One of the biggest concerns in software development is the challenge of delivering flawless systems that actually make sense for the needs of users. 

In order for this to be possible, it is essential to use tools and processes that assist in the creation of the software and, in this way, reduce some complex steps regarding such activity. In this sense, we have the concepts of continuous integration and continuous delivery.

In case you do not know — exactly — what CI and CD are, be sure to read this article specially prepared on the subject as it will also help you understand the differences between them and how both are applied in practice.

What is Continuous Integration (CI)?

CI stands for Continuous Integration, and it is a software development practice in which developers frequently integrate their code into a shared repository.

Therefore, with the deployment of Continuous Integration, each integration process is automatically verified through automated tests. This allows developers to detect and fix problems at much earlier stages, which helps reduce the risk of bugs and conflicts between code developed by different team members.

What is CD (Continuous Delivery)?

CD stands for Continuous Delivery, which is an extension of the CI practice, in which code changes go through an automated testing process, and, if approved, are automatically deployed to a production environment or a homologation environment for customer validation.

Continuous Delivery helps ensure that the software is always ready to be deployed in production, allowing teams to deliver new functionalities demands faster and more securely—serving the interests of the business and its stakeholders.

In summary, CI and CD are software development practices that help automate the process of testing and deploying new features, making processes faster, safer and more reliable, whether for “off-the-shelf” software or bespoke systems.

Read also: How much does tailor-made software cost: learn how to calculate and project values

How are IC and CD used?

The application of IC and CD arises from processes with several stages, where different actions are performed in order to ensure the quality of the project as a whole. In the case of continuous integration, there are 7 main steps:

1. Environment configuration: It is necessary to define a development environment with a CI infrastructure, including a continuous integration server, as well as test and deployment automation tools;
2. Code versioning: It is important to use a version control system in order to store the project’s source code and record all changes made by developers— that typically being the software known as Git;
3. Automated test creation: Automated tests are created in order to ensure that code changes do not adversely affect the system. Testing includes, for example, unit, integration and acceptance tests;
4. Frequent integration: Each time a developer completes a code change, they commit to the version control system and start a continuous integration process, which compiles the code, runs the tests, and checks for conflicts with the existing code.
5. Error notification: If there are build errors or test failures, the continuous integration server notifies developers through communication tools such as email, instant messaging, or even Slack channels.
6. Bug fixes: Developers should fix bugs as soon as possible, and make a new “commit” in order to start a new continuous integration cycle.
7. Continuous integration: If tests get a pass, code is automatically deployed to a homologation or production environment, depending on CD configurations.

Continuous delivery follows the same line of application as the IC, in which several steps form the process for the publication of software to be done regularly. In order to do that, there are also 7 steps to perform:

1. Environment configuration: It is necessary to define a deployment environment with a CD infrastructure, including a continuous deployment server and deployment automation tools such as scripts or containers;
2. Deployment automation: It is advisable to automate the deployment process, including setting up the environment, installing dependencies, and running scripts in order to configure the application.
3. Definition of the deployment flow: It is important to define a deployment flow for each environment, including the approval environment and the production environment, specifying the deployment steps and the tools that will be used in each step;
4. Configuration of environment variables: It is important to set the environment variables for each environment, including database access credentials and other environment-specific settings;
5. Final testing: It is important to perform final testing in each environment, including load testing, security testing, and integration testing, in order to ensure that the software is ready to be deployed in production.
6. Continuous deployment: If the final tests get a pass, the code is automatically deployed to a production environment. Depending on the configurations, it might be necessary to run a final review before performing the deployment;
7. Monitoring and feedback: It is important to monitor the production environment after deployment in order to detect potential errors or performance issues, and to provide feedback to developers in order to improve the software.

It is important to emphasize that these steps are repeated continuously throughout the project lifecycle, ensuring that code changes are implemented quickly and more securely—even if minor bugs arise.

What is the difference between CI and CD?

Although similar, there are a few differences between CI and CD in the software development cycle. The CI is responsible for testing and preparing the system for a homologation environment (internal, from within the team), while the CD does the same process, but puts the project in the production environment thus making it available to all users.

That said, both are essential approaches to developing quality software and aligning with the needs of users/customers.

Read also: What is software refactoring and when to do it + 5 refactoring techniques