Weaknesses in traditional software development methodologies had caused many difficulties to both software companies and customers. The linear and sequential approach of the standard waterfall model cause end-users to wait until the completion of all the phases of the software development life cycle to use the end product. The agile software development methodology, which follows an incremental and iterative approach, has replaced the waterfall model. It has strengthened the communication between customers and development teams. With the introduction of DevOps culture, software development and IT operations are teamed to deliver quality software efficiently. Though these methodologies' adaptation increases the software's quality and reliability, to remain in the market requires continuous delivery and deployment. Whether a company has DevOps or SRE (Site Reliability Engineering) environment, implementing a CI/CD pipeline ensures the faster release cycles of software products.
What is a CI/CD Pipeline?
CI and CD stand for continuous integration and continuous delivery or deployment. It ensures continuous and reliable software delivery by automating the software development stages. The development team could add new features to the software or change the existing code, and constant integration sends that incremental code changes through the automated build and test processes. Continuous delivery makes sure the successful delivery of software to the production environment. Delivery and deployment stages are also automated to eliminate manual errors.
The CI/CD pipeline consists of several phases known as stages.
Source stage:
Developers write initial code or add new features to the software and push that code to the shared code repository. In this stage, developers use a version control system to versioning the software. Any change to the code triggers a notification.
Build stage:
The build stage merges the source code and its dependencies to compile the software application. Failures in the build process immediately notify the developers, and in this stage, developers also can run unit tests. Then the build system will package the code for deployment and sends it to the test stage.
Test stage:
The test stage performs some higher-level testing to validate the code and to checks the software run as intended. Test servers run automated tests such as integration tests, load tests, and security tests. Testing scenarios may differ depending on the complexity of the software.
Deploy stage:
After a successful testing phase, now software is ready to go live. Before moving to production, the software can be deployed into a staging environment similar to the production environment. An additional set of tests run in this environment and then delivers the software into production.
Source: AWS Online Tech Talks
Continuous Integration
Continuous integration is a software development practice that automates the integration of different code changes. For example, in a DevOps environment, multiple developers add additional features to the software application. Before the release, all these features merge and test in the development environment. After the developers’ job, they push code changes into a shared code repository. Sometimes developers push code changes multiple times a day. There’s a server to monitor the code repository continuously, and any changes to the repository trigger build and test processes. First, the CI server compiles the code, and if the build got successful, different automated testing practices such as unit tests run to ensure the application is bug-free. This process repeats every time developers push code changes to the repository. If the build or test processes failed, the CI server immediately sends those feedback to the development team. Then developers could attend to fix the bugs and resend updated codes to the code repository again. This approach stops the bugs enter to the production stage by capturing them at the early stages of the development, and it also helps to save time and resources.
Continuous Delivery
Continuous Delivery is the next step towards the production of software applications. It reduces the complexity of the release process by automating the deployment phase of the pipeline. In continuous delivery, developers do not have to be involved in time-consuming release processes, ensuring the fast and continuous deployment of software. Also, traditional weekly or monthly release cycles replace with multiple releases per day. Automated testing procedures such as integration tests and QA tests can be run during this stage. Continuous delivery involves a manual step that allows the business team to decide when to deploy the software to the production environment. Apart from that, other deployment steps are still automated.
Continuous Deployment
Continuous Deployment releases well-tested software applications into the production environment. No developer’s intervention is required for this stage, and only the failed testing halts the deployment process. It also avoids the manual step that involves continuous delivery and automates the entire deployment process. Continuous deployment ensures that software application releases to the production environment quickly after the developers’ job. It improves the end users’ experience by the faster deployment of bug-free software.
Benefits of CI/CD pipeline
The main objective of adopting a new software development methodology is to build a quality, reliable and robust software product. These are some benefits that can be gained by adopting the CI/CD pipeline.
Enhance the quality
The shared code repository in the CI/CD pipeline allows developers to push their codes to a common storage place. This enables developers to share their part with other team members, and also code repository provides version control capabilities. This approach enhances the overall quality of the code. By automating all the processes from build to deployment, CI/CD pipeline enables the faster delivery of high-quality products to customers.
Cost reduction
CI/CD pipeline eliminates the repetitive manual tasks by automating the build, test, and deploy phases in the pipeline. Automated test environments significantly reduce the time and resources related to software testing. Automation also gives developers more time to focus on coding. Overall, automation in CI/CD approach reduces the cost of the software development and increases the ROI of the business.
Reliable releases
CI servers continuously alert the development team about anomalies and errors in the build and test phases. This type of faster communication model allows developers to fix issues as soon as alerted. Whenever the code repository is updated with new code lines, the CI server starts all the automated phases in the pipeline. This repetitive and faster build, test, and bug-fixing mechanism eventually deliver a reliable software product to end-users.
Easy maintenance and updates
User requirements and market trends change frequently. The CI/CD model allows developers to add new features easily to the software when required.
Maintenance is an essential part of keeping up the quality of the software after released to production. In CI/CD pipeline, maintenance works perform during non-critical business hours. This ensures the continuous performance of the system during business hours.
Customer satisfaction
Customer satisfaction is one of the main goals of any business because positive customer feedback is vital to the business's future. The CI/CD pipeline always keeps the customers happy by delivering well-tested bug-free products. It also enables the faster addition of new features and support, which leads to a satisfied customer base.
