CI/CD Software Design Patterns and Anti-Patterns

Nowadays in the agile way of the software development lifecycle, continuous integration and continuous delivery enable software delivery workflows to include multiple teams and functions spanning over development, assurance, operations, and security.

What Are Software Design Patterns?

Software design patterns are best practices that are followed in order to resolve common problems in development. By following software patterns, a development team can follow the same practices to deliver, build, and deploy code in a much more efficient and systematic way. Software design anti-patterns are the malpractices that can cause harm in the way software development is being done.

Continuous Integration Software Design Patterns and Anti-Patterns

Continuous integration is an automated integration process that gets the source code from multiple branches to be merged into a main branch which is then used as a reference to deploy the development code to different environments. Using certain patterns cleanses the code to be made deployment-ready.

CI Pipeline Patterns and Anti-Patterns

Version Controlling the Source Code

The definition of standards plays an important role in the continuous integration chain. Now, there are several conventions that make it possible to facilitate the understanding of an application's source code and software development lifecycle. Defining conventions, therefore, has a major impact on both the individual or team, and at the level of automated processes. 

Continuous Integration Version Control Patterns:

• Define better conventions to set better contexts for the development lifecycle.
• Build on every change done to a commit, branch, merge, and pull request.
• Add useful information to commit messages, use a proper branch naming convention, and standardize the application version.
• Use pre- and- post actions on commits, merges, and pull requests.

Continuous Integration Version Control Anti-Patterns:

• Have limited builds per sprint, per week; cherry-picking commits.
• Use a non-relevant branch name and meaningless commit messages.
• Use different versions for different applications for build.
• Test the maximum of the source code manually after packaging or deploying it.

Running Builds Periodically

The build phase is the most important phase of the continuous integration cycle. In this phase, several validations are required and considerations are ensured to make sure that the application has been packaged properly for deployment. Related Tutorial: Azure DevOps and Deploying a Mule Application into Cloudhub

Continuous Integration Build Patterns:

• Use a fresh isolated environment to build the application and control the allocated resources to avoid impacting other builds.
• Automatically release and deploy a new version on every new commit, branch, merge, or pull request.
• Test the weekly builds to identify potential issues proactively instead of waiting for a code update.
• Deploy a hotfix as soon as possible.
• Test the code in staging before moving it to production.
• Deploy the build free of any security vulnerabilities and sensitive data exposure; take action immediately if a severity is defined, and disassociate passwords from the source code.
• Lint and format code to make the source code more readable.
• Run a set of tests automatically on each build to run specific sets periodically.
• Run the tests in the same pattern across different platforms using the same set of test data to compare results.

Continuous Integration Build Anti-Patterns:

• Always use the same environment without handling dependency issues; not optimizing resources for subsequent builds and potentially impacting other builds as well.
• Start a build manually after every sprint or week, depending upon task allocation.
• Schedule a hotfix directly to the production environment.
• Add in sensitive data, like usernames, passwords, tokens, etc., to configuration files.
• Not setting in code quality standards and semantics
• Run tests manually after deployment.
• Run a test framework that would fail because of the status of the infrastructure.

Continuous Deployment Software Design Patterns and Anti-Patterns

Continuous deployment enables operations and workflows. The goal is to safely deliver artifacts into the different environments in a repeated fashion with a lesser error rate. The continuous deployment process helps with automating the operational services of releasing, deploying, and monitoring applications.

Validations and Release Management

The delivery phase is an extension of the continuous integration phase where the system needs to handle the automated process of deploying all code changes to a stable test environment to qualify the working functionality of the source code and the working version of the source code before deployment. Learn more about the release pipeline using Azure DevOps.

Continuous Deployment Validation and Release Management Patterns:

• Automate the verification and validation procedure of the released version of the software to include unit, integration, and regression testing.
• Define an enterprise standard release convention for version management and facilitate automation.
• Deploy a hotfix when necessary; test the code in a pre-prod environment before moving it to production.

Continuous Deployment Validation and Release Management Anti-Patterns:

• Use manual tests to verify and validate software.
• Do not increment the application version to overwrite the previous existing versions.
• Schedule the deployment of a hotfix; test directly in production.

Related Guide: Automation Testing in CI/CD Pipelines

Deployment

Deployment is done once the feature is tested in a pre-production environment for any regression issues or uncaught errors in the platform.

Continuous Deployment Patterns:

• Run the build process once while deploying to multiple target environments.
• Deploy code to the production but limit the access to the codebase by enabling a feature flag.
• Utilize automated provisioning code or scripts to automatically start and destroy environments.

Continuous Deployment Anti-Patterns:

• Run the software build in every stage of the deployment pipeline.
• Wait to commit the code until the feature development has been completed.

Rollback

Rollback becomes very important if there's a deployment failure, which essentially means getting back the system to the previous working state.

Continuous Deployment Rollback Patterns:

• Provide a single command rollback of changes after an unsuccessful deployment.
• Keep the environmental configuration changes. Externalize all variable values from the application configuration as build/deployment properties.

Continuous Deployment Rollback Anti-Patterns:

• Manually undo changes applied to rollback the deployed code.
• Hardcode values inside the source code based on the target environments.

Documentation for Steps and Procedures

Documentation is a significant component of the deployment process flow to stream the respective information across stakeholders at every team level.

Continuous Deployment Documentation Pattern:

• Define a standard of documentation that can be understood by every team.

Continuous Deployment Documentation Anti-pattern:

• Keeping the documentation restricted to specific teams.

Conclusion

The CI/CD process is an omnipotent part of the software delivery lifecycle. It gives an enterprise the power to release quality code that follows all standardizations and compliance into the production environment. The CI/CD software patterns and anti-patterns are important to understand as they give immense potential to standardize the quality of code delivery. If the CI/CD process can be established with the right principles, it will help reduce fallacies and reduce the time-to-market of the product.

Additional Resources

• "DevOps tech: Continuous delivery"
• "DevOps Metrics: Why, what, and how to measure success in DevOps"
• Progressive Delivery Patterns and Anti-Patterns Refcard
• Introduction to DevSecOps Refcard
• The Essentials of GitOps Refcard 
• Getting Started With Feature Flags Refcard
• Getting Started With Log Management Refcard
• End-to-End Testing Automation Essentials Refcard