A tool called act makes this possible. It allows us to test run github actions locally. This can be useful for a quicker feedback loop than setting up a test github repository. Also in cases, setting up a testing repository may not be feasible i.e testing github organization or enterprise specigic things. Act won't let you test everything org specific but you can get pretty close

Getting started

Pre-requisites:

• Docker
• act

brew install act

Setting up your app to be Dockerized

To create a simple flask app for example (This can be anything):

Create a new directory and create a file in it i.e app.py

pip install flask

from flask import Flask

app = Flask(__name__)


@app.route("/")
def hello_world():
    return "Hello from flask"

if __name__ == "__main__":
    app.run(debug=True)

pip freeze > requirements.txt

Quick Dockerfile

FROM python:3.11.1-slim-buster

WORKDIR /src

COPY requirements.txt requirements.txt

RUN pip3 install -r requirements.txt

COPY . .

CMD [ "python3", "-m" , "flask", "run", "--host=0.0.0.0"]

Creating local docker registry or use the github container registry (ghcr)

docker run -d -p 5001:5000 --restart=always --name registry registry:2

Now we need a file to define the structure of our github ci action

This usually lives at .github/workflows/test-ci.yaml at the project root

Example CI yaml file w/ docker build-and-push plugin

name: Build and deploy new app image

on:
    push:
        branches:
        - master

jobs:
    push-app-image:
        if: github.event_name == 'push'
        name: push-app-image
        runs-on: ubuntu-latest
        steps:
        - uses: actions/checkout@v3
            with:
            fetch-depth: 0
        - run: echo "::set-output name=date::$(date +'%FT%H%M%SZ')"
            id: date
        - uses: docker/login-action@v1
            with:
            registry: local-registry
            username:
            password:
        - uses: docker/build-push-action@v2
            with:
            context: .
            push: true
            tags: |
                localhost:5001/${{ github.event.repository.name }}:${{ steps.date.outputs.date }}
                localhost:5001/${{ github.event.repository.name }}:latest
        - uses: docker/build-push-action@v2
            with:
            context: .
            file: ./Another.Dockerfile
            push: true
            tags : |
                localhost:5001/${{ github.event.repository.name }}-admin:${{ steps.date.outputs.date }}
                localhost:5001/${{ github.event.repository.name }}-admin:latest

So, the folder structure should now look like this:

flask-app:
    | - .github:
        | - workflows:
            | - test-ci.yaml
    | - app.py
    | - Dockerfile
    | - requirements.txt
    | - .git
    | - .gitignore

Now we can run the github action with act:

act -w .github/workflows/test.yaml

Note: You'll need to add --container-architecture linux/amd64 if you're on M1 Mac