Entry for the League of Legends API Challenge 2015
Switch branches/tags
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.


For What It's URF

Live Site: For What It's URF

Created for Riot Games API Challenge, what started as a fantasy scoring application (hence the name 'urfantasy') ended up turning into a data exploration application. Rather than using strictly familiar technologies, my duo queue partner for this project, dbanksdesign, and I also incorporated new/trendy stuff (at least to us) such as Docker, ReactJS, D3.js, and Postgres for JSON persistence. I plan to write a retrospective of this development experience on my blog.

The goal of our application is to provide interesting information about URF without denying our users the experience to be their own explorers. We feel that once users get accustomed to the treemap interface, they can delight in their discoveries and have fun reviewing the URF data. As a project, the code can be a valuable resource to anyone trying to learn how to import, transform, and present data by interacting with queues, the database, and the frontend stack. As for the code itself, we don't recommend anyone using it as a template (gets bad towards deadline), but would probably best serve as a reference for any of the technologies we're using.

Tech Stack

  • Ruby 2.2.1
  • Rails 4.2 (JSON API)
  • Postgres (persistence, jsonb!)
  • Sidekiq (queueing)
  • Redis (backed Sidekiq)
  • ReactJS, Backbone, Semantic-UI, D3.js (frontend)
  • Docker (dev/prod environment)
  • Puma (rails server)
  • Nginx (reverse proxy)
  • memcached (caching)


While it was available, the Riot API Challenge endpoint provided a randomized list of match ids in 5 minute intervals for each region. The endpoint required the beginTime parameter in Unix epoch time to the nearest 5 minutes. With a simple queuing setup, the import process was able to fetch over 490,000 matches as well as perform aggregations on fields of interest.

Zilean, the Scheduler

Since the import tools were still under development after the endpoint was made available, a Sidekiq queue was used to schedule jobs for a worker named Zilean matching every possible beginTime. I used 1427866200..1429340400 (contest end date, but URF ended before that) in 300 second intervals with a 600 second offset (in case Riot was slow). This was, in my mind, the easiest way reconcile everything I missed to when it finally catches up.

Nunu, Challenge Endpoint Consumer

When a Zilean job runs, it delegates the consuming of the the challenge endpoint for each region to Nunu, and feasting of the match ids response to Chogath. All aspects of the import process were developed with idempotency in mind, so if Zilean had to re-run (perhaps due to implementation changes), checks are made between Nunu and Chogath to ensure nothing gets inserted twice.

Chogath, Match Endpoint Feaster

Chogath iterates through the list of match IDs provided by Nunu and feasts on the JSON responses. The requests used to be handled one by one, which was fine at first (or with a dev API key), but was somewhat inefficient. The solution was to modify my Ruby gem Taric to handle parallel HTTP requests, so that simultaneous requests can be made, and Chogath could batch insert the responses into a jsonb type column in Postgres.

Bard, the Collector

To minimize database load, a worker named Bard was created and scheduled to aggregate an hours worth of data on an hourly basis. Like Zilean, jobs were scheduled to cover the entire spectrum of the challenge endpoint's existence. Unlike Nunu and Chogath, Bard's job is not idempotent since aggregation is a 'destructive' process, and there's a chance that new matches that weren't available at request time (e.g. KR endpoint is down) become available in a rerun of Zilean.


ReactJS touts itself as being the V of MVC, and since neither of us were familiar with one-way data binding via Flux, Danny settled on Backbone for the routing aspect. He was able to write React components in CoffeeScript thanks to a gem called sprockets-coffee-react. Once he was familiar with React component development with Backbone, we agreed on the single page application approach. With only a week left to finish the project, we decided the fantasy application was no longer feasible (plus URF ended), but since we had a lot of data, we decided a data exploration application would have a better shot at being completed in time. Danny had prior experience with D3.js and suggested a treemap overview of the aggregated data. The SQL queries were actually pretty fast, but I stored the results in memcached anyway to keep the site running smoothly. Danny also used Semantic-UI, which is a semantic i.e. natural language based components framework.


I have a small VPS running on Digital Ocean, and while our application is light enough to run off Heroku, I wanted to practice running services in Docker. I was able to create a separate docker-compose configuration for the production environment that gets linked to another docker-compose group of containers that has nginx. Setting up the reverse proxy to the rails server, puma, was pretty easy, and will be documented in my blog in the near future.

Installation (URF Mode)

This repository contains a Dockerfile to build the image the web app will run in, and a docker-compose.yml file to link the dependencies:

  • Rails 4.2
  • PostgreSQL 9.4
  • Redis 2.8
  • Sidekiq


Get an API key from the Riot Games Developer site.

Install Docker and Docker Compose

Setup .env file

From the project's root folder, copy the .env.template file to .env and change as necessary. Be sure to define your RIOT_API_KEY.


From the project's root folder, build:

docker-compose build

After building, run it (ctrl+c to exit):

docker-compose up

Open a separate terminal instance and run migrations:

docker-compose run app rake db:create
docker-compose run app rake db:migrate

Visit http://localhost:3000 to see if it's running.

Import Process

# queuing jobs
docker-compose run app rake urfantasy:queue_all

# starting workers
docker-compose -f docker-compose-zilean up

Aggregator Process

# queuing jobs
docker-compose run app rake urfantasy:aggregate

# starting workers
docker-compose -f docker-compose-bard up

Useful Commands

# console
docker exec -it urfantasy_app_1 rails c

# migrations
docker exec -it urfantasy_app_1 rake db:migrate

# postgres
docker exec -it urfantasy_postgres_1 psql -U postgres urfantasy_dev