Let’s build a

Ruby Application Server

Team WebROaR

vineet.tyagi@webroar.in

How do ‘you’ visualize an ‘Application Server’?

Or it could be like this …

Let’s define the specs

Run all Ruby Web Applications

Rack Compliant

And also ..

Provide run time performance numbers of

the deployed applications

Report exceptions

Love to have …

Maximum performance

Simplicity

Let’s start building it …

What does the server need to do?

Accept client connection

Parse HTTP request

Hand it over to the ruby web framework

Send its response back to the client

Network Server Design

Evented vs Threaded

Event Based I/O Libraries

libev (Written in C)

EventMachine (Ruby Module + Extension

Library written in C++)

HTTP Parser

Mongrel’s Ragel Based Parser (written in C)

is ‘awesome’

Accept client connection

Parse HTTP request

Hand it over to the ruby web

framework

Send its response back to the

client

libev/EventMachine

Mongrel’s Ragel based Parser

?

libev/EventMachine

OptionsServer Tasks

More awesomeness - Libebb

Lightweight HTTP Library for C

libev + Mongrel’s Ragel based Parser

Implements HTTP/1.1 Grammar

Supports persistent, pipelined & chunked requests

Rejects invalid and malicious requests

Accept client connection

Parse HTTP request

Hand it over to the ruby web

framework

Send its response back to the

client

libebb

libebb

?

libebb

OptionsServer Tasks

Embedded Ruby Interpreter

#include <ruby.h>

int main(int argc, char **argv) {int state = 0;

ruby_init();

ruby_script("c-executable-name");

ruby_init_loadpath();

//Can use rb_gv_set() or rb_iv_set() methods to pass parameters to ruby land

rb_protect(RUBY_METHOD_FUNC(rb_require), (VALUE)"path-to-ruby-script", &state);

if(state != 0) {

// Exception Handling Code

return -1;

}

//Can use rub_funcall() to invoke methods in the ruby land

return 0;

}

Accept client connection

Parse HTTP request

Hand it over to the ruby web

framework

Send its response back to the

client

libebb

libebb

Embedded Ruby Interpreter

libebb

OptionsServer Tasks

Hola, we got a basic application server ready!

The Server – First Cut

libebb

Ruby Interpreter

Rack Web Application

Response

HTTP Request

But it only processes one request at a time ..

Let’s split up the server code and create more

ruby processing instances & static file

renderers (‘workers’)

The more powerful server version …

Response

HTTP Request

libebb libev

Head

Ruby Interpreter

Rack Web Applicationlibev

Worker #1

Ruby Interpreter

Rack Web Applicationlibev

Worker #2

Static Files Rendererlibev

Worker #n

Asynchronous Non-blocking I/O

SCGI

Server can handle (very) high load with this

architecture

Let’s capture data for each request being

processed …

The Server – Current Architecture

Response

HTTP Request

Head

Worker #n

Worker #1

DB

Message Queue

Request Analytics Data &

Exception Notifications

Analyzer DaemonAdmin Panel

Conf File

Hurray, we can write all the new advanced

features in our favorite language ..

Ruby makes life easier for …

Instrumentation

Messaging

Analyzer

Interacting with the Database

Admin Panel (It’s a Rails Application!)

Takeaways

Use the best tool for the job

C – Network I/O, Ruby – Advanced Features

Do not reinvent the wheel. Use tried and

tested libraries

Check it out

WebROaR – http://webroar.in

Photo Credits

All photographs used in this presentation are licensed under Creative Commons

Slide 3 – Stone House By Jsome1

Slide 5, 34 – Our House By Lee Coursey

Slide 11 – Willow Lane Construction By Lee Coursey

Slide 22 – Construction of our House – Framing By Lee Coursey

Slide 27 – Dead Lift By scarndp

Slide 29 – Willow Lane Construction By Lee Coursey

Slide 35 – Very Happy By Chris Winters

Slide 38 – Lion By auburnxc

More Questions?