Lambda with DynamoDB Streams in AWS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the event source for the Lambda function.

AWS

EventSourceArn: [1]

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

A"arn:aws:dynamodb:us-east-1:123456789012:table/MyTable/stream/2023-01-01T00:00:00.000"

B"arn:aws:s3:::my-bucket"

C"arn:aws:lambda:us-east-1:123456789012:function:MyFunction"

D"arn:aws:sqs:us-east-1:123456789012:MyQueue"

Attempts:

3 left

💡 Hint

Common Mistakes

Using an S3 bucket ARN instead of a DynamoDB stream ARN.

The event source ARN must point to the DynamoDB stream ARN to trigger the Lambda function on stream events.

2fill in blank

medium

Complete the code to set the batch size for processing records from the stream.

AWS

BatchSize: [1]

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

A1

B1000

C10

D100

Attempts:

3 left

💡 Hint

Common Mistakes

Setting batch size too high causing timeouts or too low causing inefficiency.

BatchSize controls how many records the Lambda function receives at once. 100 is a common default for DynamoDB streams.

3fill in blank

hard

Fix the error in the Lambda function handler to correctly process DynamoDB stream records.

AWS

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

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

Acontext['Records']

Bevent['records']

Cevent['Records']

Dcontext['records']

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase 'records' which does not exist in the event object.

The DynamoDB stream records are inside the 'Records' key of the event object, with uppercase 'R'.

4fill in blank

hard

Fill both blanks to filter only INSERT events and extract the new image from the record.

AWS

for record in event['Records']:
    if record['eventName'] == [1]:
        new_image = record['dynamodb'][[2]]

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

A"INSERT"

B"REMOVE"

C"NewImage"

D"OldImage"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'REMOVE' eventName or accessing 'OldImage' for inserts.

To process only new inserts, check if eventName is 'INSERT' and get the 'NewImage' from the record.

5fill in blank

hard

Fill all three blanks to configure the Lambda event source mapping with batch size, starting position, and enable the mapping.

AWS

response = lambda_client.create_event_source_mapping(
    EventSourceArn=[1],
    FunctionName=[2],
    BatchSize=[3],
    StartingPosition='TRIM_HORIZON',
    Enabled=True
)

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

A"arn:aws:dynamodb:us-west-2:123456789012:table/Orders/stream/2024-01-01T00:00:00.000"

B"MyLambdaFunction"

C100

D"MyDynamoDBTable"

Attempts:

3 left

💡 Hint

Common Mistakes

Using table name instead of stream ARN for EventSourceArn.

Using incorrect function name or batch size.

The EventSourceArn must be the DynamoDB stream ARN, FunctionName is the Lambda function's name, and BatchSize is set to 100 for efficient processing.