tHE BRIGHT SIDE OF THE MOON

A Lua lang intro

(FOR RUBYSTS)

WHO AM I ?

Sebastián Moreno

R&D @ inConcert

@kernelp4nic

And Lua is?

Lua is a powerful, fast, lightweight, embeddable scripting language.

Lua was created in 1993 by Roberto Ierusalimschy, Luiz Henrique de Figueiredo, and Waldemar Celes, members of the Computer Graphics Technology Group (Tecgraf) at the Pontifical Catholic University of Rio de Janeiro, in Brazil.

Why lua?

Why Lua is so special?

Lua is Robust

Lua is Portable & Embeddable

Lua is Fast

If you need more speed, try LuaJIT http://luajit.org/

Lua is Small as hell.

Source code and docs takes 246K compressed and 960K uncompressed. The source contains around 20000 lines of C.

That makes it perfect

to fit inside other projects

Russian power

NGINX + LUA


    
    lua_package_path '/foo/bar/?.lua;/blah/?.lua;;';
    lua_package_cpath '/bar/baz/?.so;/blah/blah/?.so;;';
 
    server {
        location / {
           lua_need_request_body on;
 
           client_max_body_size 100k;
           client_body_buffer_size 100k;
 
           access_by_lua '
               -- check the client IP address is in our black list
               if ngx.var.remote_addr == "132.5.72.3" then
                   ngx.exit(ngx.HTTP_FORBIDDEN)
               end
 
               -- check if the request body contains bad words
               if ngx.var.request_body and
                        string.match(ngx.var.request_body, "fsck")
               then
                   return ngx.redirect("/terms_of_use.html")
               end
 
               -- tests passed
           ';
 
           # proxy_pass/fastcgi_pass/etc settings
        }
    }

REDIS 2.6

Redis - eVAL & EVALSHA & Script load

redis 127.0.0.1:6379> SCRIPT LOAD "return 'hello meetup'"
=> "cc834f607fb5249665c1f99c4daa71903768c575"
 
redis 127.0.0.1:6379> EVALSHA cc834f607fb5249665c1f99c4daa71903768c575 0
=> "hello meetup"

redis 127.0.0.1:6379> eval "return redis.call('set','foo','bar')" 0
OK
redis 127.0.0.1:6379> keys *
1) "foo"
redis 127.0.0.1:6379> eval "return redis.call('get','foo')" 0
"bar"

REDIS - Available libraries

base lib
table lib
string lib
math lib
debug lib
cjson lib
cmsgpack lib

Used in many games too.

World Of Warcraft

League of Legends

Minecraft

Every company may have a use for it!

Lua @ inConcert

LuaNode (Async IO for Lua)

redis-luanode (Redis client for LuaNode)

Route66 (simple URL routing for LuaNode)

TwitterProxy (Written in LuaNode)

LuaCassandra

inConcert Web Handler (HTTP 1.1 server that runs Lua)

JSON4Lua

FeelingsDetector (Detects feelings inside text)

luaoauth (Oauth library)

Nozzle (Write filters and chain them together into pipeline)

Extensible Middleware Scripts (InteractionRouter)

Every REST API around

A basic luanode example


    local http = require('luanode.http')

    http.createServer(function(self, request, response)
        response:writeHead(200, {["Content-Type"] = "text/plain"})
        response:finish("Hello Ruby Meetup!")
    end):listen(8080)

    console.log('Server running at http://127.0.0.1:8080/')

    process:loop()

http://studio.zerobrane.com/

There is a debugger too, if you need it ;-)

Code me maybe?

You can apply Lua philosophy to your actual code.

You don't need to drop your current lang,

you just need to find the perfect time to use a tool.

References

The Bright Side Of The Moon (rb)

By kernelp4nic

The Bright Side Of The Moon (rb)

A lua lang intro for rubysts

1,167

kernelp4nic

kernelp4nic