nginx lua: os.execute waitpid() failed (10: No child processes)

Question

So, I'm trying to execute a script on every request. I know how that sounds, this is for development environment.

I've added this to my nginx config access_by_lua_file "/opt/nginx/git-magic.lua";

git-magic.lua contains local status = os.execute('/opt/nginx/git-magic.sh')

And git-magic.sh contains: echo hello >> /tmp/git-magic

The issue is:

Whenever I hit any URL, I get the following in the nginx error log: 2012/09/27 15:35:48 [alert] 3241#0: waitpid() failed (10: No child processes)

Any ideas what I might be doing wrong?

wow... I'm having the EXACT same problem, and thought I was going nuts... I'm looking hard to see if I can find an answer... — user138906
– user138906, Commented Sep 28, 2012 at 18:31
Have you checked the obvious? Can nginx user access lua file? can nginx user write to /tmp/ ? — c2h5oh
– c2h5oh, Commented Oct 3, 2012 at 22:13
Lua can access git-magic.sh, git-magic.sh writes the right thing to /tmp/git-magic — Andrei Serdeliuc
– Andrei Serdeliuc, Commented Oct 3, 2012 at 22:19
See if there's an apparmor.d file for nginx. I had a problem convincing dhcpd to run a file when an address is requested, because apparmor was blocking it. — Tom O'Connor
– Tom O'Connor, Commented Oct 22, 2012 at 11:54

Frederik · Accepted Answer · 2014-06-30 10:07:10Z

The lua-resty-shell claims to solve this issue by supplying a non-blocking os.execute equivalent.

1 Answer 1