mkqueue.sh

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#!/bin/zsh
#
# \author mdejong
#
script=${0##*/}

# ----------------------------------------------------------------------------------------
# Simple desktop batch queue processor.
#
# The batch queue is defined by a standard FIFO and
# the entries in the queue are processed line-by-line.
# Each entry is executed as a separate process in the background,
# commonly referred to as a job.
# The number of jobs that can simultaneously run is limited by the queue size.
# The batch queue can be terminated by submitting a job with contents "exit".
#
# The batch queue may also be an existing regular file.
# The entries in the queue are processed as normal but
# the batch queue will terminate when the end-of-file is reached.
#
# A job can be submitted using the puts_queue function (see qlib.sh or qlib.csh).
# A series of joint commands can be submitted using a sequence of
# calls to put_queue, terminated by a single puts_queue call.
# ----------------------------------------------------------------------------------------

if [ -z $JPP_DIR ]; then
    echo "Variable JPP_DIR undefined."
    exit
fi

source $JPP_DIR/setenv.sh $JPP_DIR >& /dev/null
source qlib.sh

set_variable:  DEBUG       MKQUEUE_DEBUG  3
set_variable   QUEUE_NAME  /tmp/queue     # default name of queue  
set_variable   QUEUE_SIZE  1              # default size of queue  
set_variable   COMMAND     mkqueue.sh     
set_variable   SLEEP_TIME  1s             # sleep time  

if do_usage $*; then
    print -u2 "$script [queue name [queue size]] <option>"
    print -u2 "Possible options: start, stop, continue, restart."
    exit
fi

case $# in
    3)  set_variable QUEUE_SIZE  $argv[2];&
    2)  set_variable QUEUE_NAME  $argv[1];&
    1)  set_variable OPTION      $argv[-1];;
    *)  fatal "Wrong number of options.";;
esac

if ( is_CCLyon ); then
    fatal "This batch queue processor is intended for use on a desktop."
fi

if (( $QUEUE_SIZE < 1 )); then
    fatal "Invalid queue size $QUEUE_SIZE."
fi

if   [[ $OPTION != "start" && $OPTION != "stop" && $OPTION != "continue" && $OPTION != "restart" ]]; then
    fatal "Invalid option $OPTION."
fi

if   [[ $OPTION == "stop" || $OPTION == "restart" ]]; then

    PID=(`get_pid $COMMAND`)

    PID[$PID[(i)$$]]=
    
    if [[ -n $PID ]]; then 
        notice "Stop $COMMAND."
        kill -9 $PID
    fi
    
    rm -f $QUEUE_NAME                                     # remove FIFO
    
    OPTION=${OPTION/restart/start}

elif [[ $OPTION == "continue" ]]; then
    
    PID=(`get_pid $COMMAND`)
    
    PID[$PID[(i)$$]]=

    if [[ -n $PID ]]; then 
        notice "$script is running with PID(s) $PID"
    else
        OPTION=start
    fi

fi

if [[ $OPTION = "start" ]]; then

    notice "Start batch queue ${QUEUE_NAME} >& ${QUEUE_NAME}_log"

    trap "" HUP                                           # trap hangup
    
    queue $QUEUE_NAME $QUEUE_SIZE $SLEEP_TIME >& ${QUEUE_NAME}_log &

    while [[ ! -e $QUEUE_NAME ]]; do
        sleep $SLEEP_TIME
    done

fi