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# AWS::Synthetics::Canary Dependency
<a name="aws-properties-synthetics-canary-dependency"></a>

A structure that contains information about a dependency for a canary.

## Syntax
<a name="aws-properties-synthetics-canary-dependency-syntax"></a>

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

### JSON
<a name="aws-properties-synthetics-canary-dependency-syntax.json"></a>

```
{
  "[Reference](#cfn-synthetics-canary-dependency-reference)" : String,
  "[Type](#cfn-synthetics-canary-dependency-type)" : String
}
```

### YAML
<a name="aws-properties-synthetics-canary-dependency-syntax.yaml"></a>

```
  [Reference](#cfn-synthetics-canary-dependency-reference): String
  [Type](#cfn-synthetics-canary-dependency-type): String
```

## Properties
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`Reference`  <a name="cfn-synthetics-canary-dependency-reference"></a>
The dependency reference. For Lambda layers, this is the ARN of the Lambda layer. For more information about Lambda ARN format, see [Lambda](https://docs.amazonaws.cn/lambda/latest/api/API_Layer.html).  
*Required*: Yes  
*Type*: String  
*Pattern*: `arn:[a-zA-Z0-9-]+:lambda:[a-zA-Z0-9-]+:\d{12}:layer:[a-zA-Z0-9-_]+:[0-9]+`  
*Minimum*: `1`  
*Maximum*: `140`  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Type`  <a name="cfn-synthetics-canary-dependency-type"></a>
The type of dependency. Valid value is `LambdaLayer`.  
*Required*: No  
*Type*: String  
*Allowed values*: `LambdaLayer`  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)