[luatex] MySQL driver not found from inside LuaLaTeX

[Faheem Mitha]

Hi Sergei,

This comes up a lot, and the solution really should be easier to find.

On Wed, 28 Feb 2024, sergei.naumov at gmail.com wrote:

> Hi!

> I am new to LuaTeX and LuaLaTeX, please, bear with my ignorance of some 
> probably basic things. :-) I need to get strings from MySQL database and 
> the test Lua code that does it works fine when it is called from the 
> command line:

You're probably looking for https://ctan.org/pkg/luapackageloader?lang=en

Regards, Faheem Mitha

> require("string")
> function projects_from_db ()
>     DBI = require("DBI")
>     dbh = assert(DBI.Connect('MySQL','serge', 'serge', 'serge', 'localhost', 3306))
>     sth = assert(dbh:prepare('SELECT name,budget FROM projects'))
>     sth:execute()
>     for row in sth:rows() do
>         print(string.format("%-55s & %7.1f \\\\",row[1],row[2]))
>     end
>     dbh:close()
> end
> 
> -- projects_from_db()
> 
> However, when I put it into latex file
> 
> \usepackage{luacode}
> \usepackage{luapackageloader}
> \directlua{dofile('dbd.lua')}
> \newcommand{\projectsfromdb}{\luadirect{projects_from_db()}}
> 
> It says that MySQL driver can not be found:
> ./DBI.lua:53: Cannot load driver MySQL. Available drivers are: (None)
> stack traceback:
>        [C]: in function 'error'
>        ./DBI.lua:53: in function 'DBI.Connect'
>        dbd.lua:6: in function 'projects_from_db'
>        [\directlua]:1: in main chunk.
> \luadirect ... { \luacode at maybe@printdbg {#1} #1 }
>                                                  
> l.64    \projectsfromdb
> Why is that? I checked package.cpath from Lua and the necessary path is there:
> 
> Lua 5.3.6  Copyright (C) 1994-2020 Lua.org, PUC-Rio
> > package.cpath
> /usr/lib64/lua/5.3/?.so;/usr/lib64/lua/5.3/loadall.so;./?.so
> 
> I tried to set a few environment variables:
> 
> LUAROCKS_CPATH=/usr/lib64/lua/5.3
> LUAROCKS_PATH=/usr/share/lua/5.3
> 
> but it did not make any difference
> 
> --
> Thanks,
> Sergei
> 
>