CloudFormation template: reduce boilerplate code

Question

I'm trying to compose CF template to deploy a serverless system consisting of several Lambdas. In my case, Lambda resource descriptions share a lot of properties; the only difference is filename and handler function.

How can I define something like common set of parameters in my template?

This boilerplate is awful:

  LambdaCreateUser:
    Type: AWS::Lambda::Function
    Properties: 
      Code:
        S3Bucket:
          Ref: BucketForLambdas
        S3Key: create_user.zip
      Handler: create_user.lambda_handler
      Runtime: python3.7
      Role: 
        Fn::GetAtt: [ LambdaRole , "Arn" ]
      Environment:
        Variables: { "EnvTable": !Ref EnvironmentTable, "UsersTable": !Ref UsersTable }
  LambdaDeleteUser:
    Type: AWS::Lambda::Function
    Properties: 
      Code:
        S3Bucket:
          Ref: BucketForLambdas
        S3Key: delete_user.zip 
      Handler: delete_user.lambda_handler  
      Runtime: python3.7   
      Role:
        Fn::GetAtt: [ LambdaRole , "Arn" ]
      Environment:
        Variables: { "EnvTable": !Ref EnvironmentTable, "UsersTable": !Ref UsersTable }

Answer 1

What you're looking for is AWS SAM which is a layer of syntactic sugar on top on CloudFormation. A basic representation of your template with AWS SAM would look like this:

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

Globals:
  Function:
    Runtime: python3.7
    Environment:
      Variables:
        EnvTable: !Ref EnvironmentTable
        UsersTable: !Ref UsersTable

Resources:
  LambdaCreateUser:
    Type: AWS::Serverless::Function
    Properties: 
      Code:
        S3Bucket:
          Ref: BucketForLambdas
        S3Key: create_user.zip
      Handler: create_user.lambda_handler
      Role: !GetAtt LambdaRole.Arn
  LambdaDeleteUser:
    Type: AWS::Serverless::Function
    Properties: 
      Code:
        S3Bucket:
          Ref: BucketForLambdas
        S3Key: delete_user.zip 
      Handler: delete_user.lambda_handler  
      Role: !GetAtt LambdaRole.Arn

But that's not the end. You can replace the code definition with a path to your code or even inline code and use sam build and sam package to build and upload your artifacts. You can also probably replace the role definition with SAM policy templates for further reduction of boilerplate code.