README.md

DynamoDB Stream → Lambda

Capturing the write (Put, Delete, Update) operation of a DynamoDB stream that will be processed by a Lambda function. The Lambda Function reads the records from the stream and invokes the function synchronously with an event that contains stream records.

Sample CloudWatch Logs

DynamoDB Insert

{
    "log_code": "DynamoDBStreamRecord",
    "log_msg": "Events from the DynamoDB Table",
    "log_level": "INFO",
    "log_keys": {
        "record": {
            "awsRegion": "us-east-1",
            "dynamodb": {
                "ApproximateCreationDateTime": 1689103530,
                "Keys": {
                    "referenceId": {
                        "S": "sample-reference-id-12345"
                    }
                },
                "NewImage": {
                    "change": {
                        "N": "249.5"
                    },
                    "customer_id": {
                        "S": "customer-12345"
                    },
                    "quantity": {
                        "N": "25"
                    },
                    "referenceId": {
                        "S": "sample-reference-id-12345"
                    },
                    "total": {
                        "N": "1250.5"
                    }
                },
                "SequenceNumber": "100000000006899888825",
                "SizeBytes": 126,
                "StreamViewType": "NEW_IMAGE"
            },
            "eventID": "12ab34c567de89f10fedc11b1a07e92b",
            "eventName": "INSERT",
            "eventSource": "aws:dynamodb",
            "eventVersion": "1.1",
            "eventSourceARN": "arn:aws:dynamodb:us-east-1:123456789101:table/orders/stream/2023-05-19T02:24:40.803"
        }
    },
    "log_timestamp": "2023-05-19 02:30:49"
}

DynamoDB Modify

{
    "log_code": "DynamoDBStreamRecord",
    "log_msg": "Events from the DynamoDB Table",
    "log_level": "INFO",
    "log_keys": {
        "record": {
            "awsRegion": "us-east-1",
            "dynamodb": {
                "ApproximateCreationDateTime": 1689103530,
                "Keys": {
                    "referenceId": {
                        "S": "sample-reference-id-12345"
                    }
                },
                "NewImage": {
                    "cash": {
                        "N": "1500"
                    },
                    "change": {
                        "N": "249.5"
                    },
                    "customer_id": {
                        "S": "customer-12345"
                    },
                    "quantity": {
                        "N": "25"
                    },
                    "referenceId": {
                        "S": "sample-reference-id-12345"
                    },
                    "total": {
                        "N": "1250.5"
                    }
                },
                "SequenceNumber": "200000000006399151338",
                "SizeBytes": 132,
                "StreamViewType": "NEW_IMAGE"
            },
            "eventID": "12ab34c567de89f10fedc11b1a07e92b",
            "eventName": "MODIFY",
            "eventSource": "aws:dynamodb",
            "eventVersion": "1.1",
            "eventSourceARN": "arn:aws:dynamodb:us-east-1:123456789101:table/orders/stream/2023-05-19T02:24:40.803"
        }
    },
    "log_timestamp": "2023-05-19 02:31:40"
}

DynamoDB Remove

{
    "log_code": "DynamoDBStreamRecord",
    "log_msg": "Events from the DynamoDB Table",
    "log_level": "INFO",
    "log_keys": {
        "record": {
            "awsRegion": "us-east-1",
            "dynamodb": {
                "ApproximateCreationDateTime": 1689103530,
                "Keys": {
                    "referenceId": {
                        "S": "sample-reference-id-12345"
                    }
                },
                "SequenceNumber": "300000000006899888825",
                "SizeBytes": 36,
                "StreamViewType": "NEW_IMAGE"
            },
            "eventID": "12ab34c567de89f10fedc11b1a07e92b",
            "eventName": "REMOVE",
            "eventSource": "aws:dynamodb",
            "eventVersion": "1.1",
            "eventSourceARN": "arn:aws:dynamodb:us-east-1:123456789101:table/orders/stream/2023-05-19T02:24:40.803"
        }
    },
    "log_timestamp": "2023-05-19 02:32:10"
}

AWS CDK API / Developer Reference

• AWS Lambda
• AWS DynamoDB
• AWS Lambda Event Sources

AWS SDK v2 API / Developer Reference

• AWS Lambda Events
• Getting Started with the AWS SDK for Go V2

AWS Documentation Developer Guide

• Core components of Amazon DynamoDB
• Using AWS Lambda with Amazon DynamoDB
• Change data capture for DynamoDB Streams
• Best practices for designing and using partition keys effectively

Useful commands

• npm run build compile typescript to js
• npm run watch watch for changes and compile
• npm run test perform the jest unit tests
• cdk deploy deploy this stack to your default AWS account/region
• cdk diff compare deployed stack with current state
• cdk synth emits the synthesized CloudFormation template

Deploy

Using make command

1. Install all the dependencies, bootstrap your project, and synthesized CloudFormation template.

   # Without passing "profile" parameter
   dev@dev:~:aws-cdk-samples/dynamodb/dynamodb-stream-lambda$ make init
   
   # With "profile" parameter
   dev@dev:~:aws-cdk-samples/dynamodb/dynamodb-stream-lambda$ make init profile=[profile_name]

2. Deploy the project.

   # Without passing "profile" parameter
   dev@dev:~:aws-cdk-samples/dynamodb/dynamodb-stream-lambda$ make deploy
   
   # With "profile" parameter
   dev@dev:~:aws-cdk-samples/dynamodb/dynamodb-stream-lambda$ make deploy profile=[profile_name]