Just a collection of my personal notes about Docker usage.
PROBLEM: Sometime u would like to override the entrypoint of a Docker container.
For example if u try to run robod0ck by just calling
docker run robod0ck/robod0ck u will most likely get the error [ ERROR ] Expected at least 1 argument, got 0.
That's because the entrypoint of the container is the Robot Framework command robot which is assuming at least one arg
e.g. a .robot file or a folder with test cases or some command line option like --help, --version etc.
So no matter what u do, the container will run the robot command. But what if u want to start an interactive shell session
in that container or check the version of RF or Pip installed inside the container?
Like for example docker run robod0ck/robod0ck bash.
SOLUTION: You have to override the entrypoint!
NOTE: Be aware that arguments/'command line options' have to be put after the container id/image identifier
docker run -it --entrypoint "command-you-want-to-run" <container-id> <command arguments / cli-options>
# examples
# start interactive bash session
docker run -it --entrypoint "/bin/bash" <container-id>
# print the version of bash
# notice how cli-option '--version' comes after the container id
docker run -it --entrypoint "/bin/bash" <container-id> --version
# list installed python packages with pip
# notice how argument 'list' comes after the image name
docker run --entrypoint "pip" robod0ck/robod0ck list