Nginx-lua
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This document discusses using NGINX with embedded Lua scripting via OpenResty. Lua is a lightweight scripting language used in many applications and games. OpenResty bundles NGINX with LuaJIT and modules to allow full control over every stage of request processing with non-blocking Lua scripts. Examples show how to build a REST API for user scores with Redis using Lua scripts to handle data retrieval, modification and aggregation directly from NGINX.
![LuaJIT
• JIT compilation for lua code
• High performance (3-100x)
• Low memory footprint
• Crossplatform
• Cross-architecture (x86, ARM, MIPS,
PPC
• local ffi = require("ffi")
ffi.cdef[[
int printf(const char *fmt, ...);
]]
ffi.C.printf("Hello %s!", "world")](https://image.slidesharecdn.com/openresty-150603130047-lva1-app6892/85/Nginx-lua-4-320.jpg)
![GET /scores
local keys, err = red:keys("*")
local scores = {}
for i, key in ipairs(keys) do
scores[key] = red:get(key)
end
ngx.header.content_type = "text/plain"
ngx.say(json.encode(scores))](https://image.slidesharecdn.com/openresty-150603130047-lva1-app6892/85/Nginx-lua-12-320.jpg)
![GET /scores/max/<id1>,...,<idN>
local max = 0
for key in string.gmatch(ngx.var.key, '([^,]+)') do
local res = ngx.location.capture("/scores/" .. key)
data = json.decode(res.body)
if tonumber(data.value) > max then
max = tonumber(data.value)
end
end
ngx.say(json.encode({ max = max }))](https://image.slidesharecdn.com/openresty-150603130047-lva1-app6892/85/Nginx-lua-18-320.jpg)
Nginx-lua
- 1. NGINX + Lua Using NGINX/OpenResty with embedded Lua Epifanov Ivan, Lead Developer
- 2. Lua • Fast • Light (241K) • Simple • Powerfull • Embeddable • Portable Lua do Pesadelo (Nightmare Moon)
- 3. Who uses Lua? • Games: WoW, Angry Birds, Baldur's Gate, Civilization V, Crysis, HoMM V, L.A. Noire, etc. • Software: Lightroom, MySQL proxy, MySQL Workbench, Celestia, Far Manager, GIMP, MediaWiki, etc. • Misc.: Mercedes Autos, LG Smart TV, Space Shuttle Gas Detection, etc.
- 4. LuaJIT • JIT compilation for lua code • High performance (3-100x) • Low memory footprint • Crossplatform • Cross-architecture (x86, ARM, MIPS, PPC • local ffi = require("ffi") ffi.cdef[[ int printf(const char *fmt, ...); ]] ffi.C.printf("Hello %s!", "world")
- 5. OpenResty/NGINX-LUA • NGINX bundle with luajit and additional modules. • Developed by TaoBao and CloudFlare • Access to every processing stage of nginx • Non-blocking without callback-hell • co-sockets, shared pool and sub- requests
- 6. Full control • init_by_lua(file) • init_worker_by_lua(file) • set_by_lua(file) • log_by_lua(file) • content_by_lua(file) • header_filter_by_lua(file) • access_by_lua(file) • rewrite_by_lua(file)
- 7. What • Databases: lua-resty-redis, lua-resty- mysql, etc. • Templates: lua-resty-template, etlua • Frameworks: Lapis • Preprocessors: Moonscript (coffiescript-like syntax)
- 8. Where • Image Server, for image resizes (now) • Image Server, for queue, API, control (in the future) • Mobile detection • EDGE-side block cache • Maybe parts of SSO API, like cookie- setter
- 9. For example... Redis RESTfull api for userscores • GET /scores return userid list • GET/PUT/POST/DELETE /scores/<id> manipulate user scores
- 10. Init http { ... init_by_lua ' json = require "cjson"; redis = require "resty.redis" '; ... server { ... set $redis_host "192.168.2.104"; set $redis_port "6379"; set $redis_pass "nightmaremoon"; ... } ... }
- 11. Init local red = redis:new() local ok, err = red:connect(ngx.var.redis_host, ngx.var.redis_port) if not ok then ngx.say("failed to connect: ", err) return end local ok, err = red:auth(ngx.var.redis_pass) if not ok then ngx.say("failed to auth: ", err) return end
- 12. GET /scores local keys, err = red:keys("*") local scores = {} for i, key in ipairs(keys) do scores[key] = red:get(key) end ngx.header.content_type = "text/plain" ngx.say(json.encode(scores))
- 13. GET /score/<userid> location ~* ^/keys/(?<key>.*)$ { content_by_lua ' -- ... (connect and auth) local val, err = red:get("user:score:" .. ngx.var.key) ngx.say(json.encode({ value = val })) '; }
- 14. DELETE /scores/<userid> local method = ngx.req.get_method() if method == "GET" then ... elseif method == "PUT" then ... elseif method == "DELETE" then red:delete("user:score:" .. ngx.var.key) ngx.say(json.encode({result = "success"})) end
- 15. PUT /scores/<userid> data = json.decode(ngx.req.get_body_data()) red:set("user:score:" .. ngx.var.key, data.value) ngx.req.set_method(ngx.HTTP_GET) ngx.exec("/scores/" .. ngx.var.key)
- 16. GET /scores/max local max = 0 local keys = redis.call('keys', 'user:score:*'); for i, key in ipairs(keys) do local value = tonumber(redis.call('get', key)); if value > max then max = value end end return max
- 17. GET /scores/max local sha, err = red:script("load","...") local val, err = red:evalsha(sha, 0) ngx.say(json.encode({ max = val }))
- 18. GET /scores/max/<id1>,...,<idN> local max = 0 for key in string.gmatch(ngx.var.key, '([^,]+)') do local res = ngx.location.capture("/scores/" .. key) data = json.decode(res.body) if tonumber(data.value) > max then max = tonumber(data.value) end end ngx.say(json.encode({ max = max }))
- 19. What to read • https://gist.github.com/isage/509d99cf4 def36014f5c • http://wiki.nginx.org/HttpLuaModule • http://openresty.org • search github for lua-resty*