GitHub Actions

What is GitHub Actions and why do we need it?

• It is a CI/CD platform that allows you to automate your build, test, and deployment pipeline.
• It is useful to automate developer workflows.
• Github provides Linux, Windows and macOS virtual machines to run your workflows or you can host your own self-hosted runners in the data centre or cloud infrastructure.
• We don't need any third-party tool like Jenkins for Continuous integration.
• At a time, we can test and build our code in different Operating Systems.
• By using GitHub Actions you can run a workflow that tests and builds your code.

What is a workflow?

A workflow is a configurable automation process that will run one or more jobs. A YAML file defines workflow in the .github/workflows directory and runs whenever an event is triggered in the GitHub repository.

Ex: Whenever someone raises a pull request or pushes a commit to your GitHub repository, you want to ensure that new changes shouldn't break the existing code and pass all the tests and build.

How can we trigger a workflow?

• We can trigger a workflow by using events or by scheduling also.
• An event is a specific activity in a repository like opening a pull request, deleting a branch, pushing a commit to the repository, open a new issue. etc

What is meant by jobs?

• A job is a set of steps in a workflow that is executed on the same runner.
• Each step is either a shell script that is executed or an action to be run.
• Steps are dependent on each other so we can share data among that.
• By default jobs will run in parallel in a workflow.

In the above example, testing your code is one job and building your code is another job

What is meant by actions?

• An action is a reusable unit of code that performs a specific task for a workflow.
• Actions are building blocks of GitHub workflows that automate tasks such as testing, building, and deployment.
• Ex: For any workflow pulling the latest code from the GitHub repository to the current virtual machine is necessary. So GitHub provides an action (actions/checkout@v2) that we can directly use in our workflow.

What is meant by a runner?

• A runner is a server that runs your workflows when they are triggered.
• Each runner can do a single job at a time.
• Each workflow runs in a fresh, newly provisioned virtual machine.

Sample YAML file

Thanks for reading ??

In the next article, we will see a detailed way to create and run a workflow with one real-time use case.