What is Continuous Integration?

Continuous Integration(CI) has now become a cornerstone for the successful implementation of DevOps as well as the Agile methodology of software development.

By definition, it is the practice where the developers integrate their code changes to a shared source code repository multiple times a day to ensure that the repository reflects the latest changes at all times. The practice is also extended to automatic creation of the build and execution of automated tests that test the code to make sure that the integration does not break in the process.

Importance of Continuous Integration

On successful implementation, continuous integration helps to achieve multiple goals that help enable timely releases to the market keeping the quality intact. Continuous Integration becomes quite a necessity If there is a team with multiple developers that are checking in their code into the shared repository.

Below are some points that make it important and beneficial:

What Continuous Integration does?

There are a few changes that happen when continuous integration is implemented by a team following software development methodology:

How can Continuous Integration be used?

CI or Continuous Integration is a process and for a team to be able to use it effectively, there are some steps that need to be followed for its setup and some ground rules that need to be set for use.

Below is how the process looks like:

Process Of Continuous Integration

A successfully implemented continuous integration process looks like below in terms of steps:

To set up an efficient continuous integration process, below steps need to be performed:

  1. A version control system needs to be set up such that every check-in can be treated and stored as a separate version. Few majorly used VCS are Git, mercurial, subversion.

  2. A version control hosting platform that can host the code with VCS functionalities is needed above the VCS.

  3. A Single Source code Repository should be set up.

  4. The process of building the code should be automated.

  5. There should be tests in place to verify the correctness of the code.

  6. Every Developer should commit to the mainline at least once daily.

  7. Every Commit Should Build the Mainline on an Integration Machine.

  8. If the build breaks, the fix should be done immediately.

  9. At all times, it should be ensured that the build creation process should be fast.

  10. The testing should be done in an environment that is a close copy of the Production Environment.

Below is what continuous integration can be used to achieve:

Continuous Integration vs Continuous Deployment vs Continuous Delivery

Continuous Integration, Continuous Delivery, and Continuous Deployment are the terms used to signify the automated processes of “Integration”, “Delivery” and “Deployment” respectively.

Continuous Integration is a combination of regular integrations from the developers on the source code repository and steps to approve the integrations.

Continuous Delivery is “automated release process” added to the continuous integration process which means that after the integrations done by a developer are approved, they are prepared into a build that is ready to be deployed. These builds can then be deployed as and when needed.

Continuous Deployment is the “automated deployment process” added to continuous delivery which means that after the builds are automatically prepared they are also deployed to the production every single time.

Continuous Integration vs Continuous Deployment vs Continuous Delivery

What are the benefits of each practice?

Benefits of Continuous Integration:

Benefits of Continuous Delivery:

Benefits of Continuous Deployment:

Benefits and challenges of continuous integration

Continuous Integration has been a key process in the DevOps industry for some time now, and it is not without reason. Some benefits of practicing continuous integration are as below:

Challenges of using/implementing continuous integration are as below:

Getting started with continuous integration

To get started with Continuous Integration, take below steps:

  1. Start putting checks in place for testing and approving the code, for eg. writing test cases to test the code.

  2. Setup a main source code repository over a version control system

  3. Install a CI(Continuous Integration) service to run tests automatically after every integration.

  4. Ensure that the check-ins happen regularly, at least once every day by every developer on the team.

  5. If there are any errors or failures encountered they should be fixed without any delay.

  6. For every new feature or a change to the code, new tests should be added if needed.

How Does Continuous Integration Work?

Below are the main steps that go into the working of the Continuous Integration Process:

  • A developer checks in the code to the main repository.

  • The code builds to check on any compilation or integration issues.

  • The automated tests are executed to test the code.

  • A report of the result of the test execution is sent to all the stakeholders.

  • If the tests pass, an executable is created and shared and a developer is free to do another check-in.

  • If the tests fail, the concerned developer works on a fix and a fix is checked into the system and again the same process can start.

How Continuous Integration Works?

Why Employ Continuous Integration?

There are few main goals for most of the software development companies these days, those are as below:

Because of the above requirements, the agile methodology for software development is widely adopted. To make the implementation of agile methodology a success and realize the above requirements, the practice of continuous integration is being taken up by the majority of organizations.

If you are following agile methodology and feel that following traditional integration methods is getting challenging, for eg. developers are spending too much time figuring out the problem after there were multiple merges from multiple developers, Or developers don’t remain in sync while working on different features. Continuous Integration is what you need to employ.

Continuous Integration best practices

To achieve the best results, there are few continuous integration best practices that are recommended to be followed:

Continuous Integration and Continuous Delivery

When developers do their integrations to the mainline frequently it becomes Continuous Integration and when these changes are always ready to be deployed to production it becomes Continuous Delivery. Thus, Continuous Delivery becomes the next step to Continuous Integration.

Continuous Integration Tools

Some CI tools are as below:

Comparison of continuous integration software

Tool Paid/Free Operating Systems Hosting
Jenkins Free Cross-platform On-Premise Or Cloud hosted
Teamcity Paid Windows, macOS, Linux On-Premise
Bamboo Paid Cross-platform On-Premise or hosted on bitbucket as cloud
Travis Paid Linux, Mac OS On-Premise or Cloud Hosted
Circle Paid Linux, iOS, Android Cloud Hosted
Codeship Paid Windows, macOS Cloud Hosted

Continuous Integration (CI) vs Continuous Deployment (CD)

Continuous Integration is a combination of regular integrations from the developers on the source code repository and steps to approve the integrations. When the developers integrate their code to the single source code repository frequently and receive feedback about the quality of their check-in in an automated way, the practice becomes continuous integration.

