Re: Bug#170677: ITP: launchtool -- Run a command supervising its execution

[Enrico Zini <enrico@debian.org>]

On Mon, Nov 25, 2002 at 03:45:53PM +0100, Christian Surchi wrote:

> > * Package name    : launchtool
> > Run a user-supplied command supervising its execution in many ways,
> > such as controlling its environment, blocking signals, logging its
> > output, changing user and group permissions, limiting resource usage,
> > restarting it if it fails, running it continuously, turning it into
> > a daemon and more.
> 
> So, is it different from the *simple* "daemon" the we have already in
> the archive? And maybe it's not a PITA like "run"! ;-)

It's quite similar to daemon.  They have similar features, some are
better in daemon, some are better in launchtool.  It has features
similar to start-stop-daemon, as well.  It can probably replace both, or
be replaced by one of them in most situations.

However, launchtool is not intended to only run daemons: you can run a
shellscript normally, but with its output sent to the logs with the
given priority, for example.

You can also create an executable configuration file for launchtool and
use it as a wrapper around another command.

I include some examples taken from the manpage, to give an idea of how
it works and of some intended scenarions of usage:

# Run a command normally
launchtool -t tag 'echo "Hello, world!"'

# Run a command restarting it if it fails:
launchtool -t tag --wait-times=1,1,1,3,3,3,10,10,10 'my_wonderful_server'

# Run a command, with restrictions, restarting it if it fails, as a
# daemon
launchtool -t myserver -d --user=myserver --chroot=/var/myserver \
	--limit-process-count=5 --limit-open-files=10 \
	--wait-times=1,1,1,3,3,3,10,10,10 \
	--infinite-runs --stats \
	--log-launchtool-output=syslog:myserver,LOG_DAEMON,LOG_INFO \
	--log-launchtool-errors=syslog:myserver,LOG_DAEMON,LOG_ERR \
	--log-child-output=syslog:myserver,LOG_DAEMON,LOG_INFO \
	--log-child-errors=syslog:myserver,LOG_DAEMON,LOG_ERR \
	'my_experimental_server'

# Same thing, using a configuration file
tag = myserver
command = my_wonderful_server
daemon = yes
stats = yes
user = myserver
root dir = /var/myserver
process count limit = 5
open files limit = 10
wait times = 1,1,1,3,3,3,10,10,10
infinite runs = yes
launchtool output = syslog:myserver,LOG_DAEMON,LOG_INFO
launchtool errors = syslog:myserver,LOG_DAEMON,LOG_ERR
command output = syslog:myserver,LOG_DAEMON,LOG_INFO
command errors = syslog:myserver,LOG_DAEMON,LOG_ERR 

# Transform a shell command in a polling daemon that ensures that the
# file /tmp/have_mobile exists only if my cell phone is present in the
# IRDA discovery list
launchtool -t celldetect -d --silent-restart-time=5 --silent-restart-status=0 --user=nobody \
	"if grep -q SIEMENS /proc/sys/net/irda/discovery; then touch /tmp/have_mobile; else rm -f
/tmp/have_mobile; fi ; exit 0"

# Ceck if the celldetect daemon is running
launchtool -t celldetect --check

# Kill the celldetect daemon launched with the command above
launchtool -t celldetect -k

# Same polling daemon, with an executable configuration file

#!/usr/bin/launchtool -C
tag = celldetect
command = if grep -q SIEMENS /proc/sys/net/irda/discovery; then touch /tmp/have_mobile; else rm -f /tmp/have_mobile; fi ; exit 0
daemon = yes
user = nobody
silent restart time = 5
silent restart status = 0

# Check if the celldetect daemon is running, using the executable
# configuration file
celldetect --check

# Kill the celldetect daemon using the executable configuration file
celldetect -k


And, no, it does not intend to be a PITA like run. :-)

Bye, Enrico