Setup initial namespaces with MetadataStore

[fantapsody]

Motivation

Refactor the initial namespaces setup command to use the new MetadataStore API.

Explain here the context, and why you're making that change. What is the problem you're trying to solve.

Modifications

• Refactored PulsarInitialNamespaceSetup command to use the new MetadataStore API.

Describe the modifications you've done.

Verifying this change

• Make sure that the change passes the CI checks.

This change is already covered by existing tests, such as ClusterMetadataSetupTest.

(or)

This change added tests and can be verified as follows:

• Added unit tests for the PulsarInitialNamespaceSetup command

Does this pull request potentially affect one of the following parts:

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): (no)
• The public API: (no)
• The schema: (no)
• The default values of configurations: (no)
• The wire protocol: (no)
• The rest endpoints: (no)
• The admin cli options: (no)
• Anything that affects deployment: (no)

Documentation

• Does this pull request introduce a new feature? (no)

[eolivelli]

LGTM

We may have a problem with the new test case as the new refactored method may call System.exit, breaking the execution of the JVM.

I would be better to be able to pass to the PulsarInitialNamespaceSetup.main() function a callback to be executed in case of failure and use that version for tests

PulsarInitialNamespaceSetup.main(arguments,  (exitCode) -> {
    fail the test
});

[fantapsody]

LGTM

We may have a problem with the new test case as the new refactored method may call System.exit, breaking the execution of the JVM.

I would be better to be able to pass to the PulsarInitialNamespaceSetup.main() function a callback to be executed in case of failure and use that version for tests

PulsarInitialNamespaceSetup.main(arguments,  (exitCode) -> {
    fail the test
});

@eolivelli Thanks for the idea! I modified the code in a similar way by moving the code from main to doMain and let doMain return a status code, please take another look.

[merlimat]

@eolivelli @fantapsody has already addressed the comments

[eolivelli]

LGTM