Re: Who actually gets the TERM signal in "runsvctrl down"?

[Lloyd Zusman <ljz@asfast.com>]

Charlie Brady <charlieb-smarden-supervision@budge.apana.org.au> writes:

> On Fri, 25 Jun 2004, Lloyd Zusman wrote:
>
> [ ... ]
>
>> By "right things" I mean (for apache):
>> 
>>   runsvctrl up apache      =>    invoke "apachectl start"
>>   runsvctrl down apache    =>    invoke "apachectl stop"
>
> Why do you say they are the "right things"? Please re-read my previous 
> message. runsv can already do what "apachectl" does, but more reliably, 
> and using less resources. Why do you insist on using apachectl?

See below.


>> I don't want to send a TERM signal to httpd in order to stop it, because
>> I want it to shut down using the same logic that "apachectl stop" uses,
>> which is definitely not to simply send a TERM signal to the httpd
>> daemon.
>
> No, that's just what "apachectl stop" does.

Here's the code fragment within "apachectl" on my system that
handles the "stop" argument:

  case $ARGV in
  start|stop|restart|graceful)
      $HTTPD -k $ARGV
      ERROR=$?
      ;;
      ... etc. ...
  esac

Therefore, an "apachectl stop" causes "httpd -k stop" to be invoked.
Does passing "-k stop" to httpd cause it to signal itself with
TERM?  If so, can we count on that in all versions of apache?

This is Apache 2.0.48, by the way, in case that makes any difference.


>> [ ... ]
>
> Why do you want this extra shell process between runsv and apache, and
> why do you want to run apachectl?

Because I want to use the software's own recommended startup and
shutdown procedures when I invoke it and kill it.  It might be that in
the specific case of apache, I can safely strip out all of the wrapper
stuff that its startup script (apachectl) provides, but in the general
case, I can't always count on this working.  I'd rather rely on startup
and shutdown scripts that are supplied with the various software
packages that I use.  But I want to control them via runit mechanisms.

The amount of extra time that is used to start up and stop a
long-running daemon like apache by invoking its recommended wrapper
script inside of "run" is infinitessimal in relation to the daemon's
lifetime.


> [ ... ]
>
>> > For "apachectl stop", just do "runsvctrl down apache". For "apachectl 
>> > graceful", do "runsvctrl 1 apache; raunsvctrl u apache". For "apachectrl 
>> > restart", do "runsvctrl t apache; raunsvctrl u apache". Etc.
>
> You now just need a run script which does:
>
> #! /bin/sh
> exec httpd ......
>
> with the correct args.

-- 
 Lloyd Zusman
 ljz@asfast.com
 God bless you.