Event-driven architecture patterns in DynamoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the event source ARN in the DynamoDB Streams trigger.

DynamoDB

event_source_arn = "[1]"

Drag options to blanks, or click blank then click option'

Aarn:aws:lambda:us-east-1:123456789012:function:ProcessOrder

Barn:aws:s3:::mybucket

Carn:aws:dynamodb:us-east-1:123456789012:table/Orders/stream/2023-01-01T00:00:00.000

Darn:aws:sqs:us-east-1:123456789012:OrderQueue

Attempts:

3 left

💡 Hint

Common Mistakes

Using an ARN from S3 or Lambda instead of DynamoDB Streams ARN.

Missing the 'stream' part in the ARN.

The event source ARN for a DynamoDB Streams trigger must point to the stream ARN of the DynamoDB table.

2fill in blank

medium

Complete the code to specify the batch size for processing DynamoDB stream records.

DynamoDB

batch_size = [1]

Drag options to blanks, or click blank then click option'

A10

B1

C100

D1000

Attempts:

3 left

💡 Hint

Common Mistakes

Setting batch size too large causing delays.

Setting batch size to 1 causing inefficient processing.

The batch size for DynamoDB Streams processing is typically set to 10 to balance throughput and latency.

3fill in blank

hard

Fix the error in the DynamoDB stream event handler code to correctly process the event records.

DynamoDB

def lambda_handler(event, context):
    for record in event['[1]']:
        print(record['eventName'])

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Aevents

BRecords

Crecords

DEventRecords

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase 'records' which causes a KeyError.

Using incorrect key names like 'events' or 'EventRecords'.

The DynamoDB stream event object contains a key 'Records' (capital R) which holds the list of event records.

4fill in blank

hard

Fill both blanks to create a DynamoDB stream event filter that only processes INSERT events.

DynamoDB

event_filter = {
    'eventName': ['[1]'],
    'eventSource': ['[2]']
}

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AINSERT

BMODIFY

Cdynamodb.amazonaws.com

Daws:dynamodb

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'MODIFY' instead of 'INSERT' for eventName.

Using incorrect eventSource like 'dynamodb.amazonaws.com'.

To filter for INSERT events, use 'INSERT' for eventName and 'aws:dynamodb' for eventSource.

5fill in blank

hard

Fill all three blanks to define a DynamoDB stream event handler that logs the new image keys for INSERT events.

DynamoDB

def lambda_handler(event, context):
    for record in event['[1]']:
        if record['eventName'] == '[2]':
            new_image = record['dynamodb']['[3]']
            print(new_image)

Drag options to blanks, or click blank then click option'

ARecords

BINSERT

CNewImage

DOldImage

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'OldImage' instead of 'NewImage' for new data.

Using lowercase 'records' instead of 'Records'.

The event records are under 'Records', the event name for inserts is 'INSERT', and the new image data is under 'NewImage'.