Example Voting App ========= [](https://github.com/BretFisher/example-voting-app/actions/workflows/call-super-linter.yaml) [](https://github.com/BretFisher/example-voting-app/actions/workflows/call-docker-build-result.yaml) [](https://github.com/BretFisher/example-voting-app/actions/workflows/call-docker-build-vote.yaml) [](https://github.com/BretFisher/example-voting-app/actions/workflows/call-docker-build-worker.yaml) A simple distributed application running across multiple Docker containers. Getting started --------------- Download [Docker Desktop](https://www.docker.com/products/docker-desktop) for Mac or Windows. [Docker Compose](https://docs.docker.com/compose) will be automatically installed. On Linux, make sure you have the latest version of [Compose](https://docs.docker.com/compose/install/). Linux Containers ---------------- The Linux stack uses Python, Node.js, and Java, with Redis for messaging and Postgres for storage. Run in this directory: ```shell docker-compose up ``` The app will be running at [http://localhost:5000](http://localhost:5000), and the results will be at [http://localhost:5001](http://localhost:5001). Alternately, if you want to run it on a [Docker Swarm](https://docs.docker.com/engine/swarm/), first make sure you have a swarm. If you don't, run: ```shell docker swarm init ``` Once you have your swarm, in this directory run: ```shell docker stack deploy --compose-file docker-stack.yml vote ``` Run the app in Kubernetes ------------------------- The folder `k8s-manifest` contains the resources of the Voting App's services. First create the vote namespace ```shell kubectl create namespace vote ``` Run the following command to create the deployments and services objects: ```shell $ kubectl apply -f k8s-manifests/ 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 frontend web app in [Python](/vote) which lets you vote between two options * A [Redis](https://hub.docker.com/_/redis/) queue which collects new votes * A [Java](/worker/src/main) worker which consumes votes and stores them in… * A [Postgres](https://hub.docker.com/_/postgres/) database backed by a Docker volume * A [Node.js](/result) webapp which shows the results of the voting in real time Notes ----- The voting application only accepts one vote per client. It does not register votes if a vote has already been submitted from a client. This isn't an example of a properly architected perfectly designed distributed app... it's just a simple example of the various types of pieces and languages you might see (queues, persistent data, etc), and how to deal with them in Docker at a basic level.