Sorry, I sent the bug report incomplete.
The problem is that the lua-redis package does not close the file
descriptors when calling redis quit or shutdown. Here in this report to the
upstream is the problem explained https://github.com/nrk/redis-lua/issues/71
I detected the problem when running the software kamailio-proxy. After
running some time I got this error
ERROR: app_lua [app_lua_api.c:719]: app_lua_run_ex(): error from Lua:
/usr/share/lua/5.1/redis.lua:813: could not connect to 127.0.0.1:6379 [Too
many open files]
When running a lsof there where a lot of this entries:
kamailio 2205 kamailio 4u sock 0,8
0t0 33760 protocol: TCP
kamailio 2205 kamailio 13u sock 0,8
0t0 33758 protocol: TCP
kamailio 2205 kamailio 17u sock 0,8
0t0 130221 protocol: TCP
kamailio 2205 kamailio 18u sock 0,8
0t0 130222 protocol: TCP
kamailio 2205 kamailio 19u sock 0,8
0t0 143025 protocol: TCP
To reproduce the problem I wrote a lua script, to use first
ulimit -m 1024
lua pe.lua
...
uccessfully connected and pinged Redis. Total connections: 1018
Successfully connected and pinged Redis. Total connections: 1019
Successfully connected and pinged Redis. Total connections: 1020
Successfully connected and pinged Redis. Total connections: 1021
Error connecting to Redis: /usr/share/lua/5.3/redis.lua:810: could not
connect to 127.0.0.1:6379 [Too many open files]
Reached the maximum open files limit. Sleeping for 10 hours...
The script is:
local redis = require "redis" -- Ensure this library is installed
(lua-redis)
local socket = require "socket" -- For sleeping
local redis_host = "127.0.0.1"
local redis_port = 6379
local connection_counter = 0 -- Initialize connection counter
local client_list = {} -- Initialize an array to store all client
connections
-- Main loop
local attempt = 0
while true do
-- Protected call to catch the error and handle it
local success, client_or_error = pcall(function()
local client, err = redis.connect(redis_host, redis_port)
if err then
return nil, err
end
-- Save the client to the client_list array
table.insert(client_list, client)
connection_counter = connection_counter + 1 -- Increment the
connection counter
local res, err = client:ping()
if err then
return nil, err
end
client:quit() -- This will not properly release the TCP socket,
causing lingering connections
return client
end)
if not success then
-- If the pcall failed (error occurred)
print("Error connecting to Redis: " .. client_or_error)
-- Check if the error is "Too many open files"
if string.match(client_or_error, "Too many open files") then
print("Reached the maximum open files limit. Sleeping for 10
hours...")
socket.sleep(10 * 60 * 60) -- Sleep for 10 hours
else
-- If it's another error, break out of the loop
break
end
else
-- If success, print the connection count
print("Successfully connected and pinged Redis. Total connections:
" .. connection_counter)
end
end
-- Print out the number of connections made
print("Connections made: " .. connection_counter)
-- Do your lsof here to check the connections
print("Do your lsof")
-- Sleep for 10 hours to allow you to inspect the system
socket.sleep(10 * 60 * 60) -- Sleep for 10 hours
Instead
When editing /usr/share/lua/5.3/redis.lua and adding
client_prototype.quit = function(client)
request.multibulk(client, 'QUIT')
client.network.socket:shutdown()
client.network.socket:close() -- ADDED
return true
end
client_prototype.shutdown = function(client)
request.multibulk(client, 'SHUTDOWN')
client.network.socket:shutdown()
client.network.socket:close() -- ADDED
end
With this change the file descriptors are properly closed.
Cheers
Alejandro
