@subfuzion/database

This is a simple database library package that provides the ability to save and tally votes to a MongoDB database. It uses the MongoDB Node Driver.

Votes are stored as documents in the votes collection of the voting database.

Testing

The easiest way is to test using Docker Compose.

The following will build an image for running the tests under test/test.js and then start the environment declared in ./docker-compose.test.yml.

$ docker compose -f ./docker-compose.test.yml run sut

If you make changes to any of the Node.js sources, rebuild the test image with the following command:

$ docker compose -f ./docker-compose.test.yml build

To view logs, run:

$ docker compose -f ./docker-compose.test.yml logs

When finished with tests, run:

$ docker-compose -f ./docker-compose.test.yml down

To delete the generated image:

$ docker images rm database_sut

Testing without Docker Compose

MongoDB needs to be available before running tests. The tests default to port the standard MongoDB port 27017 on localhost, but host and port can be overridden by setting HOST and PORT environment variables.

If you have Docker installed, you can easily start MongoDB with the default values by running the following command:

$ docker run -d -p 27017:27017 --name mongodb mongodb

This will run a MongoDB container named mongodb in the background with port 27017 on your system mapped to the exposed port 27017 in the container.

To run the tests, enter the following:

$ npm test

When finished, you can remove the running container from your system with:

$ docker rm -f mongodb

Using the @subfuzion/database package

Add the dependency to your package:

npm:

$ npm install @subfuzion/database

yarn:

$ yarn add @subfuzion/database

Create a Database object

Require the package in your module:

const Database = require('@subfuzion/database').Database;

Create a new instance

var db = new Database([options])

options is an optional object that defaults to the values in lib/defaults.js for any missing properties.

const config = {
  host: 'database',
  port: 27017,
  db: 'voting'
};

There is a Database helper static method that will create the configuration that can be overridden by environment variables:

let defaults = {};
// explicit defaults will override environment variables, environment overrides internal defaults
let config = Database.createStdConfig(defaults);
let db = new Database(config);
await db.connect();

If any of the following environment variables are defined, then the values will override the default values. Any values explicitly supplied in the config object will override the environment.

DATABASE_URI - valid mongo connection URI
otherwise:
  DATABASE_HOST - hostname for the mongo server
  DATABASE_PORT - port that mongo is listening on
DATABASE_NAME

Storing votes

var db = new Database([options])
let vote = { vote: 'a' } // valid values are 'a' or 'b'
await db.updateVote(vote)
// when finished with the database
await db.close()

Tallying votes

var db = new Database([options])
let tally = await db.tallyVotes()
// tally is an object: { a: <number>, b: <number> }
// when finished with the database
await db.close()

Closing Connections

You should close the database connection when finished.

await db.close()