  
*Type*: [Action](aws-properties-wafregional-webacl-action.md)  
*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-wafregional-webacl-rule-priority"></a>
The order in which Amazon WAF evaluates the rules in a web ACL. Amazon WAF evaluates rules with a lower value before rules with a higher value. The value must be a unique integer. If you have multiple rules in a web ACL, the priority numbers do not need to be consecutive.   
*Required*: Yes  
*Type*: Integer  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`RuleId`  <a name="cfn-wafregional-webacl-rule-ruleid"></a>
The ID of an Amazon WAF Regional rule to associate with a web ACL.   
*Required*: Yes  
*Type*: String  
*Pattern*: `.*\S.*`  
*Minimum*: `1`  
*Maximum*: `128`  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)