获取gphoto2的当前状态

Question

我运行带有--wait-event-and-download参数的gphoto，以便将使用红外遥控器拍摄的照片保存到计算机中。

我设置了第二个脚本来中断等待过程并以编程方式拍摄照片，如下所示：

#!/bin/sh
# shootnow.sh - stop the current gphoto2 process (if it exists),
# shoot a new image, then start a new wait-event process.

pkill -INT gphoto2     #send interrupt (i.e. ctrl+c) to gphoto2
sleep 0.1              #avoid the process ownership error
gphoto2 --capture-image-and-download  #take a picture now
gphoto2 --wait-event-and-download   #start a new wait-event process

但是我想确保在中断之前，当前的第一个等待事件过程没有下载图像（这会导致混乱的情况，即图像填满了相机的内存，从而阻止了进一步的操作）。 所以第二个脚本应该更像这样：

#!/bin/sh
# shootnow-with-check.sh - stop the current gphoto2 process (if it exists 
# and isn't currently downloading an image), shoot a new image, then start 
# a new wait-event process.

shootnow() {  # same as previously, but now in a function
    pkill -INT gphoto2
    sleep 0.1
    gphoto2 --capture-image-and-download
    gphoto2 --wait-event-and-download
}

if [ ***current output line of gphoto2 process doesnt start with "Downloading"*** ] then
    shootnow
else
    echo "Capture aborted - a picture was just taken and is being saved."
fi

如果声明，有人可以帮我吗？ 我可以读取正在运行的gphoto进程的当前输出行吗？

Answer 1

我最终使用如下脚本来管理：

#!/bin/bash
# gphoto2-expect.sh
# use expect to monitor gphoto2 during --capture-image-and-download with
# --interval=-1, adding in SIGUSR1 functionality except during a
# download event.

echo "Prepping system for camera"
killall PTPCamera
expect << 'EOS'
puts "Starting capture..."
if [catch "spawn gphoto2 --capture-image-and-download --interval=-1" gp_pid] {
  Log $ERROR "Unable to start gphoto2.\n$gp_pid\n"
  return 0
}

trap {exec kill -SIGUSR1 $gp_pid} SIGUSR1
set timeout -1
expect {
  -i $spawn_id
  "Downloading" {
    trap {send_user "\n Ignoring request as currently downloading"} SIGUSR1 ; exp_continue
  }
  "Saving file as" {
    sleep 0.1
    trap {exec kill -SIGUSR1 $gp_pid} SIGUSR1 ; exp_continue
  }
}

EOS

可以用另一个脚本触发：

#!/bin/bash
# trigger.sh - trigger an immediate capture
var=$(pidof expect)
kill -SIGUSR1 "$var"

Answer 2

gphoto2有一个选项--hook-script FILENAME。 FILENAME必须是一个可执行脚本，并在某些gphoto2事件上被调用。 然后，脚本具有一个环境变量ACTION，您可以将其用于您的目的。 例如：您使用以下命令调用gphoto2

gphoto2 --capture-image-and-download --hook-script myhook.sh

和myhook.sh看起来像

#! /bin/bash
echo $ACTION

那么myhook.sh将被调用4次。 它的输出是

init
start
download
stop

有关详细信息，请参见man gphoto2。