feat: add kubectl auto-completion

[AObuchow]

Resolves the last part of eclipse-che/che#21735 by adding bash autocompletion for kubectl.

To test, use the following image quay.io/aobuchow/universal-developer-image:kubectl-completion, i.e.:

docker run -ti --rm \
       quay.io/aobuchow/universal-developer-image:kubectl-completion \
       bash

Then, with a shell inside the container, type in kubectl - and hit TAB twice to see autocomplete results.
The output should resemble the following:

projects $ kubectl -
--add-dir-header            --client-key                --log-dir=                  --namespace=                --skip-log-headers          --v=
--alsologtostderr           --client-key=               --log-file                  --password                  --stderrthreshold           --vmodule
--as                        --cluster                   --log-file-max-size         --password=                 --stderrthreshold=          --vmodule=
--as-group                  --cluster=                  --log-file-max-size=        --profile                   --tls-server-name           --warnings-as-errors
--as-group=                 --context                   --log-file=                 --profile-output            --tls-server-name=          -n
--as=                       --context=                  --log-flush-frequency       --profile-output=           --token                     -s
--cache-dir                 --insecure-skip-tls-verify  --log-flush-frequency=      --profile=                  --token=                    -v
--cache-dir=                --kubeconfig                --loglevel                  --request-timeout           --user                      
--certificate-authority     --kubeconfig=               --loglevel=                 --request-timeout=          --user=                     
--certificate-authority=    --log-backtrace-at          --logtostderr               --server                    --username                  
--client-certificate        --log-backtrace-at=         --match-server-version      --server=                   --username=                 
--client-certificate=       --log-dir                   --namespace                 --skip-headers              --v 

[l0rd]

A part for a minor suggestion it worked for me

[l0rd]

I would move everything related to kubectl in the dedicated heredoc

Suggested change

	echo '[ -f ~/.kubectl_aliases ] && source ~/.kubectl_aliases' >> /home/user/.bashrc
	EOF
	# kubectl completion
	RUN kubectl completion bash > /usr/share/bash-completion/completions/kubectl \
	&& echo "source /usr/share/bash-completion/completions/kubectl" >> /home/user/.bashrc
	kubectl completion bash > /usr/share/bash-completion/completions/kubectl
	echo '[ -f ~/.kubectl_aliases ] && source ~/.kubectl_aliases' >> /home/user/.bashrc
	echo "source /usr/share/bash-completion/completions/kubectl" >> /home/user/.bashrc
	EOF

[amisevsk]

Looking at the .bashrc in the container, I see a warning that sdkman only works if the relevant lines are at the end of .bashrc, but we've injected a bunch of source lines after that block -- is the sdkman warning still true? cc: @l0rd

An easier way to do completions (but one that would require reworking all completions in the dockerfile) would be something like what WTO does:

• In .bashrc: source /etc/profile.d/bash_completion.sh [1]
• In dockerfile: put completions in $COMPDIR: [2]

[amisevsk]

Further detail on the sdkman concern: this is the current .bashrc in the image:

#THIS MUST BE AT THE END OF THE FILE FOR SDKMAN TO WORK!!!
export SDKMAN_DIR="$HOME/.sdkman"
[[ -s "$HOME/.sdkman/bin/sdkman-init.sh" ]] && source "$HOME/.sdkman/bin/sdkman-init.sh"

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"  # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"  # This loads nvm bash_completion
source /usr/share/bash-completion/completions/git
source /usr/share/bash-completion/completions/oc
[ -f ~/.kubectl_aliases ] && source ~/.kubectl_aliases
export PATH="${KREW_ROOT:-$HOME/.krew}/bin:$PATH"

[AObuchow]

Looking at the .bashrc in the container, I see a warning that sdkman only works if the relevant lines are at the end of .bashrc, but we've injected a bunch of source lines after that block -- is the sdkman warning still true? cc: @l0rd

An easier way to do completions (but one that would require reworking all completions in the dockerfile) would be something like what WTO does:

Thanks for pointing this out & suggesting an alternative approach @amisevsk. I'm going to take a bit longer to work on this PR to try and see if I can rework all the completions in the dockerfile.

[l0rd]

@amisevsk I don't know what's the side effect of the SDKMAN being initialized earlier in the .bashrc file, but I agree that we should fix it and your solution is elegant so let's do that.

@AObuchow if you want to do that work in a separate PR is ok too and we can merge this one in the meantime.

[amisevsk]

+1 to merge with @l0rd's suggestion from review, and then optionally rework completions as a separate PR

[openshift-ci]

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This pull-request has been approved by: amisevsk, AObuchow, l0rd

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[AObuchow]

I think this PR can be closed as it's made redundant by https://github.com/devfile/developer-images/pull/107/files#diff-9f21bef4669d474b6ddef409447be53ae91c94cb50b6df9345149a0e89fb5391R229 @l0rd

[l0rd]

I think this PR can be closed as it's made redundant by #107 (files) @l0rd

Sorry, that was a mistake. I wanted to test your PR and I rebased mine on top of yours and then I forget about it and pushed your changes too 🤷 . So yes I think we can close this one.

[AObuchow]

@l0rd no worries 😎 sounds good, closing.