cups 打印服务器：如何保留本地和远程作业直到释放？

我没有找到杯子的配置选项，该选项确实将每个传入的打印作业设置为暂停。我编写了一个 bash 脚本来完成这项工作：

#!/bin/bash

# cups_hold_new_jobs [<printer>]

# Resume a cups printer, set all queued and newly incoming jobs on
# hold, pause printer and exit.

# Runs as long as there are jobs in the print queue. Start from cron.

DEBUG=false


# --------- do not edit below ---------
VERSION=0.3
VERSION_INFO="(c) 2024 by Adrian Zaugg under GNU General Public License Version 3."

# initiate job list
declare -a JOBS

# set defaults
LOCK="/run/$(basename "$0")"
LOCKED=false
OWNPIDPPID="$$  $PPID   "


# get job list
function get_job_list() {
    JOBS=($(lpstat -o "$PRINTER" | sed -e 's/^\('"$PRINTER"'-[0-9]\+\).*$/\1/g'))
}


# DEBUG variable must be set to true or false
if [[ "$DEBUG" != "true" && "$DEBUG" != "false" ]]; then
    DEBUG=false
fi

# cups must be running
if [ $(lpstat -r | grep -c "is running") -eq 0 ]; then
    $DEBUG && echo "[INFO] CUPS is not running. Nothing to do." >&2
    exit 0
fi

# get printer (or class?)
PRINTER="$1"

# get default printer if none was given as an argument or check given printer name
if [ -z "$PRINTER" ]; then
    PRINTER="$(lpstat -p -d 2>/dev/null | grep "^system default destination: " | sed -e 's/^system default destination: //')"
    # check
    if [ -z "$PRINTER" ]; then
        echo "[ERROR] No printer given on command line and unable to detect default printer." >&2
        exit 1
    else
        $DEBUG && echo "No printer given on command line, using default printer: $PRINTER" >&2
    fi
else
    # no space, hash, slash or newline in printer names allowed
    PRINTER="$(echo "$PRINTER" | head -1 | sed -e "s%/.*$%%" -e "s/#.*$//" -e "s/ .*$//")"
    if [ ${#PRINTER} -lt ${#1} ]; then
        echo "[ERROR] Disallowed characters in printer name found."
        exit 1
    fi

    # check given printer exists
    ERR="$(lpstat -p "$PRINTER" 2>&1)"
    if [ $? -ne 0 ]; then
        # printer does not exist or other error
        echo "[ERROR] No printer printer \"$PRINTER\" found." >&2
        exit 1
    else
        $DEBUG && echo "Using printer: $PRINTER" >&2
    fi
fi

# lock
while ! $LOCKED; do
    mkdir "$LOCK" 2>/dev/null
    if [ $? -eq 0 ]; then
        LOCKED=true
        break;
    elif [ $(ps -e -o pid,ppid,command | sed -n "s/\([0-9]\{1,\}\)[^0-9]\{1,\}\([0-9]\{1,\}\)[^0-9]\(.*\)$/\1\t\2\t\3/p" | \
             grep -v "$OWNPIDPPID" | grep -cE 'bash .*/'"$(basename "${0}")"'$') -gt 1 ]; then
        # process already started
        $DEBUG && echo "Another instance of this script is already running." >&2
        exit 0
    else
        # stale lock, remove it
        rmdir "$LOCK" 2>/dev/null
        if [ $? -ne 0 ]; then
            echo "[ERROR] Removing stale lock $LOCK failed." >&2
            exit 1
        else
            $DEBUG && echo "Removed stale lock." >&2
        fi
    fi
done

# pause printer
if [ $(lpstat -p "$PRINTER" | grep -c -m 1 "$PRINTER disabled") -eq 0 ]; then
    cupsdisable "$PRINTER"
    $DEBUG && echo "Printer paused." >&2
fi
PRINTER_PAUSED=true

# loop as long as there are jobs in the queue
get_job_list
until [ ${#JOBS[@]} -eq 0 ]; do

    # find index of last held job in new job list
    last_held_job_index=0
    unset job_id
    while [[ "${JOBS[$last_held_job_index]}" != "$last_held_job_id" && $last_held_job_index -le ${#JOBS[@]} ]]; do
        last_held_job_index=$(($last_held_job_index+1))
    done
    if [ $last_held_job_index -eq ${#JOBS[@]} ]; then
        # job not found
        last_held_job_index=-1
    fi

    # set newly queued jobs on hold
    i=0
    for job_id in ${JOBS[@]}; do
        # compare index to marker of last held index
        if [ $i -gt $last_held_job_index ]; then
            # set job on hold
            ERR="$(lp -i "$job_id" -H hold 2>&1)"
            if [ $? -eq 0 ]; then
                echo -e "[INFO] holding job $job_id" >&2
            else
                echo "[ERROR] Failed to hold job \"$job_id\": $ERR" >&2
            fi
            # remember last index
            last_held_job_index=$i
        fi
        i=$(($i+1))
    done
    last_held_job_id="${JOBS[$last_held_job_index]}"

    # wait a bit
    sleep 1

    # reread jobs in print queue
    get_job_list

    # enable printer now
    if $PRINTER_PAUSED; then
        cupsenable "$PRINTER"
        PRINTER_PAUSED=false
    fi
done

# queue is now empty disable printer
if $PRINTER_PAUSED; then
    $DEBUG && echo "Queue is empty." >&2
else
    cupsdisable "$PRINTER"
    echo "[INFO] Queue is empty now, pausing printer $PRINTER." >&2
fi

# unlock
if $LOCKED; then rmdir "$LOCK"; fi

exit 0

该脚本在启动时暂停打印机，将所有现有作业设置为暂停，对新传入的作业执行相同的操作，取消暂停打印机并等待队列变空。退出后，它会再次暂停打印机。

这个想法是，打印作业可以由其所有者手动释放或取消（或通过杯子设置 MaxHoldTime 自动取消）。这是简单拉式打印系统的一部分。

这是脚本的第一个版本，它在竞争条件下受到影响，必须由 cron 调用，缺少帮助文本，未针对类、asf 进行测试。如果我添加功能或修复，我将在此答案中发布下载链接。使用它由您自己负责。不要在生产中使用，它在这里给出一个如何完成的想法。

如果能听到一种更简单的方法来告诉cups将所有传入的作业暂停以建立一个跟随我的打印系统而不需要大量的附加软件，那就太好了。

下载：复制上述内容失败，因为选项卡可能会丢失，请使用下载链接：https://ente.limmat.ch/ftp/pub/software/bash/cups/