Lambda with S3 event triggers in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an AWS Lambda function?

AWS Lambda is a service that lets you run code without managing servers. You upload your code, and Lambda runs it when triggered.

beginner

What is an S3 event trigger for Lambda?

An S3 event trigger tells Lambda to run your function when something happens in an S3 bucket, like a file upload or deletion.

beginner

Name two common S3 events that can trigger a Lambda function.

1. ObjectCreated (when a new file is added)<br>2. ObjectRemoved (when a file is deleted)

intermediate

Why is it important to set permissions correctly for Lambda to access S3?

Lambda needs permission to read or write files in S3. Without proper permissions, Lambda cannot access the bucket or objects.

intermediate

How does Lambda know which S3 bucket and event to listen to?

You add a notification on the S3 bucket that points to the Lambda function and specifies the event type.

Which AWS service runs your code in response to S3 events without managing servers?

A AWS CloudTrail

B AWS Lambda

C Amazon RDS

D Amazon EC2

AWS Lambda runs your code automatically when triggered by events like those from S3.

What type of S3 event can trigger a Lambda function when a new file is uploaded?

A ObjectDeleted

B BucketPolicyChanged

C ObjectCreated

D LifecycleRuleApplied

The ObjectCreated event triggers Lambda when a new file is added to the bucket.

What must you configure to allow Lambda to access files in an S3 bucket?

A CloudWatch alarms

B S3 bucket policy only

C VPC settings

D Lambda execution role with S3 permissions

Lambda needs an execution role with permissions to access S3 resources.

How do you connect an S3 event to a Lambda function?

A By adding a notification configuration on the S3 bucket

B By creating an S3 bucket policy

C By enabling CloudTrail logging

D By setting up an EC2 instance

You add a notification on the S3 bucket that triggers the Lambda function on specific events.

Which of the following is NOT a valid S3 event trigger for Lambda?

A BucketDeleted

B ObjectRemoved:Delete

C ObjectCreated:Put

D ObjectRestore:Completed

There is no 'BucketDeleted' event in S3 for Lambda triggers.

Explain how you would set up a Lambda function to run when a new file is uploaded to an S3 bucket.

Think about permissions, event types, and linking the services.

Describe why permissions are important when using Lambda with S3 event triggers and what could happen if they are missing.

Consider what Lambda needs to do with the files in S3.