use env variable CONTAINER to choose the docker container

[HoxhaEndri]

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)
  fixes Docker registry variable for EMBA installation #638

• What is the current behavior? (You can also link to an open issue here)
  downloads the emba docker

• What is the new behavior (if this is a feature change)? If possible add a screenshot.
  you can set the env variable CONTAINER to use your container

• Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?)

• Other information:

[HoxhaEndri]

For this to work, first the CONTAINER variable must be exported either in the root environment or executing the installer script mantaining the environment variables of the user: sudo -E ./installer.sh -d.

[m-1-k-3]

ping @secsonthebeach. Would you like to check this PR and give us your feedback?

[m-1-k-3]

@HoxhaEndri please update the wiki information to document the new installation possibilities

[secsonthebeach]

ping @secsonthebeach. Would you like to check this PR and give us your feedback?

Hello, sorry for the delay. I am looking into this. Thank you for picking it up!
Not very smart on Git, is this commit merged to master, or is there some other way to verify a PR?
I pulled master at f2c02ed and ran the installer with the CONTAINER env var set.

The installer was failing at installer/I05... with an error reaching the registry. It appears to still be trying docker.io, rather than our internal proxy/cache

Okay, I've now cloned @HoxhaEndri master and it failed at the same place. It was line 29 of installer/I05... which makes sense because the docker manifest inspect embeddedanalyzer/emba:latest line would need to reference the CONTAINER variable as well.

I've tested that command manually using the same CONTAINER env var and it works (example: private-registry.harbor.domain/dockerhub.reference/embeddedanalyzer/emba)

Could you move the if statement on line 51 of installer/I05... to somewhere else, so that the container URL is set for all other docker calls? Or possibly add it to the arg parser for the overall install script?

With the env var set, changing the docker command on line 29 to docker manifest inspect ${CONTAINER} worked to get past the previous failure.... still running...

[HoxhaEndri]

@m-1-k-3, on thursday I am going to update the wiki.