Nginx - Run command on HTTP request - nginx

Question

How can I run a command like shutdown when my Nginx receives an HTTP request?
I read about writing modules for this, but I find it overkilling, I just need to shutdown the computer when an HTTP request is answered.

Answer 1

There is an impressively creative solution to implement some kind of shell webhooks I found recently on GitHub (all credits goes to the author).
It consist of three parts.
A systemd unit to run a socat utility listening the loopback network interface (don't open used TCP port to the outer world in any case!):
[Unit]
Description=socat-based cmd api
After=network.target
[Service]
User=nobody
Group=nobody
ExecStart=/usr/bin/socat UDP-LISTEN:50333,fork,bind=127.0.0.1 EXEC:/opt/bin/shell-webhook
Restart=always
[Install]
WantedBy=multi-user.target
A shell script to be placed somewhere (the above unit assumes it to be the /opt/bin/shell-webhook):
#!/bin/bash
LOG=/var/log/shell-webhook.log
declare -a DATA
read -a DATA
cmd=${DATA[4]}
case ${cmd} in
reboot)
echo "Executing reboot" >> ${LOG}
shutdown -r now
;;
shutdown)
echo "Executing shutdown" >> ${LOG}
shutdown -P now
;;
*)
echo "Unknown command $cmd" >> ${LOG}
;;
esac
An nginx-relevant configuration part (consider preventing access to this location using some kind of access control - allow/deny rules, basic auth, etc.):
log_format shellwebhook '$cmd\n';
server {
...
location ~* ^/cmd/(\w+)$ {
set $cmd $1;
return 200 "$cmd";
access_log syslog:server=127.0.0.1:50333,facility=local7,tag=nginx,severity=info,nohostname shellwebhook;
}
}