Welcome to the 4th day of the DevOps masterclass! Today, we’ll begin by exploring Continuous Integration (CI), referred to in short as CI.

Key points for today’s session:

Continuous Integration (CI): We’ll commence by delving into CI, its significance, and its role in modern software development.

Challenges without CI: We’ll examine the challenges that emerge when CI is absent from our software development lifecycle. These challenges include issues with integration, delayed feedback, inconsistent builds, and increased risk.

CI’s Relationship with Continuous Delivery and Continuous Deployment: Next, we’ll discuss how CI aligns and works in conjunction with Continuous Delivery (CD) and Continuous Deployment (CD) to ensure a seamless software development and delivery process.

Jenkins and GitLab in CI: Finally, we’ll explore the reasons why Jenkins and GitLab are pivotal tools for implementing CI in software development. We’ll highlight the specific advantages and features that make these tools essential for effective CI processes.

Let’s dive into Continuous Integration (CI). Essentially, CI is a process involving automated builds and tests. When we refer to automated builds and tests, it involves understanding a specific scenario within our development and QA teams working on an application, potentially comprising ten or fifteen developers.

All these developers are consistently pushing their code to a central shared repository. Jenkins, GitLab CI, or similar CI tools are then utilized to pull this code from the shared repository. Subsequently, the CI tool builds the code using appropriate build tools such as Maven, Gradle, React, or Next.js. Once the build is successful, tests are executed on this particular build, thus defining the process of continuous integration.

It’s important to note that while automated tests are not inherently part of continuous integration, extending the continuous integration process to include automated tests is beneficial. CI primarily focuses on automated builds, but integrating automated tests amplifies its effectiveness.

CI serves a vital role in swiftly detecting errors and aiding in their identification. For instance, consider building your project using CI every two hours. If the project is built at 2 PM without any issues, but errors surface in the 4 PM build, CI facilitates pinpointing changes made between these two builds, simplifying the process of locating and resolving errors.

Therefore, continuous integration expedites error detection and eases the process of error localization, significantly contributing to more efficient and streamlined software development processes.

WITHOUT CI PROBLEM
In a scenario without CI, developers frequently modify the source code repository. However, these changes are merged into the master branch only periodically, typically once a week or every night. Consequently, when the project undergoes a build within the master branch after these merges, numerous defects surface, ranging from compilation errors to genuine product failures or defects.

The process of identifying and notifying developers about these defects becomes time-consuming. This delay occurs because the code changes made by developers in the morning are merged in the evening, followed by the execution of automated builds, which can take anywhere from 4 to 6 hours. Only after this lengthy process, the results become available, making it challenging to manage the entire process effectively.

Furthermore, this delay significantly impacts the release process. With defects being reported late, developers are not promptly informed about the bugs in their source code. The merging of developers’ source code with the integration branch may lead to compile-time errors and merge conflicts, further complicating the release lifecycle.

Ultimately, the absence of CI creates a scenario where companies face challenges in promptly identifying and addressing defects, leading to a significant delay in the product release cycle. This delay can adversely affect the overall efficiency and quality of the software being developed.

WITH CI
Let’s consider a software development team working on an e-commerce platform. They’ve implemented CI practices into their workflow using Jenkins as their CI tool. In this CI setup, each time a developer makes changes to the codebase, they commit these changes to the shared repository hosted on GitLab.

As soon as the changes are pushed to the repository, Jenkins, configured to monitor this repository, automatically triggers a build process. It fetches the latest changes, compiles the code, runs automated tests, and generates a build artifact. Let’s look at the advantages this CI setup offers:

Swift Error Detection: Imagine a scenario where a developer inadvertently introduces a bug while implementing a new feature. With CI in place, Jenkins promptly identifies this issue during the automated build and test phase. The developer receives immediate feedback, allowing them to rectify the bug swiftly.

Efficient Collaboration: Multiple developers are simultaneously working on different parts of the e-commerce platform. CI ensures that their code changes are continuously integrated, minimizing integration conflicts. Any discrepancies or merge issues are flagged early in the process, fostering efficient collaboration among the team members.

Enhanced Code Quality: By running automated tests after each code change, CI ensures that the codebase remains stable and functional. This consistent verification helps maintain high code quality throughout the development lifecycle, reducing the chances of critical bugs slipping through.

Accelerated Release Cycles: With CI automating the build, test, and integration processes, the development team gains the confidence to release new features more frequently. As each change is thoroughly tested and validated, the risk associated with deploying new updates decreases, enabling faster and more reliable releases.

Improved Productivity: CI reduces the time spent on manual tasks related to build and test processes. Developers can focus more on coding and innovation, knowing that CI will handle the repetitive and time-consuming tasks efficiently.

In summary, the implementation of CI through tools like Jenkins and GitLab enables the software development team to detect errors early, collaborate seamlessly, maintain code quality, expedite release cycles, and ultimately enhance productivity. This real-life example illustrates how CI practices can significantly benefit a software development process in a dynamic and fast-paced environment.

How CI Ties with CD

CI (Continuous Integration) and CD (Continuous Delivery) are closely related practices within the software development lifecycle, and together they form a seamless pipeline for building, testing, and delivering software.

Continuous Integration (CI):

CI is a development practice that involves regularly integrating code changes from multiple developers into a shared repository. It aims to automate the process of code integration and verification.
Developers frequently commit small changes to a version control system like Git. These changes trigger an automated build process, allowing the code to be compiled, tested, and verified in an isolated environment.
CI ensures that code changes are continuously validated, enabling early detection of integration issues and bugs. It helps maintain code quality, speeds up development, and reduces the risk of conflicts when merging changes.
Continuous Delivery (CD):

CD extends the principles of CI by automating the software delivery process beyond testing to make deployments to production or staging environments easier, faster, and more reliable.
Once code changes pass CI tests, CD automates the process of packaging, deploying, and releasing the application to various environments, such as staging or production.
CD emphasizes having a reliable and automated pipeline, enabling the deployment of tested code changes quickly and frequently to make software releases more predictable and less error-prone.
The goal of CD is to have software in a deployable state at all times, allowing teams to release software to production at any moment with minimal manual intervention.
Relationship between CI and CD:

CI is the foundation of CD. It ensures that code changes are continuously integrated, tested, and verified. Successful CI builds are the prerequisite for further automated deployment in CD.
CD builds upon the successful CI process by automating the steps beyond testing, including deployment, infrastructure provisioning, and release, leading to a streamlined and efficient delivery pipeline.
Together, CI and CD create an automated and efficient workflow that enables development teams to deliver high-quality software continuously, rapidly, and reliably to end-users.
In summary, CI focuses on automating the testing and validation of code changes, while CD extends these principles to automate the deployment and delivery process, allowing for frequent, reliable, and automated software releases.