AWS::Serverless::LayerVersion

Creates a Lambda LayerVersion that contains library or runtime code needed by a Lambda Function.

The AWS::Serverless::LayerVersion resource also supports the Metadata resource attribute, so you can instruct AWS SAM to build layers included in your application. For more information about building layers, see Building layers.

Important Note: Since the release of the UpdateReplacePolicy resource attribute in AWS CloudFormation, AWS::Lambda::LayerVersion (recommended) offers the same benefits as AWS::Serverless::LayerVersion.

When a Serverless LayerVersion is transformed, SAM also transforms the logical id of the resource so that old LayerVersions are not automatically deleted by CloudFormation when the resource is updated.

Note

When you deploy to AWS CloudFormation, AWS SAM transforms your AWS SAM resources into AWS CloudFormation resources. For more information, see Generated AWS CloudFormation resources.

Syntax

To declare this entity in your AWS Serverless Application Model (AWS SAM) template, use the following syntax.

YAML

Type: AWS::Serverless::LayerVersion
Properties:
  CompatibleArchitectures: List
  CompatibleRuntimes: List
  ContentUri: String | LayerContent
  Description: String
  LayerName: String
  LicenseInfo: String
  RetentionPolicy: String

Properties

CompatibleArchitectures

Specifies the supported instruction set architectures for the layer version.

For more information about this property, see Lambda instruction set architectures in the AWS Lambda Developer Guide.

Valid values: x86_64, arm64

Type: List

Required: No

Default: x86_64

AWS CloudFormation compatibility: This property is passed directly to the CompatibleArchitectures property of an AWS::Lambda::LayerVersion resource.

CompatibleRuntimes

List of runtimes compatible with this LayerVersion.

Type: List

Required: No

AWS CloudFormation compatibility: This property is passed directly to the CompatibleRuntimes property of an AWS::Lambda::LayerVersion resource.

ContentUri

Amazon S3 Uri, path to local folder, or LayerContent object of the layer code.

If an Amazon S3 Uri or LayerContent object is provided, The Amazon S3 object referenced must be a valid ZIP archive that contains the contents of an Lambda layer.

If a path to a local folder is provided, for the content to be transformed properly the template must go through the workflow that includes sam build followed by either sam deploy or sam package. By default, relative paths are resolved with respect to the AWS SAM template's location.

Type: String | LayerContent

Required: Yes

AWS CloudFormation compatibility: This property is similar to the Content property of an AWS::Lambda::LayerVersion resource. The nested Amazon S3 properties are named differently.

Description

Description of this layer.

Type: String

Required: No

AWS CloudFormation compatibility: This property is passed directly to the Description property of an AWS::Lambda::LayerVersion resource.

LayerName

The name or Amazon Resource Name (ARN) of the layer.

Type: String

Required: No

Default: Resource logical id

AWS CloudFormation compatibility: This property is similar to the LayerName property of an AWS::Lambda::LayerVersion resource. If you don't specify a name, the logical id of the resource will be used as the name.

LicenseInfo

Information about the license for this LayerVersion.

Type: String

Required: No

AWS CloudFormation compatibility: This property is passed directly to the LicenseInfo property of an AWS::Lambda::LayerVersion resource.

RetentionPolicy

This property specifies whether old versions of your LayerVersion are retained or deleted when you delete a resource. If you need to retain old versions of your LayerVersion when updating or replacing a resource, you must have the UpdateReplacePolicy attribute enabled. For information on doing this, refer to UpdateReplacePolicy attribute in the AWS CloudFormation User Guide.

Valid values: Retain or Delete

Type: String

Required: No

AWS CloudFormation compatibility: This property is unique to AWS SAM and doesn't have an AWS CloudFormation equivalent.

Additional notes: When you specify Retain, AWS SAM adds a Resource attributes of DeletionPolicy: Retain to the transformed AWS::Lambda::LayerVersion resource.

Return Values

Ref

When the logical ID of this resource is provided to the Ref intrinsic function, it returns the resource ARN of the underlying Lambda LayerVersion.

For more information about using the Ref function, see Ref in the AWS CloudFormation User Guide.

Examples

LayerVersionExample

Example of a LayerVersion

YAML

Properties:
  LayerName: MyLayer
  Description: Layer description
  ContentUri: 's3://my-bucket/my-layer.zip'
  CompatibleRuntimes:
    - nodejs10.x
    - nodejs12.x
  LicenseInfo: 'Available under the MIT-0 license.'
  RetentionPolicy: Retain