Re: Option for runsv/runsvdir to specify how many times to restart a service in a certain time period before giving up?

[Alex Efros <powerman@powerman.asdfGroup.com>]

Hi!

On Mon, Oct 30, 2006 at 02:58:34PM +0100, Laurent Bercot wrote:
>  Another approach to the throttle feature that doesn't require notification
> from runit would be to have a short-lived program, designed to be called in
> the finish script, that stores its information (last calling time ans such)
> in the filesystem. Maybe it's what you were thinking about. But I'm not

Yep, I'm thinking this way.

> sure how to make it reliable; storing short-lived information in the
> filesystem is very error-prone, that's the .pid way, which is precisely
> what supervision tools were designed to avoid.

I don't see any troubles making it reliable. DJB show how to develop
reliable shell scripts long time ago: use atomic operations like 'mv'
for updating files.

    # reliable counter in bash
    prev=$(< .counter )
    next=$(( $prev + 1 ))
    echo $next > .counter.$$
    mv .counter.$$ .counter

For this task we need something more complex than just counter because we
should count restarts for some time interval, but this also can be done in
reliable way.

P.S. If my script die before `mv` it can leave .counter.$$ file on disk.
If this important we can add cleanup code. If it's important to not run 2
such scripts simultaneously, then we can use something like `chpst -l`.
Etc... Reliable shell scripts is reality, let's face it. ;-)

-- 
			WBR, Alex.