# Pipeline In the context of **CI/CD (Continuous Integration/Continuous Delivery/Deployment)**, a **pipeline** is an automated process that defines a series of steps or stages to take code from source control to deployment. It orchestrates and sequences the execution of various [[Job|jobs]] (such as building, testing, and deploying) to ensure that code changes are properly integrated, tested, and delivered. ## Key Components of a CI/CD Pipeline: 1. **Stages:** - **Stages** are high-level segments of the pipeline, such as "Build," "Test," "Deploy." Each stage can contain one or more [[Job|jobs]] that must be completed before moving to the next stage. - Stages help organize and logically group [[Job|jobs]]. For example, all testing [[Job|jobs]] might be in the "Test" stage. 2. **[[Job|Jobs]]:** - **[[Job|Jobs]]** are individual tasks or units of work within a pipeline. Each [[Job]] is a specific step in the process, like running unit tests or deploying an application. - [[Job|Jobs]] within a stage can often run in parallel if there are no dependencies between them. 3. **Triggers:** - **Triggers** determine when a pipeline should run. Triggers can be events such as a push to a repository, a pull request, or a schedule (e.g., nightly builds). - Triggers ensure that the pipeline runs automatically in response to changes in the codebase or on a set schedule. 4. **Artifacts:** - **Artifacts** are the outputs or products generated by [[Job|jobs]], such as compiled binaries, Docker images, or test reports. - Artifacts are often passed from one stage to another, such as from the build stage to the deployment stage. 5. **Environment:** - **Environments** represent the different deployment targets, such as "development," "staging," or "production." - The pipeline can deploy to different environments as part of its process, ensuring that code is tested and verified before reaching production. ## Example of a CI/CD Pipeline: 1. **Source Code Checkout:** The pipeline starts by pulling the latest code from the version control system. 2. **Build Stage:** Compiles the code, generates artifacts (like binaries), and stores them for later stages. 3. **Test Stage:** Runs various tests (unit tests, integration tests, etc.) to verify that the code works as expected. 4. **Deploy Stage:** Deploys the application to a staging environment for further testing or to the production environment for release. 5. **Notification:** Sends a notification (e.g., via email or a messaging platform) about the pipeline's success or failure. ## Purpose of a Pipeline: - **Automation:** Pipelines automate the process of integrating, testing, and deploying code, reducing manual effort and human error. - **Consistency:** Pipelines ensure that the same steps are followed every time, leading to consistent builds and deployments. - **Feedback:** They provide continuous feedback to developers, helping to catch issues early in the development process. - **Speed:** By automating and parallelizing tasks, pipelines can speed up the software delivery process, allowing for faster releases. In summary, a **pipeline** in CI/CD is a series of automated steps that move code through various stages of development, testing, and deployment, ensuring that each change is thoroughly tested and ready for production. --- Bibliography: - [CI/CD pipelines - gitlab.com](https://docs.gitlab.com/ee/ci/pipelines/)