Guided Lab: Processing Amazon DynamoDB Streams with AWS Lambda

1. Navigate to Amazon DynamoDB

2. Click “Create table” to create a new DynamoDB table

3. Enter the following configuration for the Table details:

• Table name: This could be anything relevant to the data you’re storing. For example, we will put “Foods”.
• Partition key: This could be any attribute of your data. For example, let’s put “Desserts”. Also, don’t change its data type on the right side as it should remain as “String”
• Leave the other configurations as default and click Create Table at the bottom of the page.

4. Select the DynamoDB table that was created.

5. Go to the Exports and Streams section, scroll down to ‘DynamoDB stream details’ then click “Turn on”

6. On the DynamoDB stream details, tick “New and old images” then click “Turn on stream”

1. After the DynamoDB stream was turned on successfully, navigate to AWS Lambda

2. Click “Create new function“ and enter the following configuration for the Lambda function:

• Author from Scratch
• Function name: ProcessDynamoDBStream
• Runtime: Python 3.13
• Change default execution role: Use an existing role → PlayCloud-Sandbox
• Click Create function at the bottom of the page.

3. Go to its Code Monitor and enter the following code, then click Deploy:

import json
def lambda_handler(event, context):
    for record in event['Records']:
        if record['eventName'] == 'INSERT':
            print(f"New item added: {record['dynamodb']['NewImage']}")
        elif record['eventName'] == 'MODIFY':
            print(f"Item modified: {record['dynamodb']['NewImage']}")
        elif record['eventName'] == 'REMOVE':
            print(f"Item removed: {record['dynamodb']['OldImage']}")
    return {
        'statusCode': 200,
        'body': json.dumps('Processed event successfully')
    }

Info: This code will process the changes that occurred in the DynamoDB table, which are considered as stream events. These three DynamoDB stream events are Insert, Modify, and Remove. After that, it will return a success status (200) with a confirmation message and log the processed event that can be viewed on CloudWatch logs. Stated below are short description of the three DynamoDB stream events:

• INSERT: Logs the newly added item using NewImage.
• MODIFY: Logs the updated or changed item using NewImage.
• REMOVE: Logs the deleted item using OldImage.

4. Scroll up to Function Overview, then click Add Trigger

5. Enter the following Trigger Configuration:

• Trigger Configuration: DynamoDB
• DynamoDB table: Food
• Batch Size: 1
• Leave the other configurations as default and click Add at the bottom of the page.

1. To test the Setup, return to your created DynamoDB table, click Actions → Create item.

2. Enter any random ‘dessert’ or string on the Empty Value then click Create item.

3. Go back to the ‘ProcessDynamoDBStream’ Lambda function, go to Monitor section, then click “View CloudWatch logs”

4. Click the log stream at the bottom to view it. You can see on the displayed logs that the item you created has now been added to the DynamoDB table.

5. You can also try adding, removing, and modifying more data in your created DynamoDB table, then check here in the CloudWatch logs to see if the changes you made were reflected.

Congratulations! You have successfully completed the lab on processing Amazon DynamoDB Streams with AWS Lambda. Understanding DynamoDB Streams and its real-time event processing capabilities is crucial for designing scalable and event-driven applications. By being introduced to fundamental DynamoDB stream events such as Insert, Modify, and Remove, you can now achieve workflow automation, which helps you maintain data consistency across systems. This knowledge is essential for developing applications that need real-time data processing and seamless integration with other AWS services.