Docker return codes from background commands
I’m not getting the return code I expect, when executing a script inside a Docker container with a background task run in it.
This example docker file highlights the problem:
FROM ubuntu:latest MAINTAINER Jakob H. Thomsen (firstname.lastname@example.org) RUN echo "#!/bin/bash\nset -e\n\nls / &\nexit 1" > /start_script.sh RUN chmod +x /start_script.sh
It creates the following file
/start_script.sh inside the container:
#!/bin/bash set -e ls / & exit 1
docker build -t jakob/test . and
docker run jakob/test cat /start_script.sh you would expect the return code to be 1, because of the
exit 1. It is not, it is 0 and it is somehow because of the
ls / & (if you remove that command you get the expected return code of 1).
So my question is why
ls / & overrides the return code of the
exit 1 command? I tried making
exit 1 to run in the background, but it doesn’t change the return code…
As I’m using the setup to run Ruby specs, I’m really dependent upon the return code of the last command, so is there something I can do to make Docker return the return code of the last command?
Thanks and I hope you can help, as it has taking me a loong time to pinpoint the exact issue of these ‘wrong’ return codes.
One Solution collect form web for “Docker return codes from background commands”
Turned out that the issue is fixed in the newest version of Docker: https://github.com/dotcloud/docker/issues/3775