[FIXED] Docker build output scripts ran from dockerfile

Issue

I'm running a

docker build -t $NAME -f Dockerfile.test .

command.

In my Dockerfile.test I have at the end (I'm copying certain things to make everything work)

CMD["bin/bash", "-c", "bash /run-script.sh && bash /run-another-script.sh"]

When I look at my build stages in Jenkins, I can only see that everything passed ok, the

CMD /bin/bash -c bash /run-script.sh && bash /run-another-script.sh

was executed, and since I'm running a sonarqube scan in these scripts, I can see in my sonarqube that a scan happened (which is ok).

But since I'm running PHP unit tests in the scripts, I'm a bit suspicious that this part, because in the Jenkins this was done very quickly (on my local computer running unit testing with coverage report takes ~20min), failed, or didn't run as it should.

So I'd like to see the output of these scripts (run-script.sh and run-another-script.sh) to be sure that everything works as intended.

I've heard that docker won't show the output of the scripts that write/delete lines in the terminal, so this might be the reason (I'm guessing ofc).

Is there a way to show the output?

Solution

I think you are confusing RUN and CMD.

RUN-commands are executed during the build (docker build), CMD-commands are executed when you start the container (docker run).

To be certain I have written a small test:

1. Using CMD

   $ docker build -t cmdtest -<<EOF FROM centos:7

   RUN echo "echo script1" > script1.sh RUN echo "echo script2" > script2.sh

   CMD ["bin/bash", "-c", "bash /script1.sh && bash /script2.sh"] EOF

does not print anything, because not executed. However, prints at docker run:

$ docker run cmdtest
> script1
> script2

2. Using RUN

   $ docker build -t cmdtest -<<EOF FROM centos:7

   RUN echo "echo script1" > script1.sh RUN echo "echo script2" > script2.sh

   RUN ["bin/bash", "-c", "bash /script1.sh && bash /script2.sh"] EOF

   Sending build context to Docker daemon 2.048 kB ... Step 4/4 : RUN bin/bash -c bash /script1.sh && bash /script2.sh ---> Running in 7aab2725ed25

   script1 script2 ---> 8ca71d1c67e8

prints at build-time.

Answered By - Fabian Braun