lua-resty-redis 是一个基于 ngx_lua 的 Redis 客户端库，该 Lua 库利用了 ngx_lua 的 cosocket API，确保了 100% 的非阻塞行为。

连接

连接支持多种方式：

• unix domain socket
• ip + port
• 域名

server {
        location /test {
            # need to specify the resolver to resolve the hostname
            resolver 8.8.8.8;

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

                red:set_timeouts(1000, 1000, 1000) -- 1 sec

                -- connect to a unix domain socket file listened
                --     local ok, err = red:connect("unix:/path/to/redis.sock")

                -- connect via ip address directly
                local ok, err = red:connect("127.0.0.1", 6379)

                -- connect via hostname, need to specify resolver just like above
                local ok, err = red:connect("redis.openresty.com", 6379)

                if not ok then
                    ngx.say("failed to connect: ", err)
                    return
                end
                -- 认证
                local res, err = red:auth("foobared")
                if not res then
                    ngx.say("failed to authenticate: ", err)
                    return
                end
            }
        }
    }

操作

支持常见的redis命令

ngx.null 对应redis返回的nil，表示key不存在

 server {
        location /test {       
            content_by_lua_block {    
               -- 连接
           
               ok, err = red:set("dog", "an animal")
                if not ok then
                    ngx.say("failed to set dog: ", err)
                    return
                end

                ngx.say("set result: ", ok)

                local res, err = red:get("dog")
                if not res then
                    ngx.say("failed to get dog: ", err)
                    return
                end

                if res == ngx.null then
                    ngx.say("dog not found.")
                    return
                end

                ngx.say("dog: ", res)
        }
    }
}

pipeline

pipeline操作如下：

server {
        location /test {
            # need to specify the resolver to resolve the hostname
            resolver 8.8.8.8;

            content_by_lua_block {
                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
                end

                for i, res in ipairs(results) do
                    if type(res) == "table" then
                        if res[1] == false then
                            ngx.say("failed to run command ", i, ": ", res[2])
                        else
                            -- process the table value
                        end
                    else
                        -- process the scalar value
                    end
                end
            }
        }
    }

连接池

set_keepalive 支持将连接放入连接池中

      server {
        location /test {
            # need to specify the resolver to resolve the hostname
            resolver 8.8.8.8;

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

                red:set_timeouts(1000, 1000, 1000) -- 1 sec

                -- or connect to a unix domain socket file listened
                -- by a redis server:
                --     local ok, err = red:connect("unix:/path/to/redis.sock")

                -- connect via ip address directly
                local ok, err = red:connect("127.0.0.1", 6379)

                -- or connect via hostname, need to specify resolver just like above
                local ok, err = red:connect("redis.openresty.com", 6379)

                if not ok then
                    ngx.say("failed to connect: ", err)
                    return
                end

                ok, err = red:set("dog", "an animal")
                if not ok then
                    ngx.say("failed to set dog: ", err)
                    return
                end

                ngx.say("set result: ", ok)

                local res, err = red:get("dog")
                if not res then
                    ngx.say("failed to get dog: ", err)
                    return
                end

                if res == ngx.null then
                    ngx.say("dog not found.")
                    return
                end

                ngx.say("dog: ", res)

                
                -- 连接池
                -- put it into the connection pool of size 100,
                -- with 10 seconds max idle time
                local ok, err = red:set_keepalive(10000, 100)
                if not ok then
                    ngx.say("failed to set keepalive: ", err)
                    return
                end
            }
        }
    }