implement gardenctl diag like what we have in gardener-robot ./diag shoot_url

[neo-liang-sap]

in gardener-robot we have ./diag shoot_url and shoot information is displayed, we would like to implement sth like this in gardenctl

[neo-liang-sap]

investigate whether it's easier to use gardener-robot docker image

[neo-liang-sap]

Hi @dansible ,
i checked whether it's more easy to use gardener-robot image to implement the diag command.

if i understand correctly, the image url is eu.gcr.io/sap-se-gcp-scp-k8s/gardener/robot:latest

i tried run this image but found several problems:

1. python2 needs to be uninstalled otherwise error looks like these
   
   i googled information related to this error but indicates i need to uninstall python2 https://superuser.com/questions/1537784/how-to-fix-errorrootcode-for-hash-md5-was-not-found-when-using-autojump-on

2. after uninstall python2 i still met problem i don't have permission with eu.gcr.io/sap-se-gcp-scp-k8s/
   

3. even we have the permission, say user run gardenctl diag to enter docker runtime of robot image, and then type ./diag shoot_url and then exit the docker runtime, it requires more effort compared with 1) gardenctl target shoot 2) gardenctl diag and then get all information from a shoot....

So personally i would prefer to use native go k8s client to pull information from shoot/seed, it's easy / no dependency / quick ...what do you think?

[neo-liang-sap]

will follow up to make the output looks like a table