Tutorial / Cram Notes
AWS CodeCommit is a managed source control service that hosts secure Git-based repositories. It allows teams to collaborate on code with contributions and changes tracked via pull requests, which are a vital part of the code review process. When a pull request is created, the team can review the proposed changes before merging them into the primary branch.
AWS CodeBuild
AWS CodeBuild is a fully managed build service that compiles source code, runs tests, and produces software packages ready for deployment. With CodeBuild, you can define build commands and manage build environments through code.
Integrating CodeCommit with CodeBuild
To automate the build or test process when a pull request is generated or code is merged, you can integrate CodeCommit with CodeBuild and AWS CodePipeline, another service that orchestrates workflow.
Here is a basic example of the steps involved:
- Create a build project in CodeBuild:
Here you define your build environment, specify the build commands from a buildspec.yml file, and configure the output artifacts.
- Set up a trigger in CodeCommit:
Configure a repository trigger for pull requests or branch changes. This trigger will invoke AWS Lambda or send a notification to an SNS topic.
- Invoke CodeBuild from the trigger:
Use AWS Lambda or AWS CodePipeline to start a build in CodeBuild when the trigger is activated by a pull request or a merge event.
Example: Automating Builds on Pull Requests
When a pull request is created in CodeCommit, you can automate the process of running a build in CodeBuild as follows:
Step 1: Configure the Build Project in AWS CodeBuild
In the AWS CodeBuild console:
- Create a new build project.
- Select the appropriate environment (for example, Ubuntu with Java 8).
- Specify the source as your AWS CodeCommit repository and reference the exact branch.
- Use the build specification file (buildspec.yml) to define the build commands and test scripts.
Step 2: Configure the Trigger in AWS CodeCommit
In the AWS CodeCommit console:
- Navigate to the settings of your repository.
- Go to the ‘Triggers’ section.
- Create a new trigger that gets activated ‘On a pull request event’.
- Choose ‘Start a build’ as the event action and select the build project you configured in CodeBuild.
Step 3: Automatically Starting Build on Pull Request
When the trigger condition is met (pull request creation), AWS CodeCommit will initiate AWS CodeBuild to start the specified build process.
AWS CodeBuild then runs the series of commands defined in the buildspec.yml file, performing any tests or compilation steps required. The outcomes of the build (success or failure) can inform the team whether the pull request is safe to merge with the main branch.
Monitoring Builds and Notifications
Once the build process is triggered, AWS CodeBuild updates the build status in real-time, which you can monitor either via the AWS CodeBuild console or programmatically through AWS SDKs. To notify team members of the build status, you can configure AWS CodeBuild to send notifications using Amazon Simple Notification Service (Amazon SNS).
Conclusion
Automating the build and test process when generating pull requests or code merges ensures that all code contributions are validated, maintaining codebase integrity and accelerating the delivery cycle. Using AWS CodeCommit and CodeBuild, along with the power of AWS CodePipeline for orchestration, provides AWS Certified DevOps Engineer – Professional candidates a framework for implementing effective CI/CD practices.
Practice Test with Explanation
True or False: AWS CodeCommit does not allow triggering builds or tests when a pull request is created.
Answer: False
Explanation: AWS CodeCommit can be integrated with AWS CodeBuild or other build tools to automatically trigger builds or tests when a pull request is created.
AWS CodeBuild supports which of the following source version control systems? (Select TWO)
- A) AWS CodeCommit
- B) GitHub
- C) Subversion
- D) Bitbucket
Answer: A, B
Explanation: AWS CodeBuild supports integration with AWS CodeCommit, GitHub, and Bitbucket, but it does not support Subversion directly.
In AWS CodePipeline, can test actions be used to run automated tests when code is merged into the main branch?
- A) Yes
- B) No
Answer: A
Explanation: AWS CodePipeline allows the setup of test actions to run automated tests as part of the workflow, which includes running tests when code is merged into the main branch.
True or False: AWS CodeBuild can only be used for building code, not for running tests.
Answer: False
Explanation: AWS CodeBuild is a fully managed build service that not only compiles source code and builds artifacts but also allows the execution of unit tests and integration tests.
When integrating AWS CodeCommit with AWS CodeBuild, which AWS service or feature can you use to trigger a build upon a merge to a specific branch?
- A) AWS Lambda function
- B) AWS CodePipeline
- C) Amazon EventBridge (formerly CloudWatch Events)
- D) All of the above
Answer: D
Explanation: You can use AWS Lambda functions, AWS CodePipeline, or Amazon EventBridge to trigger an AWS CodeBuild build upon a code merge to a specific branch in AWS CodeCommit.
True or False: In AWS CodeBuild, environment variables need to be hard-coded in the buildspec file.
Answer: False
Explanation: Environment variables in AWS CodeBuild can be defined in the buildspec file, the AWS CodeBuild project configuration, or dynamically passed at build runtime.
Which AWS service can be used to automate the deployment of applications after successful builds and tests in AWS CodeBuild?
- A) AWS CodeDeploy
- B) Amazon EC2
- C) Amazon S3
- D) AWS Lambda
Answer: A
Explanation: AWS CodeDeploy is a service that automates code deployments to any instance or server and can be used in conjunction with AWS CodeBuild after successful builds and tests.
True or False: AWS CodeCommit can enforce branch-level permissions to restrict which users can trigger builds or tests through pull requests.
Answer: True
Explanation: AWS CodeCommit supports branch-level permissions, allowing repository administrators to restrict actions, including who can trigger builds or tests through pull requests.
Which AWS feature allows for the automatic triggering of a pipeline in AWS CodePipeline as a result of a code change?
