a wrapper to handle graceful lock breaking (when needed) of golock programs

run-exclusive.sh

#!/bin/zsh

# call like:
# $ run-exclusive.sh /path/of/progname /path/of/lockfile
# e.g.
# $ run-exclusive.sh ./testlock t.lock

# clearly you want progname to be something that will only match once.
# don't use a short string that is a substring match of something else running
export PROGNAME=$1

# GOLOCKNAME is an env var that is hardcoded into the golock package. the lock 
# file name MUST be assigned to an env var with this name. when running 
# correctly, $PROGNAME will open a file called $GOLOCKNAME and get
# an exclusive lock on it. 
export GOLOCKNAME=$2

echo "running: $PROGNAME with golock lock file $GOLOCKNAME"

# if the lockfile exists, break it (rm -f) if there is no other 
# copy of $PROGNAM running or if there is a copy of it running as a zombie
if [ -e $GOLOCKNAME ]; then
    echo "lockfile $GOLOCKNAME found"
    MATCHRUN=`ps -e -o pid,stat,cmd | grep -v grep | grep $PROGNAME | cut -d" " -f3 -`
    NUMMATCHES=`echo $MATCHRUN | wc -l`
    BROKELOCK="no"
    if [ $NUMMATCHES '==' "1" ]; then
        # *this* script was the only match
        echo "no other $PROGNAME running..."
        rm -f $GOLOCKNAME
        BROKELOCK="yes"
    else 
        for i in $MATCHRUN; do
            if [ $i '==' "Z" ]; then
                echo "zombie found..."
                rm -f $GOLOCKNAME
                BROKELOCK="yes"
                break
            fi
        done
    fi
    # rm -f wouldn't remove the lock file if the permissions were wrong
    if [ $BROKELOCK '==' "yes" ]; then
        if [ -e $GOLOCKNAME ]; then
            echo "did not break the lock, see user/group ownership of $GOLOCKNAME"
        else 
            echo "broke the lock"
        fi
    else 
        echo "lock appears legit"
    fi
fi

exec $PROGNAME