This is an alpha release. We are using it internally in production, but the API and organizational structure are subject to change. Comments and suggestions are much appreciated.

Introduction

Patavi is a distributed system for exposing R scripts as web services (through WAMP RPC). It was created out of the need to run potentially very long running R scripts in a web browser while providing an interface to see the status updates. We currently use it to do Multi Criteria Decision Analysis (MCDA), see our demo. It is written in Clojure.

Alternatives

If you are looking for just a web-based interactive R environment checkout RStudio Shiny. If you just want to expose R scripts as HTTP see FastRWeb or one of the many other options.

Usage

Start the server with lein run in the server folder then start one or more workers with lein run. You can provide the method name and file in the options (run lein --help for details).

The R script takes exactly one argument params which is the de-serialized JSON (through RJSONIO). The following script emulates a long running process:

slow <- function(params) {
  N <- 100;
  x <- abs(rnorm(N, 0.001, 0.05))
  for(i in as.single(1:N)) {
    update(i); # send an out of band progress update
    Sys.sleep(x[[i]])
  }

  # The plot will be converted to base64 (url encoded)
  save.plot(function() hist(x), "duration", type="png")

  params
}

The server is exposed as WAMP which can be accessed with, for example, Autobahn (see client folder for an example using AngularJS).

Installation

To manually set up an environment you'll need the following set-up and configured:

• R (with RJSONIO, RServe(>= 1.7) and for image support Cairo and base64enc)
• Java (>= 1.7)
• ZeroMQ (preferably >= 3.0)
• Leiningen (> 2.0)

clone the repository and lein install the common folder. Then start the server and worker by running lein run, see lein run -- --help for options

Performance

Using criterium to benchmark an echo service (one worker) the following results were obtained:

Evaluation count : 3480 in 60 samples of 58 calls.

Name	Measurement
Execution time mean	16.029490 ms
Execution time std-deviation	2.065263 ms
Execution time lower quantile	12.122101 ms ( 2.5%)
Execution time upper quantile	19.261436 ms (97.5%)
Overhead used	1.058769 ns

Note, however, that the 16 ms is a severe underestimate since it does not take into account network latency or the overhead of serializing / deserializing the input data.

Licence

Copyright 2013 Joel Kuiper and other contributors http://patavi.com/

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.