Server side JavaScript: going all the way

Server side JavaScript:going all the way

#rejectjs 29.09.11

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#startups#akshell#ringojs

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Node.js

Ideal use cases

– Real time apps, infrastructure duct tape

Badly suited for

– CRUD, command line tools, CPU heavy loads

Easy to get started with

– Difficult to get into production

Akshell NarwhalJS

RingoJS Wakanda

GPSEE

v8cgi

ServerJS Fragmentation

Node.js CommonJS Wakanda RingoJS v8cgi Narwhal Common Node Flussperfd Akshell GPSEE0

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Sync vs. Async

“async style is kicking sync style's ass”

sync is “on top of” async – a higher level of abstraction

Sync vs. Async

function add(callback) { http.get(url1, function(response1) { var part1 = response1.data; http.get(url2, function(response2) { var part2 = response2.data; callback(part1 + part2); } }}

Sync vs. Async

http.get(url1).data + http.get(url2).data

Interoperability

Pure JavaScript modules run anywhere Templating, parsing, formatting, encoding

Anything doing I/O exposes sync or async API Defines the interface exposed by higher level

packages

CommonJS /1

Assert Console System/1.0

CommonJS /2

Binary/B

IO/A Filesystem/A JSGI 0.3 HTTP Client /A Sockets/A Subprocess

common-node

Implements synchronous CommonJS proposals using node-fibers

Traceur to support latest language features Bridges the gap between platforms, sync and

async

What it's good for?

everything!

What's it actually good for?

Business logic

– Lots of state, fine grained error handling CRUD

– Java, Rails, PHP, Python Command line tools Cross platform portability

On Threads & Fibers

“Threads suck”

- Brendan Eich, creator of JavaScript

“Fibers introduce interleaving hazards — Any function call can cause a yield and then your closure invariants *may be* broken.”

- Kris Kowal, creator of CommonJS/Modules

Concurrency in JavaScript

“You shouldn’t think that event-based concurrency eliminates synchronization, or shared memory, or anything other than preemption”

- Sam Tobin-Hochstadt, member of the Ecma TC39 committee on JavaScript

fibers /1

Co routine implementation using libcoro

Co-operative multitasking

Implicit synchronization

fibers /2

Not a fork or a hack of Node

No wrapper script required

V8 Context and 64KB stack per fiber

Will run on Windows

Node.js

process[ closure

closure

t →

RingoJS (0.8)

process thread stack

processthread stack

t →

Common Node (fibers)

processfiber stack

fiber stack[

t →

Comparison

Node.js Common Node RingoJS

Process Count Single Single Multiple

State Closure Fiber Stack Thread Stack

Multitasking User (co-op) Library (co-op) OS (pre-empt)

Memory Usage Low Low High

“Jitter” High High Low

Internals - sleep

exports.sleep = function(milliseconds) {

var fiber = Fiber.current;

setTimeout(function() {

fiber.run();

}, milliseconds);

yield();

};

Internals – HttpClient /1

var req = http.request(options, function(r) {

fiber.run(r);

});

req.on('error', function(error) {

fiber.run(error);

});

this.guts.body.forEach(function(block) {

req.write(block.buffer || block);

});

req.end();

Internals – HttpClient /2

var result = yield();

if(result instanceof Error)

throw new Error(result.message);

return {

status: result.statusCode,

headers: result.headers,

body: new Stream(result)

};

Internals - IO

// on 'data', 'end', 'error'

// pause when draining

var listeners = attach(this.stream);

var data = yield();

detach(this.stream, listeners);

Examples

JSGI

exports.app = function(request) {

return {

status: 200,

headers: {},

body: ['Hello World!']

// openRaw(module.filename)

};

};

Spawn & Sleep

exports.app = function(request) {

spawn(function() {

sleep(10000);

console.log('Hello Server!');

});

return {

status: 200,

headers: {},

body: ['Hello Client!']

};

};

HTTP Proxy

var HttpClient = require('httpclient').HttpClient;

exports.app = function(req) {

req.url = 'http://nodejs.org';

return new HttpClient(req).finish();

};

Twitter Streaming /1

var stream = new TextStream( new HttpClient({

method: 'POST',

url: '...',

headers: {}

body: ['track='+system.args[4]],

timeout: 10000

}).finish().body);

Twitter Streaming /2

var line;

while(true) {

line = stream.readLine();

if(!line.length) break;

if(line.length > 1) {

var message = JSON.parse(line);

console.log(message.text);

}

}

Telnet Chat /1

var socket = require('socket');

var server = new socket.Socket();

var clients = [], client;

server.bind('localhost', 23);

Telnet Chat /2

while(true) {

clients.push(client = server.accept().getStream());

spawn(function() { var stream = client, line;

while((line = stream.read(null)).length) {

clients.forEach(function(c) {

if(stream != c)

c.write(line);

});

}

clients.splice(clients.indexOf(stream), 1);

});

}

Demo

telnet 10.0.0.97

Benchmarksab -n 50000 -c 50

hello-world

exports.app = function() {

return {

status: 200,headers: {

'Content-Type': 'text/plain'},body: ['Hello World!\n']

};

};

string-alloc

exports.app = function(request) {

for( var i = 1; i <= 50; i++)

b.decodeToString("ascii");return {

status: 200,headers: {},body: [b]

};

};

parse-json

exports.app = function(request) {

JSON.parse(json);

return {

status: 200,headers: {},body: [json]

};

};

static-file

exports.app = function() {

return {

status: 200,

headers: {},

body: openRaw('../README.md')

};

};

set-timeout

exports.app = function() {

sleep(100);

return {

status: 200,

headers: {},

body: []

};

};

Throughput

hello-world string-alloc parse-json static-file set-timeout0

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Node.js

Common Node

RingoJS

SyncJS Fragmentation

Wakanda RingoJS v8cgi Narwhal Common Node Flussperfd Akshell GPSEE0

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Project Followers

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Road map

common-utils tests in separate project narhwal-mongodb fork hns/stick fork higher level packages (see project wiki)

Contributing

Google “common node”

github.com/olegp/common-node/

npm -g install common-node

Thank you!

@olegpodsechin