Modulos Nginx usando Lua Rachad Honein

NGINX

¤  HTTP server with High Performance

¤  Events based architecture

¤  Small footprint on memory and processing

¤  Declarative Configuration

¤  Like Apache natively extensible through C modules

Market Share

Nginx Configuration Directives

1  location /hello { 2  set_unescape_uri $name $arg_name; 3  set_if_empty $name "Anonymous"; 4  echo "Hello, $name!"; 5  }

Lua

Lua

Lua

¤  Open-Source (MIT License)

¤  Brazilian scripting language created in1993 - PUC-Rio

¤  Interpreted Language

¤  Modular Language / Embedded / Portable

¤  Extremely fast scripting language

¤  Dynamically typed

¤  Functional language

¤  Prototype based language => Object Oriented

¤  Looks and feels like Javascript

Who uses Lua? ¤  Very popular in Games Engines and much more

¤  World of Warcraft ¤  Angry Birds ¤  Netflix ¤  Globo ¤  Cloudflare ¤  Redis ¤  Adobe Photoshop Lightroom ¤  Apache HTTP Server ¤  Apache Traffic Server ¤  Firefox ¤  MediaWiki ¤  MySQL Proxy ¤  MySQL Workbench ¤  PL/Lua for PostgreSQL

¤  Cisco ¤  Internet of things https://sites.google.com/site/marbux/home/where-lua-is-used

Lua

¤  Fast language:

Comparison with other scripting languages

Lua Nginx module

¤  The Power of Lua in Nginx

¤  "Light threads" based on Lua coroutines

¤  Acts on all phases inside the Nginx process ¤  Rewrite Phase ¤  Access Phase ¤  Content Phase ¤  Log Phase

¤  Exposes all the Nginx environment to Lua via an API http://wiki.nginx.org/HttpLuaModule

¤  Provides a synchronous yet non-blocking API to Nginx

¤  Very fast, if compiled with --luajit

Use cases of Nginx + Lua

¤  Smart Programmable Router

¤  Proxy

¤  Load Balancer

¤  A/B Testing

¤  Complex Caching

¤  Advanced logging

¤  API Aggregator

¤  Authentication Services

¤  And much more…

HttpLuaModule Directives ngx_lua Nginx Phase Context

init_by_lua loading-config http

init_worker_by_lua starting-worker http

set_by_lua rewrite server, server if, location, location if

rewrite_by_lua rewrite tail http, server, location, location if

access_by_lua access tail http, server, location, location if

content_by_lua content location, location if

header_filter_by_lua output-header-filter http, server, location, location if

body_filter_by_lua output-body-filter http, server, location, location if

log_by_lua log http, server, location, location if

Where lua module acts on? server Write

find config

rewrite

post rewrite

pre-access

access

post-access

try-files

content

logging

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content_by_lua

*_by_lua_file

1  location /hellolua { 2  content_by_lua ' 3  local name = ngx.var.arg_name or "Anonymous" 4  ngx.say("Hello, ", name, "!") 5  '; 6  }

1  location /hellolua { 2  content_by_lua_file 'path/to/file.lua’ 3  }

1  location /hello { 2  set_unescape_uri $name $arg_name; 3  set_if_empty $name "Anonymous"; 4  echo "Hello, $name!"; 5  }

Result

1  location /hellolua { 2  default_type 'text/plain’; 3  content_by_lua ' 4  local name = ngx.var.arg_name or "Anonymous" 5  ngx.say("Hello, ", name, "!") 6  '; 7  }

What will we see today?

¤  lua_shared_dict ¤  Declares a shared memory zone

¤  log_by_lua ¤  Acts on the log phase

¤  Sub-requests ¤  Calls subrequests URIs

¤  Cosockets ¤  Send and receive on TCP or Unix domain sockets

¤  Use Cases / Demo

Shared Data

1  http { 2  lua_shared_dict dogs 10m; 3  server { 4  location /set { 5  content_by_lua ' 6  local dogs = ngx.shared.dogs 7  dogs:set("Jim", 8) 8  ngx.say("STORED") 9  '; 10  } 11  location /get { 12  content_by_lua ' 13  local dogs = ngx.shared.dogs 14  ngx.say(dogs:get("Jim")) 15  '; 16  } 17  } 18  }

Counter: Shared Data

1  http { 2  lua_shared_dict count10m; 3  server { 4  location /counter { 5  content_by_lua ' 6  ngx.shared.count:incr("hits", 1) 7  ngx.say(ngx.shared.count:get("hits")) 8  '; 9  } 10  } 11  }

log_by_lua

1  location / { 2  proxy_pass http://mybackend;

3  log_by_lua ' 4  if tonumber(ngx.var.upstream_response_time) >= 5 then 5  ngx.log(ngx.WARN, "[SLOW] Ngx upstream response time: " .. ngx.var.upstream_response_time ..

