GitLab CI/CD Basics | My New Hugo Site

Table of Contents

INTRODUCTION

This is a basic preview of what GitLab CI/CD is. Everything is Configuration as Code and it is specified on a file named .gitlab-ci.yml located at the root of our repository.

.gitlab-ci.yml is going to run trough different jobs inside a GitLab Runner

We can get more details on the oficial Documentation

KEYWORDS

Since it is configured on a yaml file, we need to know some keywords for the structure and instructions given to our jobs

Keywords	Short Description
`variables`	Used to list our variables
`stages`	Used to define the different stages on our pipeline
`image`	Define the image that `Docker` is going to use for the run
`before_script`	Define a set of commands to be executed before `script`
`script`	Set of commands to be executed
`services`	To specify any additional Docker images that your scripts require to run successfully
*Note:* For the complete list of `keywords`, click HERE

CI/CD VARIABLES AND SECRETS

Since we don’t want to hard code tokens, passwords or secrets. We can use CI/CD Variables. Which are under Settings -> CI/CD -> Variables.

Those can be called by using something like $SECRET_PASSWORD

EXAMPLE

Below we will se an example or use case. It is just a yaml file to be considered as a reference. It shows 3 stages test, build and deploy.

variables:
  IMAGE_NAME: nanajanashia/demo-app
  IMAGE_TAG: python-app-1.0

stages:
  - test
  - build
  - deploy

run_tests:
  stage: test
  image: python:3.9-slim-buster
  before_script:
    - apt-get update && apt-get install make
  script:
    - make test


build_image:
  stage: build
  image: docker:20.10.16
  services:
    - docker:20.10.16-dind
  variables:
    DOCKER_TLS_CERTDIR: "/certs"
  before_script:
    - docker login -u $REGISTRY_USER -p $REGISTRY_PASS
  script:
    - docker build -t $IMAGE_NAME:$IMAGE_TAG .
    - docker push $IMAGE_NAME:$IMAGE_TAG


deploy:
  stage: deploy
  before_script:
    - chmod 400 $SSH_KEY
  script:
    - ssh -o StrictHostKeyChecking=no -i $SSH_KEY root@161.35.223.117 "
        docker login -u $REGISTRY_USER -p $REGISTRY_PASS &&
        docker ps -aq | xargs docker stop | xargs docker rm &&
        docker run -d -p 5000:5000 $IMAGE_NAME:$IMAGE_TAG"

Note: Example based on this repo