Awesome

Pando Handbook

Pando is a decentralized computing commandline tool that enables a stream of values to be processed collaboratively by volunteers on the web.

This handbook shows how to install and use pando, as well as how to reproduce experiments performed for submitted and published papers. If you obtained this handbook from a publication archive, it is actually a valid Git repository. It can therefore be updated to the latest version on GitHub (http://github.com/elavoie/pando-handbook) by doing git pull origin master.

Installation

(Suggested) Installing Node.js and NPM using NVM

Install NVM (other installation methods are explained https://github.com/creationix/nvm#installation:

curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.2/install.sh | bash

Install Node:

nvm install node

Install Pando

Latest stable version using NPM:

npm install -g pando-computing

Latest development version:

git clone https://github.com/elavoie/pando-computing
cd pando-computing
npm install && npm link

Quick Start

Save the following code in a file named square.js (or alternatively use the one provided in the pando-computing repository under examples/square.js) to define a computing function:

module.exports['/pando/1.0.0'] = function (x, cb) {
  setTimeout(function () {
    x = Number.parseInt(JSON.parse(x))
    var r = x * x
    cb(null, r)
  }, 1000)
}

Try squaring a list of numbers:

pando square.js 1 2 3 4 5 6 7 8 9 10

On startup, Pando should print on the standard error (your ip address will be different):

Serving volunteer code at http://192.168.16.194:5000
Serving monitoring page at http://192.168.16.194:5001

Then, Pando should print on the standard output the following numbers, one per second:

You can accelerate the computation by opening multiple browser tabs using the url for the volunteer code (http://192.168.16.194:5000 in the previous example).

You can ask pando to read the inputs from the standard input rather than as arguments:

seq 1 10 | pando square.js --stdin

And you can combine with other post-processing to keep only results that are even:

seq 1 10 | pando square.js --stdin | grep -e '.*[02468]$'

You can also use other npm packages, such as the debug package, in your computing function:

var debug = require('debug')
var log = debug('pando:examples:square')

module.exports['/pando/1.0.0'] = function (x, cb) {
  log('started processing ' + x)
  setTimeout(function () {
    x = Number.parseInt(JSON.parse(x))
    var r = x * x
    log('returning ' + r)
    cb(null, r)
  }, 1000)
}

You then simply have to install the packages used in the current working directory (ex: npm install debug). When loading the computing function on startup, Pando automatically packages it with all its dependencies with browserify so that it runs in the browser.

Supported Browsers

All Browsers that support WebRTC should be able to connect and execute volunteer code. So far we have succesfully used the latest versions of:

Application Examples

collatz - Test bignumber integers for the highest number of Collatz steps.
raytracer - Generate a GIF where each frame is generated via raytracing.
crypto-mining - Mine blocks using the proof-of-work algorithm of Bitcoin.
arxiv - Collaborative classification of Arxiv entries.
rlnetwork - Hyper-parameter optimization of a learning agent based on deep reinforcement learning.
photo-batch-processing - Processing of satellite images, with images transmitted over HTTP. Alternative implementations use DAT and WebTorrent.
random-testing - Random testing of concurrent executions of StreamLender, the core abstraction at the heart of Pando.

Related Packages

Pando is built with many packages that can be reused independently:

pull-lend - Lends one value at a time from a stream. Re-lends in case of errors.
pull-lend-stream - Continuously lends values to concurrent sub-streams. Transparent re-lending in case of failure of sub-streams.
pull-limit - Limits the total number of items inside a through pull-stream.
simple-updatable-website - Allows a client to remotely update the static filed served without restarting the server using a secret value established when the server was started.
webrtc-bootstrap - Bootstrap client and server to bootstrap WebRTC connections made with simple-peer
webrtc-bootstrap-server - Server for the webrtc-bootstrap client we
webrtc-tree-overlay - Dynamically maintain a tree overlay with WebRTC

Related Publications

Publication-Specific Instructions for Reproducing Experiments

These instructions are aimed at Artifact Evaluation Committee (AEC) members and other researchers and developers that wish to verify our claims as well as expand upon our work. Each publication is documented in its own directory, with all the data we obtained during our own experiments, the software and hardware configuration that were used, and the helper scripts we used. The specific version of Pando and the version of this handbook used are mentioned for each publication for replicability while allowing non-backward compatible changes to Pando in later versions.

Middleware 2019

Troubleshooting

electron-eval error: Electron process exited with code 1

You are probably trying to use pando on a remote server without a graphical environment. Use the --headless option.

Error: Could not start Xvfb: "Xvfb is not installed or is not in your $PATH"

You are probably using the --headless option without having started an instance of Xvfb beforehand. Start Xvfb:

Xvfb :99 -screen 0 1024x768x24; /dev/null 2>&1     &
export DISPLAY=':99.0';