RedisConnectionException: No connection is available to service this operation: EVAL

Question

I'm trying to implement Redis in an ASP.NET WebForms application (4.7.2). I downloaded the SessionProvider source code from https://github.com/Azure/aspnet-redis-providers. I'm using StackExchange.Redis 2.0+ .

After the login has been executed, this error is thrown:

Apparently, an attempt to eval some Lua script was made, and it failed (that was the conclusion for the closure of the StackExchange.Redis related issue).

So, assuming that assumption is correct, I extracted the offending script, and ran it with redis-cli --eval along with the keys and arguments.

local retArray = {} 
local lockValue = ARGV[1] 
local locked = redis.call('SETNX',KEYS[1],ARGV[1])        
local IsLocked = true

if locked == 0 then
    lockValue = redis.call('GET',KEYS[1])
else
    redis.call('EXPIRE',KEYS[1],ARGV[2])
    IsLocked = false
end

retArray[1] = lockValue
if lockValue == ARGV[1] then retArray[2] = redis.call('HGETALL',KEYS[2]) else retArray[2] = '' end

local SessionTimeout = redis.call('HGET', KEYS[3], 'SessionTimeout')
if SessionTimeout ~= false then 
    retArray[3] = SessionTimeout 
    redis.call('EXPIRE',KEYS[2], SessionTimeout) 
    redis.call('EXPIRE',KEYS[3], SessionTimeout) 
else 
    retArray[3] = '-1' 
end

retArray[4] = IsLocked
return retArray

It was successful.

Are there other issues that might throw this exception?

EDIT: Upgraded to 2.0. Still suffering from the same issues.

Answer 1

I tried to research for your issue, and then I found there is an issue No connection is available to service this operation using v.1.2.6 #762 of GitHub StackExchange/StackExchange.Redis repo which seems to be same with yours.

According to the note of a comment at the bottom of the GitHub issue, the other issue The "network stability" / 2.0 / "pipelines" rollup issue #871, there are some bugs need to be fixed for the version under 2.0, which likes network connection stability issue.

So I suggested that you can upgrade your current StackExchange.Redis (V1.2.6) to a latest stable 2.x version and try your code again. Meanwhile, please notice the Release Notes of Azure/aspnet-redis-providers to make the right and compatible versions to support your current code.