Continuous integration (CI) is a software development strategy that automates merging code changes from multiple developers, frequently running automated builds and tests to ensure correctness. It quickly detects errors, making it easier to locate issues by integrating small changes regularly.
Without CI, developers would have to manually coordinate and
communicate their individual code contributions to the end product. A
non-CI environment requires unnecessary bureaucracy and a complex
synchronization, which creates a situation that is more complex than it
needs to be.
There is a likelihood of a communication breakdown between the engineering team and the rest of the organization, particularly product and engineering. The time from development to product launch is largely unknown due to the time and complexity of integrating new changes that are not stored in a single repository or location.
CI, CD, and continuous deployment are each crucial parts of the software release lifecycle, including DevOps processes.
Generally, CI is used with agile software development, which helps an organization compile tasks into a list and product roadmap. Once outlined, the tasks are outlined to different team members for fulfillment. The several codes are then merged into a master code repository.
CD is the second part of the process. It involves the packaging of code together, which is then ready to be delivered to end users. This step of the process typically runs automated tools that generate an artifact, which makes it ready to deploy to end users at any time.
This final phase of the process, continuous deployment automatically launches the software product to end users, which means it has successfully passed integration and delivery. The automation utilizes scripts or tools that transfer the software product to public servers or other means of public distribution. In a highly automated and well-governed environment these deployments happen automatically as soon as the product is delivered (hence continuous). Some teams or some products may instead be deployed at specific times or after other processes and checks have completed.
CI’s iterative approach makes it possible to streamline and optimize the software development practice. Code changes are continuously being integrated throughout the development process (typically multiple times per day), aided by automated testing stages to ensure that every modification operates as intended. This process allows for several clear advantages:
The minimization of code bureaucracy can help DevOps and agile workflows work effectively and smoothly, from the development of new code through the end of the cycle. CI can help a company scale when it removes dependencies that stand in the way of the development of individual features. Even though a developer works in a silo, they can do so knowing that their code will be integrated with the rest of the code repository.
Business decisions receive faster feedback on business decisions, which can help product teams test their ideas and better work with iterative product design. Changes can be rapid, measured, and successful, and bugs can be quickly addressed and corrected.
Engineering teams can better communicate and be held accountable, which allows for better communication in a DevOps team. Teams have the opportunity to view and comment on code written by other team members, which also provides the opportunity to collaborate on future code with other developers.
By frequently integrating and testing code changes, CI makes it possible for teams to identify and address bugs almost immediately. This near-constant process ensures that issues are caught and resolved early in the development lifecycle, reducing the time and resources required to fix bugs while maintaining high code quality.
Continuous integration supports a more rapid delivery of product updates and features to the market. Automating the build and test processes, CI minimizes manual intervention, thereby accelerating the path from development to deployment. This efficiency enables companies to respond more swiftly to market demands and customer needs.
Through it all, the regular, incremental improvements and the early issue detection contribute to a more stable and reliable software product. This stability is crucial for maintaining user satisfaction and trust. Moreover, the ability to quickly roll out new features and enhancements in response to user feedback allows companies to continuously refine the user experience, ensuring it meets or exceeds customer expectations—even as those expectations evolve.
The continuous integration/continuous deployment (CI/CD) pipeline is a fundamental concept in modern software development, representing a systematic, automated process that guides code from inception to deployment. This pipeline encompasses several key stages, each designed to ensure that code changes are integrated, tested, and released efficiently and reliably. Beginning with version control and moving through building, testing, and deployment, the CI/CD pipeline embodies the principles of continuous integration and continuous delivery, aiming to reduce manual effort, minimize errors, and speed up the delivery of software updates.
Here, we break down the pipeline into its essential components:
Code is run through version control software, such as apache subversion or git, and the commit history of the software code is committed so that it can be changed if needed.
Developers build out their code, and the code is passed through the version history system. The code is then returned to the build phase for compilation.
Software undergoes testing, including the unit test that tests the units of software. The staging phase begins after successful testing, which means it is ready to be deployed into the staging process. Here, the code is viewed and finanlized before the final testing phase.
After the software has been in the staging environment, it undergoes automated tests that are prepared for the software. Once the software passes the automated tests, it is sent to the deployment phase.
After the automated testing has occurred, the software is deployed to production. If there are any errors during the testing phase or subsequent deployment, the software returns to the version control procedure and is inspected for errors. If there are any errors identified, they are corrected.
The CI methodology hinges on a series of critical steps, each designed to optimize efficiency, enhance code quality, and reduce the time to market for new features and fixes. Although individual businesses may have their own ways of categorizing the different phases of continuous integration, the following phases are typically part of every CI strategy.
Each artifact that is needed to build a project should be placed in a central code repository. This allows for integrated changes to be maintained rather than having individual versions existing simultaneously. This type of shared repository is most effective when developers take extra care to ensure that each ‘commit’ (source code change sent to the repository) passes through an extra verification layer in the form of local unit testing.
