November 19th, 2009 · Linux, OS X
This is the promised launchd script to run the service in an earlier post.
The name of this file is /Library/LaunchDaemons/com.{domain_name}.{service_name}.plist
Replace any text in curly braces {} with some appropriate information for your script.
When you are finished creating the file, load it with:
launchctl load -w /Library/LaunchDaemons/com.{domain_name}.{service_name}.plistIt should crank right up and start doing its’ thang.
Here’s the content of the .plist file:
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| <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Enabled</key>
<true/>
<key>GroupName</key>
<string>staff</string>
<key>KeepAlive</key>
<true/>
<key>Label</key>
<string>com.{domain_name}.{service_name}</string>
<key>Program</key>
<string>/usr/local/bin/{script_name}</string>
<key>ProgramArguments</key>
<array>
<string>{script_name}</string>
<string>start</string>
<string>--nofork</string>
</array>
<key>QueueDirectories</key>
<array/>
<key>RunAtLoad</key>
<true/>
<key>ServiceDescription</key>
<string>Some creative description of your service.</string>
<key>UserName</key>
<string>{user_name}</string>
<key>WatchPaths</key>
<array/>
</dict>
</plist> |
Tags:
November 9th, 2009 · Linux, OS X
This is a daemon script written for OS/X in bash. It can be run either as a daemon or a launchd service. The launchd service file will follow in a later post.
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| #!/bin/bash
# put these lines in the file header comment
# FILE: |FILENAME|
# USAGE: ./|FILENAME| start [ stop | restart ] [ --nofork ] [ --debug ]
#-----------------------------------------------------------------------
#Uncomment the following line to echo all commands to the terminal
#-----------------------------------------------------------------------
#set -x
# better yet, set the --debug command line flag and syslog it.
#-----------------------------------------------------------------------
# Check number of command line arguments
#-----------------------------------------------------------------------
[[ $# -lt 1 ]] || [[ $# -gt 3 ]] && {
echo -e "\tUsage: ${0##/*/} start [ | stop | restart ] [ --nofork ] [ --debug ]"
exit 1
}
#A launchd script in OSX is not supposed to fork
nofork=`echo "$*" | grep "\-\-nofork"`
[[ ! -z $nofork ]] && nofork=true
[[ -z $nofork ]] && nofork=false
#check to send everything to syslog
debug=`echo "$*" | grep "\-\-debug"`
[[ ! -z $debug ]] && debug=true
[[ -z $debug ]] && debug=false
#configuration
basename="`basename $0 .sh`"
# look for the conf file in the same folder as the script
conf="`dirname $(which $0)`/${basename}.conf" #<-- which handles "bash -x $0 start"
[[ -f "$conf" ]] && source "$conf"
whoiam=`whoami`
# create a pid file with the pid of the process on the first line
pidfile="/tmp/${basename}.pid"
[[ $whoiam == 'root' ]] && pidfile="/var/run/${basename}.pid"
#find the temp directory
tempfile=`mktemp -t j`
#put all of your incidentals in the tempdir
tempdir=`dirname $tempfile`
rm $tempfile
#Do all further processing from the root
cd /
# Load the daemon template for OSX
. /etc/rc.common
#traps trap 'source $conf' 1
# response to kill -s HUP $$ should be to read the config file.
#trap 'echo trap 0; rm -f "$pidfile"; exit' 0 #can't trap this, daemon will exit when parent dies.
trap 'echo trap 3; rm -f "$pidfile"; exit' 3 15 #clean up the pidfile
[[ "$debug" == "true" ]] && trap 'logger -t $0 -i -- $USER : $BASH_COMMAND' DEBUG #syslog everything if we're debugging
trap 'logger -t $0 -i -- $USER : $BASH_COMMAND' ERR #log errors regardless
#=== FUNCTION ================================================================
# NAME: main
# DESCRIPTION: Allows daemon to be run in background
# PARAMETERS: none
# RETURNS: void
#===============================================================================
function main() {
# Put your service code here
while : # Loop forever
do
sleep 10
echo $RANDOM
done
}
#=== FUNCTION ================================================================
# NAME: StartService
# DESCRIPTION: implements function from /etc/rc.common
# PARAMETERS: none
# RETURNS: void
#===============================================================================
StartService () {
CheckForNetwork
[[ -f $pidfile ]] && {
pid=`head -n 1 $pidfile`
procname=`ps awx | awk "\\\$1 == $pid { print \\\$7 }"`
[[ ! -z $procname ]] && [[ "$procname" == "$0" ]] && {
echo "$basename is already running"
exit 1
}
rm $pidfile
}
# do the service
# no fork method for launchd service
[[ "$nofork" == "true" ]] && {
#pid file with this process id
echo $$ > $pidfile
main
exit
}
# fork and exit
main &
# create a pid file with the pid of the child
# the parent will go away and leave the child owned by init
echo $! > $pidfile
}
#=== FUNCTION ================================================================
# NAME: StopService
# DESCRIPTION: implements the function from /etc/rc.common
# PARAMETERS: none
# RETURNS: void
#===============================================================================
StopService ()
{
[[ -f $pidfile ]] && {
kill `head -n 1 $pidfile`
rm $pidfile
}
#touch "$quit"
}
#=== FUNCTION ================================================================
# NAME: RestartService
# DESCRIPTION: implements the function from /etc/rc.common
# PARAMETERS: none
# RETURNS: void
#===============================================================================
RestartService ()
{
StopService
StartService
}
#-------------------------------------------------------------------------------
# Call the function declared in /etc/rc.common to daemonize process
#-------------------------------------------------------------------------------
RunService "$1" #First parameter is start/stop/restart |
Tags: os/x mac bash daemon script
October 30th, 2009 · Linux, OS X
Problem: You want your script to execute without overlapping another execution.
Solution: Make a flag file so you know that your script is already executing.
Extended problem: What if your script dies and leaves the flag file behind?
Extended solution: Check the process list to see if the old instance is still alive.
Ext. Ext. Problem: What if somebody kills my script?
Ext. Ext. Solution: Trap the abnormal exit and clean up properly.
Ext. Ext. Ext. Problem: What if someone else is invoking a script with exactly the same name as mine?
Ext. Ext. Ext. Solution: You’re screwed. Give your script a really long descriptive name so this won’t happen.
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| #figure out where to put the pid file
myfile=`basename "$0" .sh`
whoiam=`whoami`
pidfile=/tmp/$myfile.pid
[[ "$whoiam" == "root" ]] && pidfile=/var/run/$myfile.pid
#remove the pid file cleanly on exit
function cleanup () {
[[ -f "$pidfile" ]] && rm "$pidfile"
#add other post processing cleanup here
}
# trap all the exit signals for cleanup
trap "cleanup; exit" 0 SIGINT SIGQUIT SIGTERM # ON OS/X this is 0 2 3 15
# Am I already running?
[[ -f "$pidfile" ]] && {
#pidfile exists, check if previous process exists.
pid=`head -n 1 $pidfile`
pidtest="\$1 == $pid { print \$7 }"
procname=`ps awx | grep $0 | awk "$pidtest"`
[[ "$procname" == "$0" ]] && {
echo "Running"
exit 1
}
}
#put this pid in the file
echo $$ > "$pidfile" |
Tags: bash shell script pid
