Add support for basic auth in maven schema registry plugin

[rhysmccaig]

I can't figure out how to get this repo to build locally, but this is my best guess at a patch that will support basic auth in the maven schema registry plugin. Would be great to get thoughts from anyone with better knowledge of the repo.

Edit: Got this building and tested. Its ready to merge if a committer can take a look. See comment below.

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[rhysmccaig]

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[rhysmccaig]

Successfully tested the following configurations after making this change:

• No basic auth supplied

<schemaRegistryUrls>
  <param>https://schema.registry/</param>
</schemaRegistryUrls>

• Basic auth details supplied via URL:

<schemaRegistryUrls>
  <param>https://username:password@schema.registry/</param>
</schemaRegistryUrls>
<basicAuthCredentialsSource>URL</basicAuthCredentialsSource>

• Basic auth details supplied via userInfoConfig parameter:

<schemaRegistryUrls>
  <param>https://schema.registry/</param>
</schemaRegistryUrls>
<basicAuthCredentialsSource>USER_INFO</basicAuthCredentialsSource>
<userInfoConfig>username:password<userInfoConfig>

[mageshn]

@rhysmccaig thanks a lot for getting to this. This will be super useful. Since the plugin is likely to be used from CI/CD and the credentials would also most likely be injected via CI tools, I would think that we don't have to expose the concept of basicAuthCredentialsSource. The plugin can just have properties for username and password and just user USER_INFO under the hood. It will make the configuration a lot simpler and straightforward. Thoughts?

[rhysmccaig]

@mageshn I had considered that, but also wondered if perhaps it makes sense to keep the URL option in case there are multiple schema registries to push the schemas to/validate against?

I'm happy with either approach. Let me know what you think and I can push the changes if required.

[mageshn]

@rhysmccaig you can only configure a plugin to go against a single SR cluster. So, I think it probably makes sense to simplify the configuration for this.

[rhysmccaig]

@mageshn ahh, fair enough. no worries - ill make the changes and push shortly

[rhysmccaig]

@mageshn should be good to go 👍

[mageshn]

LGTM. Thanks, @rhysmccaig for this contribution.