Automatically render PDFs from dot files. A filesystem notifier is watching a directory; once a dot file is created within this directory, this script will fully automatically create the corresponding PDF file and display it using the standard PDF viewer on your system. Note that this script is platform dependent (MAC OSX). However, by exchangin…

render.sh

#!/bin/bash

INPUT_DIR="/tmp/spool/in"
OUTPUT_DIR="/tmp/spool/out"
DELAY=4
PIDFILE="/tmp/workdog.pid"

FIFO="/tmp/render.fifo"
LOGGING="stdout"


function createDir() {
    [ ! -d "${1}" ] && mkdir -p "$1"
}

function cleanup(){
    info "${FUNCNAME[0]}" "cleanup called"
    [ -e "$FIFO" ] && rm $FIFO
    return 0
}

function log(){
    local fun=''
    fun="$(basename "$0")"
    logger -t "$fun" "$1"
}

function info(){
    local output="info: $1 : $2"
    [ "$LOGGING" == "stdout" ] || [ "$LOGGING" == "all" ] && echo >&1 "$output"
    [ "$LOGGING" == "file" ] || [ "$LOGGING" == "all" ] && log "$output"
}

function error(){
    local output="error: $1 : $2"
    [ "$LOGGING" == "stdout" ] -o [ "$LOGGING" == "all" ] && echo >&2 "$output"
    [ "$LOGGING" == "file" ] -o [ "$LOGGING" == "all" ] && log "$output"
}

function fileaction() {
    local file=''
    local ftype=''
    local filename=''
    file="$1"
    ftype="$(file -b --mime-type "$1")"
    info "${FUNCNAME[0]}" "$ftype"
    [ "$ftype" == "text/plain" ] && {
      info "${FUNCNAME[0]}" "fileaction on $file"
      filename="$(basename "$file")"
      filename="${filename%.*}"
      local outfile="${OUTPUT_DIR}/${filename}.pdf"
      info "${FUNCNAME[0]}" "generate outfile $outfile"
      dot -T pdf "$file" -o "$outfile" && open "$outfile"
    }
}

function main(){
    if [ ! -e "$FIFO" ]
    then
        mkfifo "$FIFO"
    fi
    createDir "$INPUT_DIR"
    createDir "$OUTPUT_DIR"

    fswatch --event Created --event Updated  "$INPUT_DIR" > "$FIFO" &

    echo $! > $PIDFILE
    info "${FUNCNAME[0]}" "write PID ($!) to file"
    trap cleanup EXIT TERM INT

    while read -r file; do
        info "Fileaction $file"
        fileaction "$file"
        sleep $DELAY
    done < $FIFO

    cleanup
    return 0
}


USAGE="$0 [start|stop]"

case $1 in
    start)
        main
        ;;
    stop)
        cleanup
        kill -9 "$(cat $PIDFILE)"
        ;;
    *)
        echo "$USAGE"
        exit 1
    ;;
esac

exit 0