kiwix-serve should handle signals within docker

[rgaudin]

AFAIK, kiwix-serve has no signal management, leaving the microhttpd server started by libkiwix handling them.

When running on my computer, kiwix-serve properly exits on INT (^C), QUIT and TERM.

When running inside docker, none of those seem to have any impact. I always have to use KILL (which is handled by the system).

FYI, in docker, when using docker stop, it emmits a SIGTERM and waits for 10s until it uses SIGKILL. It is possible to send any signal using docker kill -s {signal}.

This behavior is annoying (you have to wait 10s on stop –or specify a timeout, you can't use restart, etc) and seen only with kiwix-serve. I don't know what's going on but maybe catching signals on kiwix-serve and calling Server::stop() would help ?

Note: I am using it with a full command and not a bash shortcut. PID is 1.

[mgautierfr]

I would say that kiwix-serve should behave (if specified in command line) as a standard (and correctly implemented) daemon.
We already have a --daemon option but it is far from a correct daemonization of the process.

https://www.freedesktop.org/software/systemd/man/daemon.html explain pretty well what need to be implemented.
I would go to totally implement (at least) the new style daemon. Old style daemon is a bit more tricky to implement.

Implementing new style daemon implies to correctly handle SIGTERM to exit cleanly and SIGHUP to reload config (#243)

[kelson42]

@veloman-yunkan Would you be able to implement this ticket? Do we things which are unclear before implementation?

[veloman-yunkan]

@veloman-yunkan Would you be able to implement this ticket? Do we things which are unclear before implementation?

I will look at it this week.