Redis connection error

asp.2073 · 2019-07-20T16:09:29+00:00

Hi folks, I recently wrote a blog post on LuaJIT's GC64 mode, especially in the context of OpenResty: https://blog.openresty.com/en/luajit-gc64-mode/...

Redis connection error

asp.2073

I have a file called redis_opr.lua and all Redis operation will be in there. this is the code:

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


red:set_timeout(1000) -- 1 sec




--  Set in Redis
function set_redis( key, data )
 local redis_ok, redis_err = red:connect("127.0.0.1", 6379)
 if not redis_ok then
 return false
 end


 done, err = red:set(key, tostring(data))
    if (err) or (not done) then
        return false
    end


    return done
end


-- Get from Redis
function get_redis( key )
 local redis_ok, redis_err = red:connect("127.0.0.1", 6379)
 if not redis_ok then
 return false
 end


 local res, err = red:get( key )
    if (err) or (not res) or (tostring(res) == 'userdata: NULL') then 
        return false
    end   


    return res
end

There are 2 functions as you can see. Get and Set for making it easy to query to Redis.

The problem is, it works only on some requests. On every 2 requests, It returns one a connection error.

What is the problem?

zchao1995

Hello!

So your module uses lua-resty-redis, which in turn uses ngx_lua's builtin API cosocket.

What you should be cautious is the scope of cosocket object is limited to a request, since

it uses the request's memory pool. You'd better to instantiate the redis instance once you call

get_redis or set_redis.