GitHub_Actions_introduction

I thought of making this repository just for people who are new to github actions, and want to get a quick flavour of the GitHub actions.

I personally think that GitHub actions are great and makes CI/CD for open source really easy to use. So Kudos to GitHub ! 👍

Detailed explanation of the repository workflow

We would be basically diving deep into the yml workflow file of our repository workflow_file

So, Lets start!

name: CI

we start the workflow specifying the name of the CI/CD workflow we want

on:
  push:
    branches:
      main
    paths-ignore:
      - '**/README.md'
  repository_dispatch:
  pull_request:

the on: keyword basically tells us when this particular workflow will be triggered in other words which events will trigger the actions. we can see here push and pull_request are the events on which the workflow will be triggered.

For manual trigger we use workflow_dispatch: for example:

 inputs:
        Name:
          description: 'Name you is triggering'
          required: true
          default: 'Admin'
        purpose:
          description: 'purpose for the build trigger'
          required: true
          default: 'check'

in workflow dispatch the inputs lets you provide some arguments with which you can fire the actions. Each input then has attributes like description, required (whether its mandatory or not), deafult.

To know about repository_dispatch please go to my another repository repository_dispatch_repo just to give you a brief its basically used to handle dependencies.

Now in each of the events you can provide branches option regarding for which branch the workflow will be triggered and also paths-ignore: which will ignore firing the actions if those files are changed.

jobs:
  # This workflow contains a single job called "build"
  deploy_and_test:
    # The type of runner that the job will run on
    runs-on: windows-latest
    strategy:
      matrix:
        python-version: [27, 38]

jobs basically is the part where we actually start configuring our environment and start writing the script for our Ci/CD pipeline. we can have multiple jobs in a single workflow and all the jobs are run parallely by default provided you are using runners provided by Github In this workflow we have a single job whose name is deploy_and_test.

runs-on basically tells you in which os you want to run your workflow in, Here we are using the windows-latest you can also use ubuntu-latest.

These runners are provided by GitHub itself to know more about runner click on the link GitHub hosted runners

strategy basically helps us to build us different test matrix for our worklow. In this workflow we have matrix where we are using both versions of python.

  steps:

    # checking out my code
    - name: Checkout
      uses: actions/checkout@v2

    # basically just getting the version number for which the build got triggered
    - name: Get version number
      id: get_version
      run: echo "::set-output name=version::$(cat VERSION)"

Each job has a list of steps which are executed sequentially. Now inside steps we do the tasts we wan to perform for the job. uses is used if you are using a task which is already supported by GitHub and you are just using the for you benefit, there are a lot of awesome actions which you can find in the Github Action Marketplace.

You can also write you own steps and use run attribute the run the command you want, for multiple commands we use run: |.

You can even check and condition and skip a step or task with if:. Please see the below sample:

name: check which files changed
if: github.event_name == 'push'
uses: jitterbit/get-changed-files@v1
id: change
with:
  format: space-delimited
  token: ${{ secrets.GITHUB_TOKEN }}

I have added some basic samples in the folder GitHub Action Samples. Have a look at it, will help you understand more.

Reference taken from workflow syntax. You can refer to this link for even more details.

Hope this helpes you !! ✨✨