Go & Vue.js - Demo Web Application

This is a simple web application with a Go server/backend and a Vue.js SPA (Single Page Application) frontend.

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

• The Frontend is a SPA written in Vue.js 3. It uses Bootstrap 5 and Font Awesome. In addition Gauge.js is used for the dials in the monitoring view
• The Go component is a Go HTTP server based on the std http package and using gopsutils for monitoring metrics, and Gorilla Mux for routing

Features:

• System status / information view
• Geolocated weather info (from OpenWeather API)
• Realtime monitoring and metric view
• Support for user authentication with Azure AD and MSAL
• Prometheus metrics
• API for generating CPU load, and allocating memory

Status

Live instance:

Repo Structure

/
├── frontend         Root of the Vue.js project
│   └── src          Vue.js source code
│   └── tests        Unit tests
├── deploy           Supporting files for Azure deployment etc
│   └── kubernetes   Instructions for Kubernetes deployment with Helm
├── server           Go backend server
│   └── cmd          Server main / exec
│   └── pkg          Supporting packages
├── build            Supporting build scripts and Dockerfile
└── test             API / integration tests

Server API

The Go server component performs two tasks

• Serve the Vue.js app to the user. As this is a SPA, this is static content, i.e. HTML, JS & CSS files and any images. Note. The Vue.js app needs to be 'built' before it can be served, this bundles everything up correctly.
• Provide a simple REST API for data to be displayed & rendered by the Vue.js app. This API is very simple currently has three routes:
  • GET /api/info - Returns system information and various properties as JSON
  • GET /api/monitor - Returns monitoring metrics for CPU, memory, disk and network. This data comes from the gopsutils library
  • GET /api/weather/{lat}/{long} - Returns weather data from OpenWeather API
  • GET /api/gc - Force the garbage collector to run
  • POST /api/alloc - Allocate a lump of memory, payload {"size":int}
  • POST /api/cpu - Force CPU load, payload {"seconds":int}

In addition to these application specific endpoints, the following REST operations are supported:

• GET /api/status - Status and information about the service
• GET /api/health - A health endpoint, returns HTTP 200 when OK
• GET /api/metrics - Returns low level system and HTTP performance metrics for scraping with Prometheus

Building & Running Locally

Pre-reqs

• Be using Linux, WSL or MacOS, with bash, make etc
• Node.js Go 1.16+ - for running locally, linting, running tests etc
• cosmtrek/air - if using make watch-server
• 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/vuego-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 BOTH components locally using Vue CLI and Go server backend
watch-server         👀 Run API server with hot reload file watcher, needs cosmtrek/air
watch-frontend       👀 Run frontend with hot reload file watcher
build-frontend       🧰 Build and bundle the frontend into dist
deploy               🚀 Deploy to Azure Container Apps
undeploy             💀 Remove from Azure
test                 🎯 Unit tests for server and frontend
test-report          🎯 Unit tests for server and frontend (with report output)
test-snapshot        📷 Update snapshots for frontend tests
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

• The server will listen on port 4000 by default, change this by setting the environmental variable PORT
• The server will ry to serve static content (i.e. bundled frontend) from the same directory as the server binary, change this by setting the environmental variable CONTENT_DIR
• The frontend will use /api as the API endpoint, when working locally VUE_APP_API_ENDPOINT is set and overrides this to be http://localhost:4000/api

Containers

Public container image is available on GitHub Container Registry

Run in a container with:

docker run --rm -it -p 4000:4000 ghcr.io/benc-uk/vuego-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

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

Config

Environmental variables

• WEATHER_API_KEY - Enable the weather feature with a OpenWeather API key
• PORT - Port to listen on (default: 4000)
• CONTENT_DIR - Directory to serve static content from (default: .)
• AUTH_CLIENT_ID - Set to a Azure AD registered app if you wish to enable the optional user sign-in feature

Optional User Sign-In Feature

The application can be configured with an optional user sign-in feature which uses Azure Active Directory as an identity platform. This uses wrapper & helper libraries from https://github.com/benc-uk/msal-graph-vue

If you wish to enable this, carry out the following steps:

• Register an application with Azure AD, see these steps
• Set the environmental variable AUTH_CLIENT_ID on the Go server, with the value of the client id. This can be done in the .env file if working locally.
• Optional when testing/debugging the Vue.js SPA without the Go server, you can place the client-id in .env.development under the value VUE_APP_AUTH_CLIENT_ID

GitHub Actions CI/CD

A set of GitHub Actions workflows are included for CI / CD. Automated builds for PRs are run in GitHub hosted runners validating the code (linting and tests) and building dev images. When code is merged into master, then automated deployment to AKS is done using Helm.

Updates