Generic logging run script

[Robin Bowes <robin-lists@robinbowes.com>]

Hi all,

I've taken some of the ideas/suggestions from this thread and come up 
with this generic logging script.

I've written it to use /etc/sysconfig/ for configuration, as I work 
mainly on RH-flavour distributions and that's what they use.

To use:

1. Save the script somewhere and chmod +x
2. symlink the script into your services' log dir

By default it will run as user $SVNAME and log to dir /var/log/sv/$SVNAME

If you want to change this, either for all services, or for just one 
service, you'll need to create the following dir structure:

   mkdir -p /etc/sysconfig/sv/default/log/

Then for each of your services:

   mkdir -p /etc/sysconfig/sv/$SVNAME/log/

To change something for all services:

   echo "LOGPARENT=/var/log" > /etc/sysconfig/sv/default/log/settings

To change something for just one service:

   echo "LOGUSER=dnslog" > /etc/sysconfig/sv/dnscache/log/settings
   echo "LOGUSER=dnslog" > /etc/sysconfig/sv/tinydns/log/settings

If you want to use something other than the standard svlogd logging 
configuration, create a config file:

cat > /etc/sysconfig/sv/default/log/config << EOCONFIG
s2000000
n20
EOCONFIG

Or for a specific service:

cat > /etc/sysconfig/sv/tinydns/log/config << EOCONFIG
s4000000
n50
EOCONFIG

As always, I'd appreciate any comments/suggestions.

Here's the script:

#!/bin/sh

# This is a generic logging script services using runit/svlogd
#
# The service configuration is taken from the following files:
#   /etc/sysconfig/sv/$SVNAME/log/settings
#   /etc/sysconfig/sv/default/log/settings
#
# The following ENV vars can be set in the "settings" files:
#    LOGPARENT - log dir will be set to $LOGPARENT/$SVNAME
#    LOGDIR    - full path. If specified, over-rides $LOGPARENT
#    LOGUSER   - user the logging process should run as
#
# The service-specific files are used in preference to the defaults.
#
# If no settings files are found, the logging service will run as user
# $SVNAME and write to "/var/log/sv/$SVNAME"
#
# The behaviour of the svlogd is controlled by a file $LOGDIR/config.
# This file is copied from:
#   /etc/sysconfig/sv/$SVNAME/log/config
#   /etc/sysconfig/sv/default/log/config
#
# The service-specific files are used in preference to the defaults.
#
# If no config files are found, svlogd defaults are used.
#
# Copyright (c) 2008 by Robin Bowes <robin@robinbowes.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# Get the name of the service this log belongs to
SVNAME=$(basename $(dirname $(readlink -f .)))

# Where to look for configuration settings
CFGBASE=/etc/sysconfig/sv

# cp is aliased to "cp -i" on some distros
cp="/bin/cp"

# Get defaults for logging and this service log
[ -r "${CFGBASE}/default/log/settings" ] && \
   . "${CFGBASE}/default/log/settings"
[ -r "${CFGBASE}/${SVNAME}/log/settings" ] && \
   . "${CFGBASE}/${SVNAME}/log/settings"

# Set LOG_PARENT, LOGUSER and LOGDIR to default values if not set already
LOGUSER=${LOGUSER:-$SVNAME}
LOGPARENT=${LOGPARENT:-/var/log/sv}
LOGDIR=${LOGDIR:-"$LOGPARENT/${SVNAME}"}

# make sure log parent exists
[ -d "${LOGPARENT}" ] || exit 1 ]

# Make sure the log dir exists
[ -d "${LOGDIR}" ] || mkdir "${LOGDIR}" || exit 1

# Configure logging. Check for sv-specific then default config
if [ -r "${CFGBASE}/${SVNAME}/log/config}" ]; then
   ${cp} "${CFGBASE}/${SVNAME}/log/config}" "${LOGDIR}/config"
elif [ -r "${CFGBASE}/default/log/config}" ]; then
   ${cp} "${CFGBASE}/default/log/config}" "${LOGDIR}/config"
fi

# Set ownership on the log dir
chown -R ${LOGUSER} "${LOGDIR}"
# reset perms on log config file, if it exists
[ -r "${LOGDIR}/config" ] && chown root "${LOGDIR}/config"
# Set perms on the log dir
chmod 750 "${LOGDIR}"
chmod g+s "${LOGDIR}"

# Now run the log process
exec chpst -u "${LOGUSER}" svlogd -tt "${LOGDIR}"