timothy

timothy: a Node.js library for building Hadoop jobs in JS
=========================================================

Timothy's primary goal is to make The Yellow Elephant rich and famous.

Basic Example

``javascript
// require timothy
require('timothy')
// basic configuration for the job: hadoop conf, input, output, name, etc
.configure({
config: "./hadoop.xml",
input: "/test.txt",
output: "/processed_"+(new Date().getTime()),
name: "Timothy Word Count Example"
})
// map function: one (line) or two (key, value) arguments
.map(function(line){
var words = line.split(" ");
for(var i=0; i emit(words[i], 1); // emit is used to generate output
})
// reduce function: two arguments (key, value)
.reduce(function(word,counts){
emit(word, counts.length);
})
// run function, creates the job, uploads it and blocks until the
// the execution has finished
.run();
`

Testing in the local machine

`javascript
require('timothy')
.map(function(line){
var words = line.split(" ");
for(var i=0; i emit(words[i], 1);
})
.reduce(function(word,counts){
emit(word, counts.length);
})
// runLocal can be used instead of run to simulte the job execution
// from the command line
.runLocal("~/Desktop/test_input.txt");
`

Initialising a job

`javascript
require('timothy')
.configure({
config: "./hadoop.xml",
input: "/test.txt",
output: "/processed_"+(new Date().getTime()),
name: "Timothy Word Count Example"
})
// variables and functions added to the global object will be available
// in the map and reduce functions
.setup(function(){
global.x = 0;
global.inc = function() {
global.x = global.x + 1;
};
})
.map(function(line){
var words = line.split(" ");
for(var i=0; i inc();
emit(words[i], x);
}
})
.reduce(function(word,counts){
emit(word, counts.length);
})
.run();
`

Using node libraries

`javascript
require('timothy')
.configure({
config: "./hadoop.xml",
input: "/test.txt",
output: "/processed_"+(new Date().getTime()),
name: "Timothy Word Count Example"
})
// Libraries can be added using the same syntax as
// in a NPM package.json file
.dependencies({"node-uuid":"1.3.3"})
.setup(function(){
// libraries can be required in the setup function
global.uuid = require('node-uuid');
})
.map(function(line){
var words = line.split(" ");
for(var i=0; i emit(words[i], 1);
}
})
.reduce(function(word,counts){
emit(word, counts.length);
emit(uuid.v1(),"10000000");
})
.run();
``

Status and counters

Status and counters for the job can be updated using the updateStatus and updateCounter functions.