Ubic - how to implement your first service

I had a hidden agenda when I asked on this blog about how do you run your daemons.

There is a tool I recently opensourced. It can be compared to classic SysV init script system or to daemontools, runit or upstart, but it already is better and more flexible at least in some of its properties (otherwise I wouldn't bother to implement it :) ).

It is called Ubic and it is a toolkit for describing daemons in pure perl.

Ubic service is simply a perl object of some class inherited from base Ubic::Service class.
Ubic loads service descriptions from /etc/ubic/service/ directory.
To create your first service, you have to write something like this:


# cat >/etc/ubic/service/test
use Ubic::Service::SimpleDaemon;
return Ubic::Service::SimpleDaemon->new({ bin => "sleep 1000" });

"ubic status" command can show you status of all or some services on host:


# ubic status
test off
ubic-ping running
# ubic status test
test off

Now, as you probably already guessed, to start service you simply have to say "ubic start":


# ubic start test
Starting test... started
# ubic status
test running

What are you getting for free with this simple example?


  • ubic-watchdog - generic program that runs every minute from cron and checks every service; when 1000 seconds of sleep will be over, this 'test' service will be restarted automatically;

  • LSB compliance (it is strange how many /etc/init.d/ services even on latest Ubuntu distributions can't handle double start correctly and don't implement status check);

  • Neat colors :) You can't see them in examples above, but they are there;

  • HTTP ping service:

    # wget -q -O - 'http://localhost:12345/status/service/test'
    ok

    If you don't need it, you can always turn it off with 'ubic stop'. Or you can try to read /etc/ubic/service/ubic-ping for spoilers about more complex ubic features :)


By this point in my story:
- init.d people should already think that ubic is cool ;)
- daemontools/runit users will probably require more persuading, so I'm going to continue tomorrow.

PS: Installation note: please read "installation" section in README.md file before installing.

PPS: There is a mailing list, don't hesitate to join and ask your questions.

PPPS: This is my first opensource module which i'm trying to attract attention to, so any meta-advices from guys with tons of popular CPAN distributions about what i'm doing right/wrong or how else can I persuade anyone to try ubic are very welcome too :)

4 Comments

Any thoughts on upstart and systemd?

How can I make Ubic service to run at system startup? :)

Leave a comment

About Vyacheslav Matyukhin

user-pic I blog about Perl.