Raterlimiter

An Erlang application to limit rate of requests. Initially developed to limit requests to Mochiweb server.

Installation

Just udate your rebar.config file with

    {deps, [
      {raterlimiter, ".*",
       {git, "git://github.com/Gromina/raterlimiter.git", "master"}}
    ]}.

Raterlimiter needs 2 application parameters -

timeout - Timeout to delete unused bucket (milliseconds)
cleanup_rate - How often to run clenup funciton (milliseconds)

If you need to change them, update your app.config with

   {raterlimiter, [
     {timeout, 300000},      % bucket maximum lifetime (5 min)
     {cleanup_rate, 10000}   % cleanup every X milliseconds (every 10 secs)
   ]}

Usage

Once you start the application with

application:start(raterlimiter).

or with command line

erl -s raterlimiter

you can start rate limiting any of your tasks.

raterlimiter:check_rate(RequestID, BucketTimeFrame, RequestsLimit)

which returns either {ok, continue} or {fail, Limit}

RequestId - Your task, request or client ID. In case of Mochiweb it is probably mochiweb_request:get(peer)
BucketTimeFrame - Time frame to apply limit, in milliseconds. 1000 means change bucket every second
RequestsLimit - Maximum number of requests allowed to do within one bucket

Author

Alexander Sorokin gromina@gmail.com, http://alexsorokin.ru