Continuous integration, continuous delivery, and continuous deployment (CI/CD) are the practices that make up the pipeline. The CI/CD pipeline is a mechanism for building, testing, and deploying code that is frequently used by DevOps teams. DevOps teams will see more frequent and dependable upgrades to their software and applications, as well as a more collaborative and agile workflow.

What is CI/CD PIPELINE?

It is an agile DevOps workflow that aims to provide software often and reliably through the continuous integration/continuous delivery pipeline. CI, testing, delivery, and deployment procedures are all part of the framework, which is called Continuous Integration (CI). Together, they provide a pipeline for the production of high-quality software and applications.

Code updates are pushed via the CI/CD pipeline and delivered to production environments using automation to discover possible issues earlier. It is crucial for pipeline quality control to use test automation, which measures everything from performance to API and security.

Automation of CI/CD pipeline stages results in more reliable, faster, and better-quality software and app releases overall.

What is Continuous Integration (CI?)

We are going to start with continuous integration in the CI/CD process. It is a collection of procedures allowing development teams to build, package, and test programs in a consistent and automated manner. Teams can automate functionality and unit tests by making minimal changes to existing code or by writing new code entirely. When a new version of a program is being developed, iterations and bug detection are carried out automatically through the use of integration tests. The continuous framework methodology is predicated on CI.

What is Continuous Deployment (CD?)

Continuous deployment can also be referred to as “CD” in the CI/CD process. Continuous deployment automatically delivers code updates to end-users after passing a sequence of specified tests, such as integration tests that test code in a simulated environment in order to ensure the integrity of code. Continuous deployment.

What is Continuous Delivery (CD?)

Following continuous integration’s validation, continuous delivery distributes the code changes to selected environments or repositories (e.g., GitHub or a container registry). Updates, new features, and bug fixes are all examples of code modifications. Deployment time is reduced, costs are reduced and software is scaled using automation in CD.

Phases of CI/CD Pipeline

The continuous framework phases comprise the development lifecycle and workflow from source code to production.

The following are some of the possible steps in a CI/CD pipeline:

• Source: A new instance of the pipeline is started when a change is made in an app’s source code, configuration, environment, or data.

• Build:  A continuous integration phase is one in which code is written and then compiled. As a team builds off of the source code and incorporates new code, the team immediately identifies and resolves any issues.

• Test: Tests all aspects of the program, from the source code to the executables and everything in between. Continuous delivery and deployment both include the use of automated tests.

• Deliver: An authorized codebase is sent to a production environment in this instance. This stage is automated in continuous deployment, but only after developer permission in continuous delivery.

• Deploy: The finished product is deployed into production. Automated and continuous deployment are the modes of operation for this level. When using continuous delivery, items or code are first sent to repositories, where they are then approved by humans before being deployed. Verifies performance and security before releasing the software into the wild.

Set up a code repository and version control system for the source stage

First, the source code is stored in a repository with a version control system (VCS) that facilitates collaboration and tracking changes across a dispersed team. When a branch push or a pull request is validated, the VCS can activate a pipeline. Also, these pipeline runs can be planned or started by a user.

The things you should do at this point:

• Consider using a repository like Git or SVN.
• It’s important to decide whether or not you’ll host the VCS on your own or use a service like GitHub or Bit bucket.
• The application source code and pipelines should be stored in separate repositories.

Compile the code, run the checks, and select a CI engine

Providing early feedback and keeping the application in a state where it can be released to an environment are the major goals of this stage of the Continuous Integration/Continuous Delivery (CI/CD).

Giving immediate feedback once a developer checks in new code helps identify and fix any problems with syntax or compilation that may arise. Further down the CI/CD pipeline, compilation verifies that the code may successfully generate artefacts for release.

The things you should do at this point:

• Build and CI servers can be self-hosted, such as Jenkins or Jenkins X, or third-party, like GitHub Actions, Circle CI, or Azure Pipelines.
• A pipeline-as-code setup is ideal. A branch push or a pull request can be used as a release trigger for this information, which can be saved in a version control system such as Git.
• Compile (build) the application source code into a stage/job in the pipeline. It is possible to create a Docker image in this stage for cloud-native applications.
• No “code smells” (indicators of deeper problems to investigate) should be found in the code. Also, the coding style should be aligned with organizational requirements. Static analysis and warnings can be performed by many plugins in a CI engine.
• Finally, an artefact or container image is created as a result of the workflow. Make this build artefact available for testing or deployment by putting it in a store or feed (or a container image in a registry).

The build is tested, the findings are published, and the build is released into production.

The purpose of this step is to guarantee that the modifications don’t disrupt any logic or functionality and that the code is safe to be released. When it comes to releasing code, testing serves as an insurance policy. Unit, integration, and functional tests are only a few of the many tests that take place during this phase.

If you need to replicate dependencies, you can use mocking to do so. Unit tests analyze small chunks of application code and only test the logic in isolation. These little units can be class methods in object-oriented languages like Java or C#.

Tests for integration analyze the code as a whole. This helps to ensure that the components that make up the application as a whole won’t fail during testing.

An end-to-end functional test simulates a production deployment by introducing the software into a test environment. Selenium, for example, can be used to automate this procedure.

The things you should do at this point:

• Plugins like XUnit and JUnit allow you to integrate the test runner of your choice into the pipeline.
• Make the results of the testing available in the pipeline run by publishing the test report and code coverage reports.
• To release a software build, you must meet a certain level of code coverage. Fail the stage if the code coverage falls below a predetermined level.

The final build is delivered and deployed at this step.

Finally, after testing and generating artefacts, the software is ready to be launched into the world. Artifacts should be deployed and tested in many environments before being released to production. If all tests are passed the release advances to production deployment. Additionally, this stage adds the resources needed to host the cloud-based application.

The things you should do at this point:

• Select a strategy for deploying the final version of the application to the production environment. Blue-green, canary, and rolling deployments are all popular techniques. If the deployment stack includes containers, orchestration technologies like Kubernetes or Open Shift should be used.
• IaC options, such as Terraform or AWS Cloud Formation templates or Azure Resource Manager templates can be used if you are deploying the application to the cloud. Make that your IaC path supports idempotent deployments, whichever one you choose.
• You may have to automate operating system configuration for CI/CD cloud deployments. Consider using technologies like Chef, Puppet, and Ansible to manage your system’s configuration.
• Think about combining tools like Jenkins and Spinnaker, which can be used for both cloud resource deployments and application release methods. Automating the deployment of infrastructure and applications is made easier by using a technology designed for continuous delivery.

Benefits of CI/CD Pipelines

Automating the software release process is the most significant advantage of a CI/CD pipeline.

The following are additional advantages of using the CI/CD approach for development teams:

• Automation has shortened the time it takes to deploy a system: In order to speed up the development process as a whole, developers might use automation in continuous delivery and continuous development.

• Improved communication and cooperation among team members, and better system integration: Code changes, feedback, and issues are handled rapidly by everyone in the team.

• The capacity to identify and fix errors sooner in the development process has been improved: Every time a new version of code is built, an automated test is run to look for problems with integration. The earlier these problems are identified and corrected, the easier it is to fix them.

• Software development expenditures have been cut significantly as a result: Because automation speeds up development, testing, and production, it also reduces costs.

• Feedback is a constant source of improvement: It’s a continuous build, test, and deploy process. Every time a piece of code is put to the test, the developers can immediately act on the results of the test and make changes to the code.