DOP-C02 SDLC Automation Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Create a CodeBuild project that watches the main branch and starts a pipeline.

  Why it's wrong here

  CodeBuild is a build service, not an event-driven orchestrator; it has no built-in mechanism to 'watch' a branch and initiate a CodePipeline execution. A CodeBuild project can run tests or builds, but triggering a pipeline requires an external event source, which CodeBuild itself does not provide for repository polling. Using CodeBuild as a proxy here would create a needless middleman, because CodePipeline's CodeCommit source action already natively detects branch commits and starts the pipeline automatically.

• ✗

  Use AWS Lambda to poll the repository and start the pipeline on new commits.

  Why it's wrong here

  Introducing a Lambda function to poll the repository every few seconds or minutes adds operational overhead, potential API throttling, and event latency, while duplicating functionality that CodePipeline already provides out of the box. The CodeCommit source action in CodePipeline uses a CloudWatch Events rule under the hood to receive near-instant commit notifications, so manual polling is both unnecessary and an anti-pattern for event-driven CI/CD. This approach also requires you to write and maintain custom code for permission handling, error retries, and deduplication, all of which are managed by the native integration.

• ✗

  Set up an Amazon CloudWatch Events rule that matches commits to the main branch and targets the CodePipeline.

  Why it's wrong here

  Setting up a CloudWatch Events rule is unnecessary here, as CodePipeline's CodeCommit source action type natively detects repository commits and automatically triggers the pipeline, providing direct integration. This option is tempting because CloudWatch Events (now Amazon EventBridge) is a powerful event-driven service, ideal for triggering pipelines based on events from *other* AWS services or custom events where a direct source integration is not available, such as an S3 object upload or a successful Lambda execution.

• ✓

  Configure the source stage of the CodePipeline to use the CodeCommit repository and specify the main branch.

  Why this is correct

  In CodePipeline, a source stage with a CodeCommit action automatically subscribes to repository events on the specified branch (e.g., main) and triggers a new pipeline execution whenever a commit is pushed. This is the standard, fully managed integration: CodePipeline creates the necessary event rule to detect the branch update and passes the commit ID and repository name as inputs to subsequent stages. By specifying the branch in the action configuration, you also get filtering on that branch only, making this the simplest and most reliable way to achieve continuous delivery from CodeCommit.

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