AWS::Serverless
transform
The AWS::Serverless
transform, which is a macro hosted by CloudFormation, takes an
entire template written in the AWS Serverless Application Model (AWS SAM) syntax and transforms and expands it into a
compliant CloudFormation template. For more information about serverless applications and
AWS SAM, see Deploying
Lambda-based applications in the AWS Lambda Developer Guide and AWS SAM resource and property reference in the AWS Serverless Application Model Developer Guide.
In the following example, the template uses AWS SAM syntax to simplify the declaration of a Lambda function and its execution role.
Transform: AWS::Serverless-2016-10-31 Resources: MyServerlessFunctionLogicalID: Type: AWS::Serverless::Function Properties: Handler: index.handler Runtime: nodejs18.x CodeUri: 's3://testBucket/mySourceCode.zip'
When creating a change set from the template, CloudFormation expands the AWS SAM
syntax, as defined by the transform. The processed template expands the
AWS::Serverless::Function
resource, declaring an AWS Lambda function and
an execution role.
{ "Resources": { "MyServerlessFunctionLogicalID": { "Type": "AWS::Lambda::Function", "Properties": { "Handler": "index.handler", "Code": { "S3Bucket": "testBucket", "S3Key": "mySourceCode.zip" }, "Role": { "Fn::GetAtt": ["FunctionNameRole", "Arn"] }, "Runtime": "nodejs18.x" } }, "FunctionNameRole": { "Type": "AWS::IAM::Role", "Properties": { "ManagedPolicyArns": ["arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"], "AssumeRolePolicyDocument": { "Version": "2012-10-17", "Statement": [{ "Action": ["sts:AssumeRole"], "Effect": "Allow", "Principal": { "Service": ["lambda.amazonaws.com"] } }] } } } } }
Syntax
The value for the transform declaration must be a literal string. You can't use a parameter or function to specify a transform value. The following snippet is an example of a transform declaration:
JSON
"Transform" : "AWS::Serverless-2016-10-31"
YAML
Transform: "AWS::Serverless-2016-10-31"