openresty--4--缓存

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shared_dict 字典缓存

  1. 修改nginx.conf ，申请缓存lua_shared_dict，128M。 

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    lua_shared_dict my_cahe 128m;

  2. 在lua文件中使用缓存“my_cahe”。

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    function get_from_cache(key)
    	local mycache = ngx.shared.my_cache
    	local value = mycache:get(key)
    	return value
    end

shared_dict多个work共享；会有锁的操作，保证数据的原子性；会根据功能拆分出多个shared_dict避免锁的竞争； lua_shared_dict

lua_resty_lrucache

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-- file myapp.lua: example "myapp" module

local _M = {}

-- alternatively: local lrucache = require "resty.lrucache.pureffi"
local lrucache = require "resty.lrucache"

-- we need to initialize the cache on the lua module level so that
-- it can be shared by all the requests served by each nginx worker process:
local c, err = lrucache.new(200)  -- allow up to 200 items in the cache
if not c then
    return error("failed to create the cache: " .. (err or "unknown"))
end

function _M.go()
    c:set("dog", 32)
    c:set("cat", 56)
    ngx.say("dog: ", c:get("dog"))
    ngx.say("cat: ", c:get("cat"))

    c:set("dog", { age = 10 }, 0.1)  -- expire in 0.1 sec
    c:delete("dog")

    c:flush_all()  -- flush all the cached data
end

return _M

每个work单独占用，不会共享。 lua_restyy_lurcache