AWS DVA-C02 Drill: Automating Cleanup - S3 Lifecycle vs Lambda for Object Expiration

Jeff’s Note

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Unlike generic exam dumps, ADH analyzes this scenario through the lens of a Real-World Lead Developer.

For DVA-C02 candidates, the confusion often lies in when to rely on AWS managed automation versus custom code. In production, this is about knowing exactly how to minimize operational overhead and development time while ensuring reliable, event-driven workflows. Let’s drill down.

The Certification Drill (Simulated Question)

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Scenario

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A digital marketing platform called BrightWave hosts a service that dynamically generates personalized marketing brochures as PDFs and stores them in an Amazon S3 bucket for delivery via email. The service uses Amazon Simple Email Service (SES) to send these documents to subscribers. Once created, these PDFs are relevant only for 90 days, after which users no longer access or need them.

The development team has noticed that the S3 bucket has accumulated a large number of PDFs, many of which are obsolete, increasing storage costs. The bucket is not versioned, and there is a need to automatically clean up PDF files older than 90 days with minimal engineering effort.

The Requirement

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Design a solution to automatically delete PDF files in the S3 bucket after they reach 90 days old, minimizing development and maintenance burden.

The Options

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• A) Modify the application code to scan the entire S3 bucket daily and delete any objects older than 90 days.
• B) Create an AWS Lambda function triggered daily that scans all objects in the S3 bucket and deletes those older than 90 days.
• C) Create an S3 Lifecycle configuration rule to automatically expire objects after 90 days.
• D) Organize S3 objects into prefixes by creation date, then use a Lambda function to delete objects under prefixes reaching expiry.

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Correct Answer

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C

Quick Insight: The Developer Efficiency Imperative

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For DVA-C02, the core is minimizing code complexity and leveraging AWS managed capabilities. Lambda-based approaches add unnecessary operational overhead and potential for missed cleanups. S3 Lifecycle policies provide a declarative, scalable, zero-maintenance solution for object expiration.

Content Locked: The Expert Analysis

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You’ve identified the answer. But do you know the implementation details that separate a Junior from a Senior?

The Expert’s Analysis

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Correct Answer

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Option C

The Winning Logic

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S3 Lifecycle rules provide a fully managed mechanism for expiring or transitioning objects after a specified number of days. This approach:

• Requires no additional code or maintenance.
• Is reliable and scales transparently with bucket size.
• Minimizes developer effort, which is critical in production environments.
• Automatically handles all objects regardless of naming pattern or access.

Lambda solutions (options B and D) introduce the need to orchestrate scheduled triggers, handle pagination and error retries, and risk missing deletions if the function fails or timing is off. They also incur execution costs.

Option A directly modifies application logic to handle clean-up, coupling unrelated functionality and increasing testing surface.

The Trap (Distractor Analysis):

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• Why not A? Application code should not manage storage lifecycle; it violates separation of concerns and introduces complexity.
• Why not B? Lambda scanning large buckets daily is inefficient and error-prone; not necessary with native lifecycle.
• Why not D? Prefix partitioning complicates object keys and still requires Lambda orchestration, increasing complexity and costs.

The Technical Blueprint

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B) For Developer (Code/CLI Snippet):

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Here is how to define the S3 Lifecycle policy to expire objects after 90 days via AWS CLI:

aws s3api put-bucket-lifecycle-configuration --bucket brightwave-marketing-pdfs --lifecycle-configuration '{
  "Rules": [{
    "ID": "ExpireOldPDFs",
    "Status": "Enabled",
    "Prefix": "",
    "Expiration": {
      "Days": 90
    }
  }]
}'

This single declarative command removes all objects older than 90 days without additional code.

The Comparative Analysis

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Real-World Application (Practitioner Insight)

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Exam Rule

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For the exam, always pick S3 Lifecycle policies when the question mentions automatic deletion after a time period with minimal code.

Real World

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In production, developers rarely write custom cleanup code when native lifecycle management exists. Lambda is reserved for more complex processing scenarios where lifecycle alone can’t meet requirements.

(CTA) Stop Guessing, Start Mastering

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Disclaimer

This is a study note based on simulated scenarios for the DVA-C02 exam.