[improve][cli]Support for pulsar-shell persistent modes

[sandeep-mst]

Fixes 21194 of apache/pulsar

Motivation

Pulsar shell doesn't support persistent mode for admin, client, config. If we need to run a lot of admin commands for example, we would need to prefix admin each time. This will provide an alternative approach.

Modifications

Modified so that admin, client, config commands individually will launch their own mode and prompt message also gets updated. exit or quit command will exit from the mode to the default mode.
In the admin mode, we can run command topics instead of admin topics.

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• The default values of configurations
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• The admin CLI options
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Matching PR in forked repository

PR in forked repository:
cognitree#6

[lhotari]

Good work @sandeep-mst . A few minor review comments.

[nicoloboschi]

I like this idea.

1. I think we should register the new commands like other commands in registerProviders(..) so automatic autocompletion will work for these modes too.

2. I don't understand the title, what do you mean by persistent modes ? I think we need a better name for this feature.

3. We should add docs, at least in the help (might be mitigated by 1.)

[lhotari]

I like this idea.

1. I think we should register the new commands like other commands in registerProviders(..) so automatic autocompletion will work for these modes too.
2. I don't understand the title, what do you mean by persistent modes ? I think we need a better name for this feature.
3. We should add docs, at least in the help (might be mitigated by 1.)

@sandeep-mst Have you considered addressing @nicoloboschi's review feedback?
For number 2 point, calling it a "subcontext" would be perhaps better unless that concept carries already a different meaning.

For example, windows netsh has the concept of contexts and subcontexts (top level is "context", which could have "subcontexts").

[sandeep-mst]

I like this idea.

1. I think we should register the new commands like other commands in registerProviders(..) so automatic autocompletion will work for these modes too.
2. I don't understand the title, what do you mean by persistent modes ? I think we need a better name for this feature.
3. We should add docs, at least in the help (might be mitigated by 1.)

@sandeep-mst Have you considered addressing @nicoloboschi's review feedback? For number 2 point, calling it a "subcontext" would be perhaps better unless that concept carries already a different meaning.

For example, windows netsh has the concept of contexts and subcontexts (top level is "context", which could have "subcontexts").

Hi @lhotari,

1. I have addressed the @nicoloboschi review feedback for supporting auto-completion for shell modes for admin and client. I removed config from the provided shell modes.

I tried to implement config shell mode even though it was not requested in the issue. I was facing lot of issues with it because config is stateful and implementation might require major changes to support auto-completion.

2. On the PR naming, context is already being used by window-functions-context of pulsar. We could still use it. Please, let me know your thoughts.
3. I will update the PR description after confirmation.