Lua tech talk

Lua tech talk

1. 1. Modulos Nginx usando Lua Rachad Honein
2. 2. NGINX ¤ HTTP server with High Performance ¤ Events based architecture ¤ Small footprint on memory and processing ¤ Declarative Configuration ¤ Like Apache natively extensible through C modules
3. 3. Market Share
4. 4. Nginx Configuration Directives 1 location /hello { 2 set_unescape_uri $name $arg_name; 3 set_if_empty $name "Anonymous"; 4 echo "Hello, $name!"; 5 }
5. 5. Lua
6. 6. Lua
7. 7. 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
8. 8. 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
9. 9. Lua ¤ Fast language: Comparison with other scripting languages
10. 10. 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
11. 11. 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…
12. 12. 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
13. 13. Where lua module acts on? server Write find config rewrite post rewrite pre-access access post-access try-files content logging request Request Lifetime inside NGINX
14. 14. content_by_lua 1 location /hello { 2 set_unescape_uri $name $arg_name; 3 set_if_empty $name "Anonymous"; 4 echo "Hello, $name!"; 5 } 1 location /hellolua { 2 content_by_lua ' 3 local name = ngx.var.arg_name or "Anonymous" 4 ngx.say("Hello, ", name, "!") 5 '; 6 } *_by_lua_file 1 location /hellolua { 2 content_by_lua_file 'path/to/file.lua’ 3 }
15. 15. 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 }
16. 16. 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
17. 17. 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 }
18. 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 }
19. 19. log_by_lua Log slow requests >5 seconds 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 } Tell me about 500 error 1 location /{ 2 log_by_lua ’ 3 if ngx.status >= 500 then 4 send_email… 5 end'; 6 }
20. 20. 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
21. 21. 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 }
22. 22. 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 }
23. 23. 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.
24. 24. cosockets examples Connect, bind, receive, send, close …. 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()
25. 25. cosocket based libraries ¤ lua-resty-memcached ¤ lua-resty-redis ¤ lua-resty-mysql ¤ Lua-resty-upload Courtesy of OpenResty
26. 26. 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 }
27. 27. Cases ¤ Load Balancer ¤ Inject Javascript tags into HTML ¤ Authentication Module
28. 28. 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 }
29. 29. 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 }
30. 30. Case: CAS Auth Lua Module Nginx Lua Auth Mod Authorize /panel Apps
31. 31. Demo App
32. 32. Thank you!