How to create and manage a Lambda Layer using AWS SAM

SAM-Lambda-Layer.yaml

## Manage your Lambda layer in SAM
## This creates a layer and the permissions for the layer. This particular permission opens it to the world.
## I then use 'sam package' and 'sam deploy' to create/update the layer

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: Lambda Layer

Resources:
  MyLayer:
    Type: AWS::Serverless::LayerVersion
    Properties:
        LayerName: layer-name
        Description: layer-description
        ContentUri: layer/                 ## Local folder containing layer contents
        CompatibleRuntimes:                ## Works with any of the supported languages
          - nodejs8.10
          - nodejs10.x
        LicenseInfo: 'MIT'
        RetentionPolicy: Retain

  AWSSDKLayerPermission:
    Type: "AWS::Lambda::LayerVersionPermission"
    Properties:
      Action: lambda:GetLayerVersion
      LayerVersionArn: !Ref MyLayer
      Principal: '*'

Thank's !