Example Voting App

Getting started

Download Docker. If you are on Mac or Windows, Docker Compose will be automatically installed. On Linux, make sure you have the latest version of Compose. If you're using Docker for Windows on Windows 10 pro or later, you must also switch to Linux containers.

Run in this directory:

docker-compose up

The app will be running at http://localhost:5000, and the results will be at http://localhost:5001.

Alternately, if you want to run it on a Docker Swarm, first make sure you have a swarm. If you don't, run:

docker swarm init

Once you have your swarm, in this directory run:

docker stack deploy --compose-file docker-stack.yml vote

Run the app in Kubernetes

The folder k8s-specifications contains the yaml specifications of the Voting App's services.

Run the following command to create the deployments and services objects:

$ kubectl create -f k8s-specifications/
deployment "db" created
service "db" created
deployment "redis" created
service "redis" created
deployment "result" created
service "result" created
deployment "vote" created
service "vote" created
deployment "worker" created

The vote interface is then available on port 31000 on each host of the cluster, the result one is available on port 31001.

Architecture

• A Python webapp which lets you vote between two options
• A Redis queue which collects new votes
• A .NET worker which consumes votes and stores them in…
• A Postgres database backed by a Docker volume
• A Node.js webapp which shows the results of the voting in real time

Note

The voting application only accepts one vote per client. It does not register votes if a vote has already been submitted from a client.