"s from " .. ngx.var.upstream_addr); 6  end 7  '; 8  }

Log slow requests >5 seconds

1  location /{ 2  log_by_lua ’ 3  if ngx.status >= 500 then 4  send_email… 5  end'; 6  }

Tell me about 500 error

Sub-requests

¤  Issues a synchronous but still non-blocking Nginx Subrequest using uri.

¤  Subrequests just mimic the HTTP interface. ¤  There is no extra HTTP/TCP traffic involved.

¤  Everything works internally, efficiently, on the C level.

¤  Subrequests issued by ngx.location.capture inherit all the request headers of the current request

ngx.location.capture

¤  Subrequests ¤  Example: Deprecated Route

1  location /old_api { 2  content_by_lua ' 3  local res = ngx.location.capture(”/new_api") 4  if res.status >= 500 then 5  ngx.exit(res.status) 6  end 7  ngx.status = res.status 8  ngx.say("This is coming from another request") 9  ngx.say(res.body) 10  '; 11 }

ngx.location.capture_multi

¤  Multi Subrequests ¤  Example: Cheating on a chatty REST API

1  location /mobile/home { 2  content_by_lua ’ 3  res1, res2, res3 = ngx.location.capture_multi{ 4  { "/categories"}, 5  { "/popular"}, 6  { "/movies", 16}, 7  { "/movies", 19}, 8  } 9  ngx.say(cjson.encode(res1, res2, res3)) 10  '; 11 }

cosockets

¤  Send and receive on TCP or Unix domain sockets.

¤  API compatible with LuaSocket, yet non-blocking to Nginx.

¤  Has a keepalive mechanism to avoid connect/close for each request.

cosockets examples

1  local sock = ngx.socket.tcp() 2  local ok, err = sock:connect("127.0.0.1", 1234) 3  local bytes, err = sock:send("hello") 4  local data, err = sock:receive("*l")

1  local sock = ngx.socket.udp() 2  local ok, err = sock:setpeer("127.0.0.1", 5432) 3  local bytes, err = sock:send("my query") 4  local dgram, err = sock:receive()

Connect, bind, receive, send, close ….

cosocket based libraries

¤  lua-resty-memcached

¤  lua-resty-redis

¤  lua-resty-mysql

¤  Lua-resty-upload

Courtesy of OpenResty

Non Blocking I/O lua-resty-memcached

1  location /memcached { 2  content_by_lua ' 3  local memcached = require "resty.memcached" 4  local memc = memcached:new() 5  local ok, err = memc:connect("127.0.0.1", 11211)

6  local ok, err = memc:set("foo", "bar", 3600) 7  if ok then 8  ngx.say("STORED") 9  end

10  memc:set_keepalive() 11  '; 12 }

Cases

¤  Load Balancer

¤  Inject Javascript tags into HTML

¤  Authentication Module

Case: Dead Simple Load Balancer 1  upstream instance1 { 2  server privatehost1:3000; 3  }

4  upstream instance2 { 5  server privatehost2:3000; 6  }

7  server { 8  listen 80;

9  set $root /var/www; 10  set $backend http://instance1;

11  rewrite_by_lua ' 12  if (ngx.var.user_id % 2 == 0) then 13  ngx.var.backend = http://instance2 14  end 15  ';

16  proxy_pass $backend; 17  }

Case: Inject Google Analytics Code

1  location / { 2  proxy_pass http://mybackend; 3  body_filter_by_lua ‘ 4  local chunk, eof = ngx.arg[1], ngx.arg[2] 5  local google_code = "<script type="text/javascript”> 6  var _gaq = _gaq || [];_gaq.push(['_setAccount', 'UA-XXXXXXXX-1']); 7  .... Google script code …..

8  </script></body>"

9  string.gsub(chunk,"</body>",google_code)

10  '; 11  }

Case: CAS Auth Lua Module

Nginx Lua Auth Mod

Authorize

/panel

Apps

Demo App

Thank you!