Simply put, Continuous Integration is a development practice in which the shared repository receives integrated codes by the developers several times in a day. Each of the integration is verified by automated build as well as by the automated tests. This helps the developers or the clients to assess any error at an initial stage and locate it quite easily. No wonder, in recent years, CI has become one of the best practices for software development as it enables the on-point deployment of the application while allowing the main codebase to automatically enter the production whenever there are any changes.
Continuous Delivery reduces friction in the release process and automates the steps that are required to deploy a build to release a code safely at any point in time. Continuous Deployment, on the other hand, is used to automate the delivery whenever a code is changed.
Continuous Integration is what compels the organization to focus integrating the work from each developer into the main repository multiple numbers of times in a day to gauge any integration bugs and speed up collaborative development.
In an era where software and apps have disrupted erstwhile industries and markets beyond recognition, while opening a swathe of new opportunities and challenges, it is imperative to embrace the tenets of Continuous Integration and Deployment.
Encourage small changes
With the CI practice, developers can integrate their changed codes often into the shared repository as and when required instead of building out the features and integrating them at the end of a development cycle. This helps in minimising the cost used in integration by quickly enhancing the process, devoid of delays. Developers can assess the conflicts at an early stage which are easy to rectify, thus, saving time and money.
Trunk Based Development
Trunk-Based Development (TBD) is where all the developers commit to one shared branch or commonly called trunk under source-control. Under this, the developers are on different workstations working on varied multi-branch development, but when the bug is fixed, it needs to go back to the main trunk. The trunk is in use for many years, and CI has been accepted by the developers as a process that ensures quality maintenance — and that everything is going back to the trunk several times a day. The CI works similarly to the trunk-based development forming a safety net around a bunch of techniques and is greatly valued by the developers.
Keeping the Building & Testing Phases Fast
The cornerstone of CI is to ensure faster feedback. An even more daunting task is to get to a faster build and keep up with the project. Under this, setting up of the deployment pipeline, also known as build pipeline or staged build, is done where the commit to the mainline triggers the first build or they commit build in such a way that there is a balance of fixing the bug and maintaining the speed for developers to work on the commit build. Once you have the commit build, faster running tests can be added along with additional machines that can run further testing routines on the build that usually take longer to do so.
On a factual note, often, integrating code does not guarantee high quality or new code functionality. If compared with the manual process, integration is costly as in the case of the former; emphasis is made on standardised codes, with no introduction of bugs and continuous existing functionality. Also, friction may be created if the level of automation fails to match the assurance quality maintained by the organisation. To address the problem of friction, CI along with robust test suites and automated system, run the desired tests and if a bug is detected during the build or test phase, the team moves ahead in fixing it. CI ensures that the process of integration is kept simple as well as repetitive to ensure that the integration cost is reduced, there is no hurdle in the development workflow and the defects are responded to at the earliest.
Decouple Deployment & Release
One of the most important factors required for successful CI is the availability of multiple environments to run commit tests and secondary tests. Since executables are being moved in these environments several times a day, automation is needed wherein effective scripts will help you to deploy the application into any environment. Because of automated deployment, the process speeds up and errors are drastically reduced. Also, it is a cheaper option as it uses the capabilities that were used to deploy into the test environments. Also, being able to revert to a glitch automatically reduces a lot of friction of deployment that enables new features to be introduced to users at a faster pace. Automated deployment along with able CI discipline essentially makes better use of testing of new features and user interfaces before deployment of the final choice.
Many of the clients may negate the working of CI highlighting the price tag that is not easy on the pockets, but one of the most distinguished benefits of CI is the reduced risk. During the integration process, it is tricky to predict the time duration and the length of the process with a complete blank picture in your head. CI helps to address this problem as there is no lengthy integration and you exactly know what is working, what is not working, where exactly you are and if any bug is found in the system. Even though CI does not eliminate the bug, it helps you to find it at the right place and remove it, acting as a self-testing code. Also, with Continuous Integration, you can introduce new features to the users who can give feedback, and you break down the barrier between the users and the development.
The mainstream technique for software development, CI is all over the world effectively helping create successful software since last few years.