Easy notification of arbitrary events on remote Linux/Unix computer

Question

I am looking for a way to easily define one-time notifications of some events that take place on a Linux box. Events might include things like: file /tmp/my.lock is unlinked or process 666 finished or, maybe, something more complicated, like process 'backup.sh' closed file 'backup.tgz' AND process 'backup.sh' exited with return code 0.

Notifications should be also flexible. Like, notify 192.168.0.100 via org.freedesktop.Notifications.Notify or notify me@gmail.com via email.

Actually, it's something like Nagios, but designed for non-repeating events, with minimal, almost zero cost of task creation. Am I a dreamer? Should I write it myself? Or should I simply use shell scripting?

Answer 1

Nagios can exactly notify the events just one time.
We use it to open tickets.
Just set notification_interval = 0 (for both service and host) and you'll get the email/sms just once.

Answer 2

Just to add some more input to the should I write it myself question, you could create either a FIFO or flat file to use as a custom log, and add commands to your custom scripts that write important output to that log file. Or alternatively, you could create a simple script that periodically checks the status of important files and processes, and sends its output to that log.

To create the FIFO on the server:

mkfifo /var/log/mylog

To read the logs from the server:

ssh user@host "tail -f /var/log/mylog"

Source these functions into your custom scripts to easily write to the log:

function warning { echo -e "\e[33;1m :: \e[0m$@" > /var/log/mylog; };
function error { echo -e "\e[31;1m :: \e[0m$@" > /var/log/mylog; };
function information { echo -e "\e[32;1m :: \e[0m$@" > /var/log/mylog; };

And then write entries to the log by issuing these commands:

information "Some text"
warning "Some more text"
error "Some important text"

You can similarly add a shell function that uses sendmail (or similar) to mail you.

Answer 3

I would think a combination of inotifywatch, ps, logger and syslog in some custom scripts might do the trick.