介绍

本项目是基于openresty/lua-resty-redis 是章亦春（agentzh）开发的openresty中的操作redis的库。进行二次封装的工具库。核心功能还是由openresty/lua-resty-redis完成的。

本文假设你已经了解nginx+lua或者openresty如何使用lua脚本(e.g. lua_package_path配置,*_by_lua_file),基础的redis相关知识，以及openresty/lua-resty-redis的基本使用方法(openresty/lua-resty-redis#README.md)。

安装(Install)

# opm 安装
opm get anjia0532/lua-resty-redis-util

# luarocks 安装
luarocks install lua-resty-redis-util

对比

截取官方部分代码，进行说明

    local redis = require "resty.redis"
    local red = redis:new()

    red:set_timeout(1000) -- 1 sec --设置超时时间

    local ok, err = red:connect("127.0.0.1", 6379) --设置redis的host和port
    if not ok then --判断生成连接是否失败
        ngx.say("failed to connect: ", err)
        return
    end

    ok, err = red:set("dog", "an animal") --插入键值(类似 mysql insert)
    if not ok then --判断操作是否成功
        ngx.say("failed to set dog: ", err)
        return
    end

    ngx.say("set result: ", ok) -- 页面输出结果
    -- put it into the connection pool of size 100,
    -- with 10 seconds max idle time
    local ok, err = red:set_keepalive(10000, 100) --将连接放入连接池,100个连接，最长10秒的闲置时间
    if not ok then --判断放池结果
        ngx.say("failed to set keepalive: ", err)
        return
    end
    -- 如果不放池，用完就关闭的话，用下面的写法
    -- or just close the connection right away:
    -- local ok, err = red:close()
    -- if not ok then
    --     ngx.say("failed to close: ", err)
    --     return
    -- end

如果用过java，c#等面向对象的语言，就会觉得这么写太。。。。了，必须重构啊，暴露太多无关细节了，导致代码中有大量重复代码了。

同样的内容，使用我封装后的代码。隐藏了设置连接池，取连接，用完后放回连接池等操作。

    -- 依赖库
    local redis = require "resty.redis-util"
    -- 初始化
    local red = redis:new();
    -- 插入键值
    local ok,err = red:set("dog","an animal")
    -- 判断结果
    if not ok then
      ngx.say("failed to set dog:",err)
      return
    end
    -- 页面打印结果
    ngx.say("set result: ", ok) -- 页面输出结果

注意事项(Note)

默认值(Default Value)

local red = redis:new();
--使用了默认值,等同于
local red2 = redis:new({
                            host='127.0.0.1',
                            port=6379,
                            db_index=0,
                            password=nil,
                            timeout=1000,
                            keepalive=60000,
                            pool_size=100
                        });

• host: redis host,default: 127.0.0.1
• port: redis port,default:6379
• db_index: redis库索引(默认0-15 共16个库)，默认的就是0库(建议用不同端口开不同实例或者用不同前缀，因为换库需要用select命令),default:0
• password: redis auth 认证的密码
• timeout: redis连接超时时间,default: 1000 (1s)
• keepalive: redis连接池的最大闲置时间, default: 60000 (1m)
• pool_size: redis连接池大小, default: 100

subscribe

因为没有用到pub/sub，所以只是简单的实现了(un)subscribe，没有继续实现(un)psubscribe(模式订阅), 参考 Redis 接口的二次封装（发布订阅）

    local cjson = require "cjson"
    local red = redis:new();

    -- 订阅dog频道
    local func  = red:subscribe( "dog" )

    -- 判断是否成功订阅
    if not func then
      return nil
    end

    -- 获取值
    local res, err = func() --func()=func(true)
    -- 如果失败，取消订阅
    if err then
        func(false)
    end

    -- 如果取到结果，进行页面输出
    if res then
        ngx.say("1: receive: ", cjson.encode(res))
    end

    -- 再次获取
    res, err = func()

    -- 获取成功后，取消订阅 func(false)
    if res then
        ngx.say("2: receive: ", cjson.encode(res))
        func(false)
    end

pipeline

参考 openresty/lua-resty-redis#Synopsis

    local cjson = require "cjson"
    local red = redis:new();

    red:init_pipeline()

    red:set("cat", "Marry")
    red:set("horse", "Bob")
    red:get("cat")
    red:get("horse")

    local results, err = red:commit_pipeline()

    if not results then
        ngx.say("failed to commit the pipelined requests: ", err)
        return
    else
        ngx.say("pipeline",cjson.encode(results))
    end
    -- output pipeline["OK","OK","Marry","Bob"]

script

参考 script 压缩复杂请求

    local red = redis:new();

    local id = 1
    local res, err = red:eval([[
        -- 注意在 Redis 执行脚本的时候，从 KEYS/ARGV 取出来的值类型为 string
        local info = redis.call('get', KEYS[1])
        info = cjson.decode(info)
        local g_id = info.gid

        local g_info = redis.call('get', g_id)
        return g_info
        ]], 1, id)

    if not res then
       ngx.say("failed to get the group info: ", err)
       return
    end

    ngx.say("script",res)

鸣谢(Thanks)

本工具借鉴了 lua-resty-redis/lib/resty/redis.lua 和 Redis 接口的二次封装 的代码

反馈(Feedback)

如果有问题，欢迎提 issues

Copyright and License

This module is licensed under the BSD license.

Copyright (C) 2017-, by AnJia anjia0532@gmail.com.

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.