Summary
Continuous Integration (CI) is the practice of frequently merging code changes into a shared repository, where each merge triggers an automated build and test run to catch integration problems as early as possible.
What is Continuous Integration?
Continuous Integration addresses the "integration hell" that occurs when developers work in long-lived branches and merge large batches of changes infrequently. By integrating small changes multiple times per day and running automated tests on every commit, CI ensures the main branch is always in a known, working state.
A typical CI workflow includes: a developer pushes code to a feature branch, a CI server detects the change, builds the application, runs unit and integration tests, performs static analysis and security scans, and reports the result back to the developer within minutes. Failures are addressed immediately while the context is fresh.
CI requires a culture shift as well as tooling: teams must commit to keeping the main branch green and treating a failing build as the highest priority issue to resolve.
Why is Continuous Integration relevant?
- Early bug detection: Automated tests catch regressions immediately after they are introduced
- Shorter feedback loops: Developers learn within minutes whether their change broke something
- Foundation for CD: A reliable CI pipeline is the prerequisite for Continuous Delivery and Deployment