如何视频记录在docker内部无头运行的硒测试?

我正在使用无头firefox在docker内部运行python-selenium测试.

I am running python-selenium tests inside a docker using a headless firefox.

在这些测试过程中，我可以使用selenium方法来制作屏幕快照，但是我可以在整个测试过程中使用某些东西来视频"记录虚拟显示(一些测试脚本具有多种测试方法，并且启动了许多网络驱动程序，停止).

During these tests I am able to make screenshots with the selenium method for screenshots - but can I use something to 'video' record the virtual display during the whole test (several test scripts with several test methods, with many webdrivers started and stopped).

那么我该如何录制完整的测试会话呢?

So how can I video-record a complete test session?

附录:我找到了一个准确描述我需要的网页:

Addendum: I have found a webpage that describes exactly what I need: here. Unfortunately I get an error when I try to do the recording. Here are the commands I am doing:

xvfb-run --listen-tcp --server-num 44 --auth-file /tmp/xvfb.auth -s "-ac -screen 0 1920x1080x24" python seltest.py &
ffmpeg -f x11grab -video_size 1920x1080 -i 127.0.0.1:44 -codec:v libx264 -r 12 /tmp/behat_1.mp4

，错误是(对于第二个命令):

and the error is (for the second command):

[x11grab @ 0x1d289c0] Cannot open display 127.0.0.1:44, error 1.
127.0.0.1:44: Input/output error