Circle CI

Circle CI is a cloud-based continuous integration platform that automates development processes. With Circle CI, the continuous integration and deployment are orchestrated through a single file called config.yml in a folder called .circleci at the root folder of our repository. Circle CI uses the YAML syntax to define configurations on how a pipeline should be built. Everything starts with the project in Circle CI.

Project

A project in Circle CI is the repository we want to configure a pipeline for. This takes the same name as the name of our project in a GitHub repository.

Configuration

A project configuration is the YAML file .circleci/config.yml that contains the definition of the CI pipelines that Circle CI uses to execute our project. Within a Circle CI configuration, there are steps, jobs, and workflows.

Steps

A step is a command we want to execute, such as installing dependencies, building a Docker image, or running a shell script.

Jobs

A job is a combination of one or more steps. It’s responsible for running a series of steps that perform a command.

Workflows

Having steps and jobs isn’t enough; it’s also important to be able to control the order at which jobs run. We also need to know what to do when a job fails. The workflow is used to orchestrate multiple jobs.

Orbs

Orbs are reusable packages of the YAML configuration that condense repeated pieces of config into a single line of code. We can use any of the available orbs from the orbs registry, or we can create our own.

Executors

Executors are runners that run our jobs. Each separate job defined within our config will run in a unique executor. An executor can be a Docker container or a virtual machine running Linux, Windows, or macOS.