This step involves selecting the appropriate development and delivery approaches that will align with your project's objectives and the team's capabilities. Choosing a development strategy, such as SCRUM or Kanban, enables your team to work in small, manageable increments. Similarly, deciding on a delivery strategy hinges on the project's end goals. and should cater to the specific needs of the project, ensuring that the final product can be delivered efficiently and effectively to the end-user or environment.
As automation is such a central aspect of continuous integration, this stage is a prerequisite for any testing or deployment to come later. A build automation tool will act as the central dashboard for test automation, orchestrating the CI process by connecting all components through build steps. Each step can execute distinct tasks, such as running scripts or managing code checkouts. The tool monitors the outcome of each step, ensuring that only upon their successful completion does it compile a new, potentially releasable software package.
Integrating unit testing into the CI process is crucial for validating the functionality and reliability of individual code segments. These tests are automated to run with each build, ensuring that latest changes do not adversely affect existing functionality. By identifying and fixing issues early, unit testing helps maintain code quality throughout the development lifecycle. This step reinforces the foundation for a stable software product, aligning with continuous integration's goal of early defect detection.
Next, a dedicated test environment, mirroring the production setup, should be established to evaluate the software under conditions that closely resemble its final deployment. This environment is crucial for detecting issues that may not emerge in development, offering a realistic assessment of the software's performance and behavior and ensuring a seamless transition to production.
Implement a clear, automated process for reporting failed tests. This system will need to alert developers immediately when a test fails, providing detailed feedback and logs. This prompt reporting enables quick identification and resolution of issues, so that the momentum of development isn't interrupted.
Regular backups of the codebase, test environments, and build artifacts are critical for safeguarding against data loss and ensuring continuity in the development process. This final step provides a safety net, allowing teams to quickly recover from unforeseen incidents without significant impact on the project timeline or quality.
Continuous integration has the potential to revolutionize how you approach software testing and deployment. To turn that potential into a high probability, consider the following CI best practices:
Test drive development
Prioritize developing and expanding test coverage alongside your project's growth within the CI pipeline. Accompany each new feature with tests to confirm its functionality aligns with expectations.
Pull requests and code reviews
Utilize pull requests as a fundamental component of CI, facilitating automated and manual approvals through a review process. This encourages constructive feedback and ensures code quality.
Commit regularly to the baseline
Minimize the risk of conflicts and maintain project momentum by committing changes daily. Regular commits aid in early problem detection and resolution.
Maintain rapid build processes
Aim for quick build times to identify and address integration issues efficiently, enhancing the feedback loop.
Replicate the production environment for testing
Establish a test environment that mirrors production to catch potential deployment failures early, reducing the risk of real-world issues.
Make latest builds easily accessible
Ensure stakeholders and testers have easy access to the most recent builds, facilitating early and frequent testing.
Ensure transparency among team members
Enable team members to easily identify and address build failures, promoting a culture of accountability and continuous improvement.
Automate deployment post-build
Implement scripts for deploying applications to live testing servers, allowing for immediate feedback and adjustment.
Optimize pipeline speed
Regularly evaluate and enhance the CI pipeline's efficiency to support a faster development cycle and improve overall software quality.
Treat every master build as potential release
Operate under the assumption that any build could be released, addressing failing tests by fixing them rather than bypassing them, and ensuring the build is never left broken.
Parallelize your tests
Segregate tests by type and employ tools that facilitate parallel execution, reducing overall test time.
Frequently commit code (multiple times per day)
Encourage frequent commits to the master branch to avoid complex merges and develop features iteratively, using feature flags to manage visibility.
Pull requests after passing tests
Open pull requests only after tests have passed to respect the time of reviewers and maintain code quality.
Automate maintenance
Schedule workflows to update libraries and dependencies automatically, keeping the codebase current and secure.
Monitor key metrics
Keep a close eye on CI build times and the health of the master branch to promptly address any issues and maintain a smooth development process.
You can leverage CI/CD when building apps on the ServiceNow platform. You can also connect your CI/CD tools to ServiceNow’s DevOps product to link the work that is moving through the CI/CD pipeline to the work that is managed in ServiceNow. The ServiceNow DevOps product can provide many benefits to the CI/CD process whether you are building on the ServiceNow platform or outside of ServiceNow in tools like Azure DevOps, GitLab, or Jenkins.
Manage code changes effectively for multiple developers when using Git repo integration and make a connection between work items like user stories and the commits in the repo. With the additional connection of commits to test results and changes in ServiceNow you obtain a complete end-to-end view of the pipeline.
Automate change creation, approval, and deployment and move from development, through testing, and into production more quickly and efficiently.
Deliver applications faster to help teams iterate faster on feedback both early and often.
Report on the entire pipeline or value stream from ideation to production. Communicate across teams, compare performance across disparate tools and identify and resolve bottlenecks.