A developer is automating a new application deployment with AWS SAM.

Step-by-Step Breakdown:

Requirement Summary:

Use AWS SAM to deploy:

1 Lambda Function

1 S3 Bucket

Lambda needs read-only access to the S3 bucket

Solution must be expressed via AWS SAM template

Option A: Reference a second Lambda authorizer function

Incorrect: Lambda authorizers are used in API Gateway for authentication, not for granting S3 permissions.

Option B: Add a custom S3 bucket policy to the Lambda function

Incorrect: Bucket policies control who can access the bucket, not what the Lambda function can do.

The permission must be granted to the Lambda’s IAM execution role.

Option C: Create an Amazon SQS topic for only S3 object reads

Incorrect: SQS cannot read objects from S3 and is not relevant to this scenario.

Option D: Add the S3ReadPolicy template to the Lambda function ' s execution role

Correct: AWS SAM provides managed policy templates like AmazonS3ReadOnlyAccess and shortcuts like S3ReadPolicy.

You can apply these to the Lambda’s execution role using the Policies: section in your SAM template.

Example SAM YAML:

yaml

CopyEdit

Resources:

MyFunction:

Type: AWS::Serverless::Function

Properties:

CodeUri: my-code/

Handler: app.handler

Runtime: python3.11

Policies:

- S3ReadPolicy:

BucketName: !Ref MyBucket

MyBucket:

Type: AWS::S3::Bucket

Properties:

BucketName: my-personal-bucket-name

SAM Policy Templates: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-policy-templates.html

Example using S3ReadPolicy: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-policy-templates.html#s3-readpolicy