* * * * *
                                        
 Murphy's Law as applied to bugs: it is easier to find bugs in production than
                                 in development
                                        
Well, that [1] could have gone better.

One bug due to inattention and a difference between development and
production, and one “how the XXXX did this ever work in the first place?” bug
later, things should be working fine.

I am not going to say “I hope” this time.

The first bug prevented a proper HTTP (HyperText Transport Protocol) status
code from being generated, so Apache nicely generated a “500 Interner Server
Error” for me. Once I identified what was going on, it was a simple one line
fix [2], and an additional call to assert() [3] to help isolate such errors
in the future.

Now on to the other error … 

I added the concept of a hook [4] to mod_blog [5] a few years ago, and the
scripts I have for the various hooks all start with #!/usr/bin/env lua. Only
now they weren't running, and the error that was being logged wasn't exactly
helpful: entry-pre-hook='./validate.lua' status=127. There is no place in
mod_blog nor in the validate.lua script that exits with a status code of 127.
But the env program does! 

Nice to learn that.

But back to the issue at hand—I've been using these scripts for a few years
now, and only now is it failing? I eventually found out that the path Apache
is using is rather limited, and it no longer includes the Lua interpreter
(which on my server lives in /usr/local/bin). I had to change both scripts to
start with #!/usr/local/bin/lua and that fixed the issue to get the previous
post up.

Now that I think about it, I think I know why it finally stopped working
after a few years—I actually have an instance of Apache running that I didn't
start by hand, and the default path at boot time doesn't include
/usr/local/bin.

[1] gopher://gopher.conman.org/0Phlog:2024/08/23.1
[2] https://github.com/spc476/mod_blog/blob/77e9cab41d871623865979869d2d24321785ee6d/src/main_cgi.c#L587
[3] https://github.com/spc476/mod_blog/blob/77e9cab41d871623865979869d2d24321785ee6d/src/main_cgi.c#L95
[4] gopher://gopher.conman.org/0Phlog:2021/07/05.1
[5] https://github.com/spc476/mod_blog

Email author at sean@conman.org

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