help request: file descriptor overflow when use request-id plugin nanoid algorithm

[saiyan-qx]

Description

When i use request-id plugin nanoid algorithm，file descriptor increse to the limit of worker_rlimit_nofile : 20480，then cause the error : Too many open files。

I use lsof -p command, find a lot of file descriptors like this:
openresty 955 nfsnobody 45r CHR 1,9 0t0 71005690 /dev/urandom
openresty 955 nfsnobody 46r CHR 1,9 0t0 71005690 /dev/urandom
openresty 955 nfsnobody 47r CHR 1,9 0t0 71005690 /dev/urandom
openresty 955 nfsnobody 48r CHR 1,9 0t0 71005690 /dev/urandom
openresty 955 nfsnobody 49r CHR 1,9 0t0 71005690 /dev/urandom
openresty 955 nfsnobody 50r CHR 1,9 0t0 71005690 /dev/urandom

Thanks!

Environment

• APISIX version 3.0
• Operating system : Linux XXX 3.10.0-1160.80.1.el7.x86_64 change: added doc of how to load plugin. #1 SMP Tue Nov 8 15:48:59 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
• OpenResty / Nginx version :nginx version: openresty/1.21.4.1

[tokers]

APISIX uses lua nanoid. It might be caused by the nanoid lib.

[saiyan-qx]

Eureka!The code of lua-resty-nanoid lib does not execute the close method. @tokers

[tokers]

You may try to submit a PR for the lua-resty-nanoid repo, then let's upgrade the dependency in APISIX.

[liweitianux]

Interesting, but I found the upstream lua-resty-nanoid project doesn't provide the "Issues" section...

What's more, the lua-resty-nanoid project simply imported the C code from nerdypepper/nanoid, and there have been an issue about the missing fclose().

[liweitianux]

And I believe lua-resty-nanoid also has a memory leak issue. The ID buffer was allocated by malloc() but was never freed. It should be freed by the caller, i.e., the Lua C interface.

[liweitianux]

On the other hand, I almost finished implementing a new Nano ID module for Lua (and C). I'll need to polish a bit more and try to get it onto LuaRocks. And I'll report back then.

See: https://github.com/liweitianux/nanoid

[shreemaan-abhishek]

@liweitianux, any updates?

[liweitianux]

Sorry. I've finished the nanoid code, but I haven't tried to publish it to LuaRocks yet. Will try it this weekend.

[shreemaan-abhishek]

@liweitianux, looking forward to it.

[liweitianux]

Hi @shreemaan-abhishek , so I've polished the nanoid code and submitted it to LuaRocks at https://luarocks.org/modules/liweitianux/lua-nanoid .

I've documented the module usage in the README at https://github.com/liweitianux/nanoid .

Please give it a try. Sorry for the delay.

I'd like it to be used in APISIX, which requires another MR. Let's see.

Cheers.

[liweitianux]

And I believe lua-resty-nanoid also has a memory leak issue. The ID buffer was allocated by malloc() but was never freed. It should be freed by the caller, i.e., the Lua C interface.

Furthermore, that code doesn't NUL-terminate the C string, so I sometimes saw garbled code in the generated IDs... It's quite messy.

[shreemaan-abhishek]

@liweitianux I get the following error when installing the luarock:

lua-nanoid 1.0.0-1 depends on lua >= 5.1 (5.1-1 provided by VM)
env MACOSX_DEPLOYMENT_TARGET=11.0 gcc -O2 -fPIC -I/opt/homebrew/opt/lua@5.1/include/lua5.1 -c nanoid_lua.c -o nanoid_lua.o -DNDEBUG
env MACOSX_DEPLOYMENT_TARGET=11.0 gcc -O2 -fPIC -I/opt/homebrew/opt/lua@5.1/include/lua5.1 -c nanoid.c -o nanoid.o -DNDEBUG
nanoid.c:90:9: error: call to undeclared function 'getrandom'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        getrandom(bytes, sizeof(bytes), 0);
        ^
1 error generated.

Error: Failed installing dependency: https://luarocks.org/lua-nanoid-1.0.0-1.rockspec - Build error: Failed compiling object nanoid.o
make: *** [deps] Error 1

[liweitianux]

Hi @shreemaan-abhishek , please report the issues regarding my lua-nanoid to its own project at https://github.com/liweitianux/nanoid .

The above issue is because getrandom() isn't available on macOS. Better to use arc4random(3) instead, but I need to add some compatibility code to support some old Linux versions, like CentOS 7 ...

[shreemaan-abhishek]

Done!

[shreemaan-abhishek]

@liweitianux, any updates?

[Vacant2333]

@liweitianux @shreemaan-abhishek if its done, we can close the issue now

[liweitianux]

My nanoid module should work, although there is more optimization to improve the performance on old systems (e.g., CentOS 7).

[aikin-vip]

sorry, I haven't paid attention to this place for a long time. I have read your previous discussion, and what I need to do now seems to be in two ways:

1. use the @liweitianux code repo lua-nanoid and publish it to luarocks as nanoid-1.0.0-1. then modify this part of the main branch code of apisix.

   dependency change at :

   apisix/apisix-master-0.rockspec

   Line 79 in 231412d

   "nanoid = 0.1-1",

   it will be "nanoid = 1.0.0-1",

   generate method change at:

   apisix/apisix/plugins/request-id.lua

   Line 83 in 231412d

   return nanoid.safe_simple()

   it will be return nanoid.generate()

2. The second way is to use the published module, lua-nanoid, and then modify the lua dependency of apisix.

   dependency version change at :

   apisix/apisix-master-0.rockspec

   Line 79 in 231412d

   "nanoid = 0.1-1",

   it will be "lua-nanoid = 1.1.1-1",

   generate method change at:

   apisix/apisix/plugins/request-id.lua

   Line 83 in 231412d

   return nanoid.safe_simple()

   it will be return nanoid.generate()

   apisix/apisix/plugins/request-id.lua

   Line 21 in 231412d

   local nanoid = require("nanoid")

   it will be local nanoid = require("lua-nanoid")

   which one do you suggest is better? @shreemaan-abhishek

   In addition, thanks @liweitianux 's contribution.

[liweitianux]

Hi @aikin-vip,

apisix/apisix/plugins/request-id.lua

Line 21 in 231412d

local nanoid = require("nanoid")

it will be local nanoid = require("lua-nanoid")

This should be local nanoid = require("nanoid"), as documented in my README.

Cheers.

[aikin-vip]

Hi @liweitianux
I have submitted the repair code and added dynamic parameters, waiting for merging 🎉🎉🎉