[ENH] Adds memberlist manager

[HammadB]

Description of changes

Summarize the changes made by this PR.

• Improvements & Bug fixes
  • Adds a memberlist manager to coordinator that listens to pod updates and reconciles them against a CR
• New functionality
  • N/A

Test plan

How are these changes tested?
New unit tests were added for this case for each module

• Tests pass locally with pytest for python, yarn test for js

Documentation Changes

None

[github-actions]

Reviewer Checklist

Please leverage this checklist to ensure your code review is thorough before approving

Testing, Bugs, Errors, Logs, Documentation

• Can you think of any use case in which the code does not behave as intended? Have they been tested?
• Can you think of any inputs or external events that could break the code? Is user input validated and safe? Have they been tested?
• If appropriate, are there adequate property based tests?
• If appropriate, are there adequate unit tests?
• Should any logging, debugging, tracing information be added or removed?
• Are error messages user-friendly?
• Have all documentation changes needed been made?
• Have all non-obvious changes been commented?

System Compatibility

• Are there any potential impacts on other parts of the system or backward compatibility?
• Does this change intersect with any items on our roadmap, and if so, is there a plan for fitting them together?

Quality

• Is this code of a unexpectedly high quality (Readbility, Modularity, Intuitiveness)

[HammadB]

Current dependencies on/for this PR:

• main
  • PR [ENH] Adds memberlist manager #1354 👈
    • PR [ENH] Update SubmitEmbeddingRecord to take collection_id. Update EmbeddingRecord to take collection_id #1359
      • PR [ENH] Add rendezvous hashing to go and python. Add Assignment policy to go so it can be used in future commits #1360
        • PR [ENH] Worker Topic Assignment #1376
          • PR [ENH] Proxy assignment #1378

This stack of pull requests is managed by Graphite.

[tazarov]

No major comments. Am I correct in my understanding that this is just an initial scaffolding for the controller, which will later take care of managing workers?

[HammadB]

TODO: investigate how to use context properly (pass into struct?)

[HammadB]

https://go.dev/blog/context-and-structs#:~:text=Contexts%20should%20not%20be%20stored,store%20it%20in%20another%20type.

[Ishiihara]

LGTM pending addressing review comments.

We need to followup on:

• Batch event processing to smooth start up and transient failures.
• Evaluate whether we need to customized CRD clients. We may need more CRDs to handle topic reconfiguration, ddl and TSOs.