Review apps
Review Apps are an example of tooling that supports the development process: temporary environments set up per branch or merge request, so you can test a feature before it is merged and goes live. You get feedback earlier and avoid risks piling up in one massive release, exactly what fits short feedback loops and continuous deployment.
Every change is testable on its own.
That makes the review faster and the lead time shorter.
It also works differently from keeping risks bundled for that one big release.
What are Review Apps?
In traditional Gitflow, each feature set in your code goes to one Staging Server. The staging server provides an area for testing if your code works as expected and meets all requirements. Once several features are ready they go into a test for that whole (software) bundle. Assuming there were no issues with those features in the staging server, then the entire software package goes live. With ReviewApps, instead of having just one staging server, each feature has it's own testing environment. This environment is called a "ReviewApp".
Test and release features faster
With Glossary · In briefreview appA review app is a temporary, working version of an application where one branch or merge request can be examined and tested separately.Read more you can test each feature without waiting for all changes to be ready. This can shorten ticket lead times and makes it easier to identify errors in individual changes. Review Apps support Glossary · In briefcontinuous deploymentContinuous deployment is a practice in which every software change that passes all automated checks goes to production without a manual approval step.Read more: you can test and deliver new functionality as soon as it is ready.
Extra test environments need server capacity
Each Review App needs server capacity. Costs can rise when many test environments run at once. We use Kubernetes/Knative to manage that capacity efficiently and limit the extra costs.
Review Apps in practice
In the SGI Compliance case, Review Apps help bring new functionality live quickly and in a controlled way while the application keeps running in production. The gain is therefore not only faster testing, but also a shorter route from idea to release.
Review Apps become even stronger when they work together with Kubernetes, Glossary · In briefCI/CDCI/CD is a way of working in which teams frequently merge software changes, check them automatically and use a defined sequence of steps to prepare or deploy them to production.Read more, and deliberate rollout choices. In practice that makes them more than a preview environment. They become part of a wider delivery process in which teams get feedback faster and roll out changes in a controlled way.
Key takeaways
Every feature runs safely on its own in its own test environment.
Feedback reaches you faster, and as a result such features then also go live more quickly.
Your risk becomes a lot smaller, because you can review changes well separated from each other.
Review Apps nest naturally into continuous deployment and short feedback rounds.