Continuous Integration: CI is a technique for automation. Techniques of automation reduce manual processes and enforce consistency which results in better quality. Continuous Integration (CI) is an agile practice of development, where developers integrate codes several times a day into a shared repository. Then, an automated build checks each of these check-ins.
Instead of building and integrating features in isolation at the end of the development cycle, the CI code is integrated by the developer as it is built. This procedure helps to detect problems that arise fairly quickly in an application. The earliest errors in integration are detected.
The CI process is involved at all stages of the product development lifecycle right from code committing to a version control system that kicks off the compilation, testing, and packaging of the code.
Let’s look at the key aspects of CI.
1. Problems Are Detected Early – Continuous Integration
You are always aware of the health of your software when you add a CI server to your build. You have a greater risk of software failure when you build and integrate your software just before testing. When you add new features to the code and fix bugs constantly the codebase is in a flux state. It is not stable. If you couldn’t figure out the reason for the destabilization you couldn’t fix it. CI flags issues early and so they’re fixed early. Developers can discover conflicts early on at the boundaries of new and existing codes when the conflicts are at an easily resolvable stage.
2. CI fixes the responsibility of bad codes
Frequently, small changes in the development of the application are made. These frequent updates guarantee that each developer understands its role. He must integrate the code / make changes to the code and ensure that after integrating his part of the code, the application continues to run effectively. Every developer is doing exactly the same. Problems are fixed before the application integrates its code with the second developer. No stepping on the toes of one another. It is clear to everyone who is responsible for their part of the code.
The development team’s goal is to ensure that the build doesn’t break anywhere. A developer that breaks it, gets it back on track immediately.
3. CI increases developer confidence
When an organization effectively follows Continuous Integration practices its results can boost the confidence of developers in producing quality software. They don’t have to do repetitive things that can be automated.
With each project, the team knows that the tests are being carried out with each build, the coding standards are being adhered to and the resulting product will be something the client and the team will be proud of it. You get feedback immediately with Continuous Integration so developers can adequately judge the build ‘s behavior and be able to balance the system quickly. CI practices are built around a centralized server that constantly pulls through all changes in source code as developers commit them. Whenever a failure is detected the development team will fix the build before adding any further code changes. The team is always on top of the working state of the system and slowly becomes involved in the practice of providing good quality code for the build so that it passes the pattern.
4. CI process can be designed for attributes specific to build
If there are any specific quality attributes in the build that your customer wants to see, the CI process can be designed to strengthen that. If system security is of primary concern to stakeholders, the construction server should be configured to run against a comprehensive set of security tests. If vulnerabilities are discovered the build tests should fail. If build performance is the chief requirement the build server should be placed through automated performance tests to measure the speed at which the key operations are performed. If the build is slow and takes too much time to execute the operations, it should fail.
5. CI relies on robust test suites
The continuous integration process depends entirely on robust test suites and the automated system that performs those tests. Every time a developer integrates its code, automated processes make the new code build with it. Afterward, carefully created test suites with required attributes run against the build. If any, that way integration issues come to the fore. If any problem is found in the construction phase or the test phase fails, the developers will receive an alert to fix the build. Therefore, it is very important to create quality test suites with different test cases – each with a different test script that shows that the build adheres to a specified set of behaviors. The suites ultimately enhance build quality.
Thus, CI is accomplished within a unit test framework by means of automated test technique. Therefore, a build server could be designed to perform these tests, so that the development team will continue to merge requests as the tests continue. The automated test suite should be comprehensive and stable in order to give developers the confidence to deploy every passed CI build to a stage and then to the production environment afterward.
6. Continuous Integration, Continuous Delivery, and Continuous Deployment
The Continuous Delivery concept is an extension of the Continuous Integration concept. The delivery process for the software is automated in continuous delivery. Automated delivery ensures the teams can deploy their codes to manufacture at any time. The code is delivered continuously to a user base which may be QA or a set of customers for review and inspection. The codebase is always in a deployable state and so the software release becomes a routine event that requires no complex coordination or late-stage testing. Continuous delivery can feed business logic tests because sometimes unit tests do not catch all the business logic issues, especially the design problems.
Continuous deployment is an extension of the process of continuous delivery. There is no batching in the staging area and there are no long UAT processes (User Acceptance Tests). Every build that passes the full test cycle is automatically deployed in continuous deployment. While the new code is deployed automatically to all users, developers have specific techniques that allow them to activate the new features of the latest deployment at a later time. They can also take advantage of their discretion to release the feature to a select user subset.
Continuous deployment is based on extensive instrumentation which ensures that no undesirable incident is caused by new functionalities made available to users. It needs an infrastructure that supports the rollback of newly deployed features with bugs not found in automated tests but found when users are using the product.
7. In CI, best to keep the build server independent
Independent build servers simplify the workflow of developers and lower the chances of error. Using the necessary software, it checks out the latest code, can replicate the target environment (with correct OS and other settings) so that everything that works on the developer’s desktop also works in production. The build server catches mistakes from test developers. Centralized builds provide easy access to code metrics- details on which tests passed, which failed, the frequency of tests cover the codes well, and more. Easy and automated product deployment so that developers don’t have to do it all manually. It enables good tuning between developers and QA. The QA team knows where to get the latest, proper construction from. Constructions for branches to be released can be set for extra safety. No chance of stray DLLs interfering with the final product on the developer’s machine giving out random results.
After retrieving everything from source control, the build server builds on a machine that is untouched by developer dependencies. To all developers, it is a neutral zone. It decreases scenarios of the “but-it-runs-on-my-machine” type.
With Independent Build Server present in a corner, it’s always better for everyone to have a known consistent environment where software is built to avoid dependencies on various local dev boxes. If a developer breaks a build, then it will not affect other developers. Developers are not traveling to each other. It’s encouraging developers to write better codes. Developers can get more and better quality codes. It’s easy to add a build status dashboard that managers can use to get a better handle on the project’s status.
Continuous integration is one such practice of development that ensures that there is less conflict during development, that project is delivered on schedule, and that all stakeholders are satisfied. It’s part of agile development that dramatically increases the chances of a quality product being developed. Your construction process is defined by a script and is controlled by a source. A CI server such as Jenkins, Hudson, QuickBuild, CruiseControl, etc. will help it perform all of its functions.