feat: transparent leader hint reconnect on consume

[vieiralucas]

Summary

• When consume receives gRPC UNAVAILABLE with x-fila-leader-addr trailing metadata, the client transparently reconnects to the leader address and retries once
• Applies to both sync Client and async AsyncClient
• Connection parameters (TLS certs, API key) are stored and reused when creating the redirected channel
• Max 1 redirect per consume call to prevent infinite loops

Test plan

• Verify existing integration tests still pass (no behavior change for non-cluster setups)
• Test with a multi-node cluster where consumer connects to a follower node
• Verify UNAVAILABLE without leader hint metadata still raises RPCError
• Verify second UNAVAILABLE after redirect raises RPCError (no infinite loop)

🤖 Generated with Claude Code

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Summary by cubic

Automatically reconnects to the hinted leader and retry once when a consume call hits a follower. Works for both sync Client and AsyncClient, reuses TLS/mTLS credentials and API key, and closes the old channel before reconnecting.

• New Features

  • Detects gRPC UNAVAILABLE with x-fila-leader-addr and retries consume against the leader once.
  • Reuses stored TLS CA and optional client cert/key plus API key when creating the new channel.
  • If no leader hint is present, or the retry fails, the client raises the mapped RPCError.

• Bug Fixes

  • Closes the previous gRPC channel before reconnecting to avoid leaked connections.
  • Resolves mypy no-any-return issues by adding return types and channel factory helpers (no behavior change).

^{Written for commit 273746e. Summary will update on new commits.}

[cubic-dev-ai]

2 issues found across 2 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="fila/client.py">

<violation number="1" location="fila/client.py:235">
P2: Close the existing gRPC channel before replacing it during redirect to avoid leaking connections.</violation>
</file>

<file name="fila/async_client.py">

<violation number="1" location="fila/async_client.py:245">
P1: Old gRPC channel is leaked on reconnect. `self._channel` is overwritten without closing the previous channel first, leaving its file descriptors and background tasks open until GC (if ever).</violation>
</file>

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