/ostracon

Erlang library for realtime vote collection

Primary LanguageMakefile

Ostracon

This submission consists of two examples, each of which has its own copy of all Ostracon files, as well as client side code. For a more detailed expanation of the how Ostracon's modules interact, see project-final-report.pdf.

Team name: Ostracon (a.k.a. FunkMasterPrimeDeluxe)

  • Louis Rassaby
  • Scott Jacobson
  • Daniel Kim
  • Jeremy Max Goldman

Fork us on Github! https://github.com/lrassaby/ostracon

###Dependencies (installed automatically during the build process):

  • Cowboy for HTTP connections
    • Cowlib
    • Ranch
  • Jiffy for JSON creation Built using the relx package manager.

###Build instructions

  1. cd to the root directory of the submission
  2. type "Make intro" to build and run the intro demo on localhost:8081
  3. type "Make professors" to build and run "Let's Have Some Funding" on localhost:8080 During the build process, relx will grab dependencies from Github. If you're having trouble with dependencies, cd to introdemo or professors and remove the deps directory. Then try the the build process again.

###File structure for significant components There are other components, but most are for packaging the app for distribution with relx. |- Makefile (directions above) |- Design (contains previous designs) |- introdemo (contains the intro demo with graphs and presentation) |- priv (contains static assets for the front end) |- index.html |- favicon.ico (not really important, but 90s style favicon) |- assets |- js |- index.js (contains application-specific code) |- ostracon.js (contains Ostracon's front end library) |- src (contains the ostracon library, plus the callback module) |- callback_module.erl |- ostracon.app.src |- ostracon_app.erl |- ostracon_collector.erl |- ostracon_handler.erl |- ostracon_sup.erl |- professors (contains the multiplayer game) |- priv (contains static assets for the front end) |- index.html |- favicon.ico (not really important, but 90s style favicon) |- assets |- js |- index.js (contains application-specific code) |- ostracon.js (contains Ostracon's front end library) |- src (contains the ostracon library, plus the callback module) |- callback_module.erl |- ostracon.app.src |- ostracon_app.erl |- ostracon_collector.erl |- ostracon_handler.erl |- ostracon_sup.erl ###File descriptions

Ostracon.js This is the front end JavaScript module that connects with application-specific front end code. It sends votes to the handler and receives the updated state from the handler to give to the client. The Ostracon front end library exports the following functions:

    ostracon.start();
    ostracon.getState();
    ostracon.pushVote(vote);
    ostracon.requestState();

ostracon_app.erl This module starts off the voting procedure by creating the Vote ETS and State ETS, then initiates the collector module. It also establishes a link with a supervisor. Finally, it sets up Cowboy to spawn instances of Ostracon Handler upon connection requests.

ostracon_sup.erl This module monitors Ostracon App for failure and has a one-for-one restart policy with it.

ostracon_collector.erl The collector gathers votes from the Vote ETS every cycle and computes a vote histogram to send to the callback module. The length of each cycle is determined by the Callback Module.

ostracon_handler.erl This module communicates with the client via WebSocket; it receives the client's vote to record in the Vote ETS and sends the updated state to the client. Ostracon Handler also sends the current state to any new client that joins in the middle.

callback_module.erl This is the back end written by the application developer using Erlang. It determines how each vote should affect state, writing state updates directly to the State ETS.

Front end code Application-specific front end logic that communicates with the back end using Ostracon.js.