could I write some code in cloudformation template？

Question

I write some code in cloudformation template,but away wrong, can you tell me why?
```
    MyS3Bucket:
        Type: AWS::S3::Bucket
        Properties:
            BucketName: test
        DeletionPolicy: Retain

LambdaExecutionRole:
        Type: AWS::IAM::Role
        Properties:
            AssumeRolePolicyDocument:
                Version: '2012-10-17'
                Statement:
                    - Effect: Allow
                      Principal:
                          Service: lambda.amazonaws.com
                      Action: sts:AssumeRole
            ManagedPolicyArns:
                - arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole
            Path: /
        DeletionPolicy: Retain

LambdaFunction:
        Type: AWS::Lambda::Function
        Properties:
            FunctionName: MyS3CopyFunction
            Runtime: python3.8
            Role: !GetAtt LambdaExecutionRole.Arn
            Handler: index.lambda_handler
            Code:
                ZipFile: !Join 
                  - |+

- - import boto3

- 'def lambda_handler(event, context):'
                    - '    source_bucket = setting-params'
                    - '    destination_bucket = test'
                    - '    s3 = boto3.client('s3')'
                    - '    s3.Object(destination_bucket).copy_from(CopySource=f"{source_bucket}")'

Timeout: 30
        DeletionPolicy: Retain

S3EventTrigger:
        Type: AWS::Lambda::EventSourceMapping
        Properties:
            BatchSize: 1
            EventSourceArn: !GetAtt SettingParams.Arn
            FunctionName: !Ref LambdaFunction
        DeletionPolicy: Retain
```

Answer

Hi,

to inline your Lambda code directly in the CloudFormation template, follow this example https://github.com/aws-samples/aws-cloudformation-inline-python-lambda-example/blob/main/base-cfn-lambda.yml from this repo https://github.com/aws-samples/aws-cloudformation-inline-python-lambda-example

```
.....

Code:
        ZipFile: |
            # Imports
            import os
            import boto3
            import botocore
            import logging
            import random
            import string

# Set up clients and resources
            ddbclient = boto3.client('dynamodb')

# Set up the logger
            logger = logging.getLogger()
            logger.setLevel(logging.INFO)
            #logger.setLevel(logging.DEBUG) # Very verbose

# Env variables from CFN
            tablename = os.environ.get('TableName')
            keyname = os.environ.get('KeyName')

def lambda_handler(event, context):
                # Generate a random string to ensure no duplicates are put into DDB table
                randomstring = (''.join(random.choice(string.ascii_letters) for i in range(10)))
                logger.info('Random string generated: %s', randomstring)
                
                def ddb_client(tablename, keyname, stringdata):
                    response = ddbclient.put_item(
                    Item={
                        keyname: {
                            'S': stringdata
                        }
                    },
                    ReturnConsumedCapacity='TOTAL',
                    TableName=tablename
                    )
                    return(response)
                
                try:    
                    ddb_response = ddb_client(tablename, keyname, randomstring)
                    logger.info(ddb_response)
                except botocore.exceptions.ClientError as error:
                    # Put your error handling logic here
                    raise error
                    
                return(ddb_response)
    
  DynamoDBTable:
    Type: AWS::DynamoDB::Table

......

```

Hope it helps,
Didier

could I write some code in cloudformation template？

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