AWS::Serverless
transform
The AWS::Serverless
transform, which is a macro hosted by CloudFormation, takes an entire template
written in the Amazon Serverless Application Model (Amazon SAM) syntax and transforms and expands it into a compliant CloudFormation template. For more
information about serverless applications and Amazon SAM, see Deploying Lambda-based applications in the
Amazon Lambda Developer Guide, Amazon SAM
resource and property reference in the Amazon Serverless Application Model Developer Guide, and Amazon SAM transform
In the following example, the template uses Amazon 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: nodejs20.x CodeUri: 's3://testBucket/mySourceCode.zip'
When creating a change set from the template, CloudFormation expands the Amazon SAM syntax, as defined by
the transform. The processed template expands the AWS::Serverless::Function
resource, declaring an
Amazon 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": "nodejs20.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"