Improvement: Improve vague/unhelpful error message when container name is not recognized

[ORESoftware]

I have this question on SO:
https://stackoverflow.com/questions/56203979/docker-run-invalid-reference-format?noredirect=1

I am getting this error:

docker: invalid reference format.
See 'docker run --help'.

I have this:

docker run --rm   \
    "$ecr_endpoint/notifier-cli:latest"                \
    --build-exit-code "$exit_code"                     \
    --event 'build-end'

the exit status of the docker run command is 125, if that helps. I have no idea what's going on here...an identical command is running fine earlier in the script.

so if the $ecr_endpoint variable was empty, then the docker run program likely saw this:

docker run --rm /notifier-cli:latest  ...

so maybe the error message could be improved somehow? an improved error message would help people - docker run should know that it's an image that doesn't exist, since nothing is expected after the --rm arg...right.