When the “release process” is added to the pipeline in addition to continuous integration it becomes continuous delivery. Here, the builds are automatically created after every check-in and are ready to be deployed to the production when needed.

How to maximize the value of continuous integration and continuous delivery (CI/CD)?

Continuous Integration and Continuous Delivery are one of the most important practices in the software development lifecycle that aim at making the integration and deployment quick and error-free.

Few best practices to maximize their value are as below:

Continuous Integration(CI) vs Continuous Delivery(CD)

Continuous Integration is a practice where code is checked in by the developers on the source code repository regularly and after every check-in, there are automated steps to approve the integrations. The integrated code is usually tested with the help of automated test cases that are executed after every check-in.

Continuous Delivery is “automated release process” added to continuous integration process which means that after the integrations done by a developer are approved, they are prepared into a build that is ready to be deployed. These builds can then be deployed as and when needed

Getting started with Continuous Integration and Continuous Deployment

To get started with Continuous Integration and Continuous Deployment, take below steps:

  1. Start putting checks in place for testing and approving the code, for eg. writing test cases to test the code.

  2. Setup a main source code repository over a version control system

  3. Install a CI/CD(Continuous Integration and continuous deployment) service to run tests automatically after every integration

  4. Ensure that the check-ins happen regularly, at least once every day by every developer on the team

  5. If there are any errors or failures encountered they should be fixed without any delay.

  6. For every new feature or a change to the code, new tests should be added

  7. After every check-in, automated tests should be run

  8. If the automated tests pass, use the CI/CD service to create a release build for every check-in.

  9. After the build is created, have an automated system in place using the CI/CD service to deploy the build on production

Continues Integration: Path towards agility and accuracy

Which is the best CI/CD tool?

Jenkins, today, is the most used CI/CD tool. It is also free and can be hosted on the cloud or used on any operating system. This is also an open-source tool and has elaborate documentation and help available on forums. Check out how test it is implemented in Testsigma

Hosted vs non-hosted options

When choosing what tool to use for CI/CD, sometimes choosing between hosted i.e SAAS tools or non-hosted ones that are hosted on your own premises becomes a challenge. Below are the pros and cons of both that can help decide:

Pros Cons
Hosted CI/CD tools
  • No need to maintain a dedicated hardware infrastructure

  • No need to worry about software updates and patches

  • Easily configurable

  • Easily scalable

  • Costs increase linearly as the team scales

  • The hosted options may not support all technologies and platforms if you decide to grow in the future

Non-hosted CI/CD tools
  • Could be easily extended to fit your needs

  • Can support multiple platforms and technologies when the need arises

  • Costs can be kept in check

  • Dedicated hardware needs to maintain on-premises

  • The hardware also needs software updates and patches to be taken care of

  • Though this is extensible, this also means that they will require more time and effort to set up

CI/CD for open source projects

Below are a few tools that have become popular in use with open source projects:

  • jenkins

    Jenkins

  • travis

    Travis

  • gradle

    Gradle

  • CircleCI

    CircleCI

  • Codeship

    Codeship

  • GitLab

    GitLab

  • Buildbot

    Buildbot

Key metrics for tracking CI

Adding tests to your CI/CD pipeline

Adding automated tests to your CI/CD pipeline is an important step to ensure that every build receives timely feedback on quality. These tests should be run soon after the integration to the mainline is successful. The report of the test execution should be shared with all stakeholders and any breakages or bugs introduced should be fixed as soon as possible.

Some best practices for adding tests to a CI/CD pipeline are:

Why do we need Continuous Integration?

Continuous Integration, when put in place, has a lot of advantages which are:

If your team has been facing any one of the problems as below, continuous integration is the solution you need to employ

Prerequisites for Continuous Integration:

The goal of continuous integration

The goal of Continuous Integration is to automate the integration and testing of every change done to the code base of a product and provide feedback for every change as soon as possible such that any bugs introduced can be fixed before any new changes are made.

Through automation and CI, testing teams can achieve 100% test coverage with zero defects within sprint timelines.

FAQs on Regression Testing

CI stands for Continuous Integration. Continuous Integration is a practice where code is checked in by the developers on the source code repository regularly and after every check-in there are automated steps to approve the integrations. The integrated code is usually tested with the help of automated test cases that are executed after every check-in. In the context of software engineering, CI/CD is the combined practice of continuous integration and continuous deployment.

CD stands for Continuous Deployment and is the “automated deployment process” added to the continuous integration process which means that after the integrations done by a developer are approved, they are prepared into a build that is ready to be deployed and then these builds are automatically deployed to production.

Because DevOps is a practice of bringing development and operations teams together and aims at improving the end-to-end processes in all aspects, Continuous Integration is a cornerstone of successful DevOps as it improves the most basic process of check-ins done by developers.

The main purpose of continuous integration is to provide feedback on every check-in done by a developer and enable them to push fixes before any other check-in is done.

In the context of software engineering, CI/CD is the combined practice of continuous integration and continuous deployment.