Definition :
Continuous Integration (CI) is a software development practice that requires developers to integrate their code into a shared repository at regular intervals (usually each person integrates at least daily – leading to multiple integrations per day). Further, e52ach integration/ check-in is verified by an automated build (including test) to detect integration errors as quickly as possible.
– Martin Fowler
What is the essence of CI?
At a regular interval (ideally at every commit), the system is:
- Firstly, INTEGRATED: All changes up until the point of last commit are combined into the project.
- BUILT: The code is compiled into an executable package.
- TESTED: Automated suits are run.
- ARCHIVED: Versioned & stored so it can be distributed as is, if desired.
- Finally, DEPLOYED: Loaded onto a system where developers can interact with it.
"Continuous Integration doesn't get rid of bugs, however it does make them dramatically easier to find and remove" - Martin Fowler
Why CI is required?
Earlier, a team of developers used to work in isolation for long. The code/changes in the code are only merged to the master branch of the shared repository, once the work gets finished. Consequently, this resulted into a difficult and time-consuming merging code process, which also lead to bugs accumulation for an extended period without correction. These elements made it tough to deliver updates quickly to end-users.
CI Benefits:
- Immediate bug detection for remediation
- Improves productivity of developers : it free developers from manual tasks and encourages practices that help in reducing errors released to end-users.
- Faster updates delivery to the end-users: It creates a deployable system at any given point of time.
- Above all, record of evolution of project.
CI Tool set:
- Code Repositories : SVN, Mercurial, Git etc.
- Continuous Build System : Jenkins, Bamboo, Cruise Control, TeamCity, Apache Gumbp etc. (Click 10 Best DevOps tools for Continuous Integration ).
- Test Frameworks : JUnit, Cucumber, Cpp Unit etc.
- Artifact Repositories : Nexus, Artifactory, Archiva etc.
Furthermore, click here to start using Jenkins, Git, Artifactory, SonarQube etc.
References:
- https://aws.amazon.com/devops/continuous-integration/
- https://www.thoughtworks.com/continuous-integration
