CircleCI

CircleCI is a platform / product for Continuous Integration and Continuous Delivery.

It integrates with Github (and Github Enterprise) and Bitbucket. (i.e. Not compatible with Gitlab, which has its own workflow).

Setup

2 Steps:

1. Presence of .circleci/config.yml file in Github repo
2. "Set Up Project" for that repo on app.circleci.com

Config.yml File

Varies depending on complexity of application

Configuration Reference

Generally a good structure to list out 'jobs' (tasks) at the top and workflows (jobs to perform) below

version: 2.1
jobs:
    build-and-push-docker-image:
        docker:
            - image: cimg/base:stable-18.04
        steps:
            - checkout
            - setup_remote_docker
            - run:
                name: Build Docker Image
                command: |
                    ls -lah ./
                    echo '^^^ ls current working directory ^^^'
                    docker build -t docker-repository/image-name .
            - run:
                name: Push To Dockerhub
                command: |
                    docker build -t docker-repository/image-name .
                    echo $DOCKERHUB_PASS | docker login -u $DOCKERHUB_USERNAME --password-stdin
                    docker push docker-repository/image-name
workflows:
    update-docker-image:
        jobs:
            - build-and-push-docker-image

Isolating Git Branches

Use Cases: - Deploying to a production environment, staging environment, and testing environment based on git branch - Not wasting resources trying to test / deploy branches that are for development / breaking changes

In config.yml, add filters: property to jobs that should only run when code is committed to specific branches

workflows:
    update-docker-image:
        jobs:
            - build-and-push-docker-image:
                filters:
                    branches:
                        only: main
    update-production-docker-image:
        jobs:
            - build-and-push-docker-image:
                filters:
                    branches:
                        only: production

Prevent Typo Hell

Requires CircleCI Local CLI

Use circleci config validate from the project root directory to validate config file before pushing to version control.

NOTE Install Local CLI (sudo to install to /usr/local/bin): curl -fLSs https://raw.githubusercontent.com/CircleCI-Public/circleci-cli/master/install.sh | sudo bash

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Last update: June 7, 2023
Created: June 7, 2023