datamk / python-demoapp

Simple Python Flask web application designed for running in containers for demos

Python Flask - Demo Web Application

This is a simple Python Flask web application. The app provides system information and a realtime monitoring screen with dials showing CPU, memory, IO and process information.

The app has been designed with cloud native demos & containers in mind, in order to provide a real working application for deployment, something more than "hello-world" but with the minimum of pre-reqs. It is not intended as a complete example of a fully functioning architecture or complex software design.

Typical uses would be deployment to Kubernetes, demos of Docker, CI/CD (build pipelines are provided), deployment to cloud (Azure) monitoring, auto-scaling

Screenshot

Status

Live instances:

Building & Running Locally

Pre-reqs

• Be using Linux, WSL or MacOS, with bash, make etc
• Python 3.8+ - for running locally, linting, running tests etc
• Docker - for running as a container, or image build and push
• Azure CLI - for deployment to Azure

Clone the project to any directory where you do development work

git clone https://github.com/benc-uk/python-demoapp.git

Makefile

A standard GNU Make file is provided to help with running and building locally.

help                 💬 This help message
lint                 🔎 Lint & format, will not fix but sets exit code on error
lint-fix             📜 Lint & format, will try to fix errors and modify code
image                🔨 Build container image from Dockerfile
push                 📤 Push container image to registry
run                  🏃 Run the server locally using Python & Flask
deploy               🚀 Deploy to Azure Web App
undeploy             💀 Remove from Azure
test                 🎯 Unit tests for Flask app
test-report          🎯 Unit tests for Flask app (with report output)
test-api             🚦 Run integration API tests, server must be running
clean                🧹 Clean up project

Make file variables and default values, pass these in when calling make, e.g. make image IMAGE_REPO=blah/foo

Makefile Variable	Default
IMAGE_REG	ghcr.io
IMAGE_REPO	benc-uk/python-demoapp
IMAGE_TAG	latest
AZURE_RES_GROUP	temp-demoapps
AZURE_REGION	uksouth
AZURE_SITE_NAME	pythonapp-{git-sha}

The app runs under Flask and listens on port 5000 by default, this can be changed with the PORT environmental variable.

Containers

Public container image is available on GitHub Container Registry

Run in a container with:

docker run --rm -it -p 5000:5000 ghcr.io/benc-uk/python-demoapp:latest

Should you want to build your own container, use make image and the above variables to customise the name & tag.

Kubernetes

The app can easily be deployed to Kubernetes using Helm, see deploy/kubernetes/readme.md for details

GitHub Actions CI/CD

A working set of CI and CD release GitHub Actions workflows are provided .github/workflows/, automated builds are run in GitHub hosted runners

GitHub Actions

Running in Azure App Service (Linux)

If you want to deploy to an Azure Web App as a container (aka Linux Web App), a Bicep template is provided in the deploy directory

For a super quick deployment, use make deploy which will deploy to a resource group, temp-demoapps and use the git ref to create a unique site name

make deploy

Running in Azure App Service (Windows)

Just don't, it's awful