DistributedRails

Distributes tasks to multiple browsers

Inspired by projects like folding@home and SETI@home, this is a plugin for Rails that allows the server to distribute tasks to its clients (browsers). This is best suited for highly parallelizeable tasks such as monte-carlo simulations or other embarassingly parallel problems.

Original (read: deprecated) project: ciniglio/distributed

Usage

Install with bundler

`gem 'distributed_rails'

Then in your routes.rb:

mount DistributedRails::Engine, :at => '/tasks'

Finally, in whichever template you'd like this to run from

e.g. `layouts/application.html.erb`

Add the line <%= javascript_include_tag "distributed_rails/application" %>

Now we're ready to get cooking!

Provide tasks.js files in app/tasks
task*.js must define var nextTask = main_function_name
The result of main_function_name will be saved in the db

Notes

Verification

Already completed tasks will run again on a new machine and the results will be compared (about 10% of the time). This gives some additional confidence in the results, but is by no means a security guarantee.

Some tasks (e.g. random generations) are not well suited for verification. For these tasks, the rake tasksjs:repeated command takes an additional argument to omit verification.

Rakefile

A Rakefile has been provided to make some common tasks easier. The namespace is tasksjs.

Note: For rake operations that add tasks to the database, rake will also look for a parameters file parameters_task*.txt in the same location, and will use parameters on a single line. See more at parameters

rake tasksjs:init will clear all tasks from the database, then go through all the tasks in app/tasks and add them to the database
rake tasksjs:repeated will take an argument num and add all the tasks in app/tasks num times.
as noted above rake tasksjs:repeated will take an additional argument to disable verification. If you want verification to be disabled, you should pass "true".

Parameters

The parameters_task*.txt file is expected to have all the needed comma separated parameters on one line. This will then be applied to the function in task*.txt, once for every line.

A parameters_task*.txt like the following:

0, "james", "sally"
5, "john", "jerry"

will result in two tasks being added to the queue:

task*.js with args 0, "james", "sally"
task*.js with args 5, "john", "jerry"

Initial Goals

browsers execute arbitrary tasks and return results to browser
server manages queue from db
things are added to queue only by the server (clients adding tasks is a non-goal for now)