In order to perform some JavaScript unit tests with karma inside a docker container (based on ubuntu 14.04) I'm starting firefox in the container using a karma-script-launcher with xvfb-run. The start script looks like this:
#!/bin/bash
set -o errexit
# nasty workaround as xvfb-run doesn't cleanup properly...
trap "pkill -f /usr/lib/firefox/firefox" EXIT
xvfb-run --auto-servernum --server-args='-screen 0, 1024x768x16' firefox $1
Starting the browser and executing the unit tests works very well. After executing the tests karma terminates the spawned browser instance - in my case the script that launched firefox over xvfb-run.
In the above script you can see that I registered a trap to kill the launched firefox on exit of my script. This works, but the script is not a very nice citizen as it terminates all instances of firefox that are currently running instead of just terminating the one instance that was launched by the script. I first tried to kill the xfvb-run process but killing this process has no effect on the sub-process launched by the xvfb-run script...
If I start firefox over xvfb-run manually there is a bunch of spawned processes:
root@1d7a5988e521:/data# xvfb-run --auto-servernum --server-args='-screen 0, 1024x768x16' firefox &
[1] 348
root@1d7a5988e521:/data# ps ax
PID TTY STAT TIME COMMAND
1 ? Ss 0:00 bash
348 ? S 0:00 /bin/sh /usr/bin/xvfb-run --auto-servernum --server-args=-screen 0, 1024x768x16 firefox
360 ? S 0:00 Xvfb :99 -screen 0, 1024x768x16 -nolisten tcp -auth /tmp/xvfb-run.bgMEuq/Xauthority
361 ? Sl 0:00 /usr/lib/firefox/firefox
378 ? S 0:00 dbus-launch --autolaunch bcf665e095759bae9fc1929b57455cad --binary-syntax --close-stderr
379 ? Ss 0:00 //bin/dbus-daemon --fork --print-pid 5 --print-address 7 --session
388 ? S 0:00 /usr/lib/x86_64-linux-gnu/gconf/gconfd-2
414 ? R+ 0:00 ps ax
root@1d7a5988e521:/data#
If I now kill the xvfb-run process (PID 348), only this process will be terminated, leaving the other processes running. If I kill the firefox process (PID 361) instead, the xvfb-run script correctly terminates and kills the other processes as well. But from my script I only know the PID of the xvfb-run process...
During my research I stumbled across this rather old bug report for xvfb-run which still seems to be valid in spite of the bug's status beeing fixed back in 2012.
Is there any polite way to terminate the xvfb-run process in order for the other processes to be cleaned up correctly?
Answer
I posted this question on unix.stackexchange.com some time ago as this is more related to Unix/Linux than to programming in general and did not attract much attention here:
Howto terminate xvfb-run properly @ Unix & Linux
However the only option to terminate the X-programs correclty seems to be the not use xvfb-run and to write your own script to start the processes with Xvfb.