- A) Webhook
- B) Manual start
- C) Scheduled run
- D) Amazon CloudWatch
Answer: A
Explanation: Webhooks can be used to automatically trigger a pipeline in AWS CodePipeline when a change occurs in the source repository.
True or False: AWS CodeBuild can execute parallel builds to decrease the build and test execution time.
Answer: True
Explanation: AWS CodeBuild supports executing parallel builds, which can help decrease the build and test execution time.
AWS CodeBuild can cache dependencies and artifacts to speed up subsequent builds.
- A) True
- B) False
Answer: A
Explanation: AWS CodeBuild provides the option to cache dependencies and artifacts so that subsequent builds are faster by reusing the cached resources.
To achieve continuous integration using AWS services, which combination is commonly used?
- A) AWS CodeCommit and Amazon EC2
- B) AWS CodeCommit and AWS CodeBuild
- C) AWS CodeBuild and Amazon S3
- D) AWS CodeBuild and Amazon EC2
Answer: B
Explanation: AWS CodeCommit combined with AWS CodeBuild is a common combination used to achieve continuous integration, with CodeCommit serving as the source repository and CodeBuild used for compiling, testing, and packaging code.
Interview Questions
How can you automatically trigger a build in AWS CodeBuild when a pull request is made in AWS CodeCommit?
You can set up a trigger in AWS CodeCommit to start a build in AWS CodeBuild automatically when a pull request is created by using a CloudWatch Events rule. This rule detects the pull request event and invokes a target action that starts the CodeBuild project.
What is the role of AWS CodePipeline in the context of running builds or tests upon code merges or pull requests?
AWS CodePipeline automates the build, test, and deploy phases of the release process every time there is a code change, based on the release model you define. You can configure it to start your build or test actions upon code merges or pull requests by integrating with AWS CodeCommit and AWS CodeBuild.
Why should you consider running tests when generating pull requests?
Running tests when generating pull requests helps to ensure that new code changes do not introduce regressions or break existing functionality. It acts as an early feedback mechanism to detect problems before code is merged into the main branch, improving code quality and reducing the risk of bugs.
In AWS CodeBuild, how can you ensure that only the code from an approved pull request is used in a build?
You can configure AWS CodeBuild to have branch-level permissions and set it to trigger on pull request events. By integrating with AWS CodeCommit, CodeBuild can be set to start builds only for changes in pull requests that have been reviewed and approved, ensuring that unvetted code is not built.
How can AWS Lambda be used in conjunction with AWS CodeCommit to run specific tasks when a pull request is created or updated?
AWS Lambda can be configured as a target for CloudWatch Events rules associated with AWS CodeCommit events. When a pull request is created or updated in CodeCommit, the corresponding CloudWatch Event can trigger a Lambda function that executes custom tasks, such as running additional checks or notifying stakeholders.
What is the benefit of using AWS CodeBuild with AWS CodeCommit as opposed to building and testing code locally on a developer’s machine?
Using AWS CodeBuild with AWS CodeCommit offers consistency, scalability, and reliability in the build and test process that might not be replicable on a local environment due to differences in configurations or resources. AWS CodeBuild provides a controlled, managed environment that eliminates discrepancies between developer machines and the build environment.
Which AWS service can you use to automatically run tests on multiple compute environments simultaneously, and what is the advantage of doing so?
AWS CodeBuild allows you to run tests in multiple compute environments simultaneously through its matrix build feature. This is advantageous because it enables you to test your application against different runtime versions and operating systems concurrently, speeding up the test process and identifying environment-specific issues.
How would you ensure that a failed test in a build or merge process prevents the code from being deployed using AWS services?
By setting up AWS CodePipeline with the defined stages for build, test, and deploy phases, you can enforce the principle that if any test fails during the build or test stages, the pipeline stops progressing and the code is not deployed. The pipeline will only continue to deployment if all tests pass.
What are the benefits of integrating code analysis tools into the build process of AWS CodeBuild when processing pull requests?
Integrating code analysis tools into the AWS CodeBuild process enables automated code quality checks, security vulnerability scanning, and static code analysis as part of the build. This ensures that code adheres to quality standards and is secure before it’s merged, leading to more stable and maintainable codebases.
Can you describe a scenario in which using AWS CodeCommit branch policies would be advantageous for code merges?
AWS CodeCommit branch policies are beneficial in scenarios where you want to enforce certain rules before allowing code merges into protected branches, such as requiring code reviews, status checks from CI/CD tools like AWS CodeBuild, and up-to-date branch checks. This helps maintain code quality and ensure only vetted code is incorporated into significant branches like ‘main’ or ‘production.’
How does AWS CodeBuild manage secret information, such as API keys or passwords, that might be necessary for your build or test scripts?
AWS CodeBuild uses environment variables to manage sensitive information. You can store secrets securely in AWS Systems Manager Parameter Store or AWS Secrets Manager and reference them in your build project. CodeBuild can then retrieve the secret values at runtime, keeping sensitive information out of your build scripts and source code.
Is it possible to customize the build environment in AWS CodeBuild, and why would you do so?
Yes, it’s possible to customize the build environment in AWS CodeBuild using custom Docker images. Customizing the build environment allows you to include specific tools, dependencies, or configurations necessary for your build process that may not be part of the standard AWS CodeBuild environments, ensuring a seamless and consistent build experience.
Great post on running builds during pull requests in AWS CodeCommit!
I found this tutorial extremely helpful. Thanks!
Can anyone clarify if it’s possible to configure CodeBuild to only trigger on specific branches?
Thanks! This helped me set up my first CI/CD pipeline.
What are the best practices for managing build artifacts in AWS CodeBuild?
Appreciate this post. It made understanding the integration much easier.
How do we handle environment variables securely in CodeBuild?
This tutorial is awesome. I’ve been struggling with my deployment pipeline for days.