Added support of direct write mode

[alex268]

No description provided.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 94.47514% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 71.07%. Comparing base (8556216) to head (bdb9c8c).

Files with missing lines	Patch %	Lines
.../tech/ydb/topic/write/impl/WriteStreamFactory.java	95.57%	2 Missing and 3 partials ⚠️
...main/java/tech/ydb/topic/impl/TopicStreamFail.java	72.72%	3 Missing ⚠️
topic/src/main/java/tech/ydb/topic/TopicRpc.java	0.00%	1 Missing ⚠️
...rc/main/java/tech/ydb/topic/impl/GrpcTopicRpc.java	87.50%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #641      +/-   ##
============================================
+ Coverage     70.87%   71.07%   +0.20%     
- Complexity     3314     3341      +27     
============================================
  Files           374      377       +3     
  Lines         15699    15810     +111     
  Branches       1650     1662      +12     
============================================
+ Hits          11126    11237     +111     
+ Misses         3931     3927       -4     
- Partials        642      646       +4     

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[Copilot]

Pull request overview

Adds “direct write” support for topic writers by allowing write sessions to target a preferred node (derived from partition location), and refactors the internal stream abstraction to support both real and pre-failed streams.

Changes:

• Introduce WriteStreamFactory to construct regular or direct-write streams (by partitionId or producerId).
• Refactor TopicStream into an interface with concrete implementations TopicStreamBase and TopicStreamFail.
• Add/adjust tests validating direct write behavior and the new stream base class usage.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
topic/src/main/java/tech/ydb/topic/write/impl/WriteStreamFactory.java	New factory implementing direct-write selection + partition/node probing logic.
topic/src/main/java/tech/ydb/topic/write/impl/WriteStream.java	Switch to TopicStreamBase and add Fail stream implementation.
topic/src/main/java/tech/ydb/topic/write/impl/WriteSession.java	Wire WriteStreamFactory into retryable write session creation.
topic/src/main/java/tech/ydb/topic/settings/WriterSettings.java	Add direct write flag and builder setter.
topic/src/main/java/tech/ydb/topic/impl/TopicStream.java	Convert from abstract class to interface.
topic/src/main/java/tech/ydb/topic/impl/TopicStreamBase.java	New concrete base implementation wrapping grpc stream behavior.
topic/src/main/java/tech/ydb/topic/impl/TopicStreamFail.java	New stream implementation that fails immediately with a fixed status.
topic/src/main/java/tech/ydb/topic/impl/GrpcTopicRpc.java	Add writeSession(id, directWriteNodeId) with direct-mode request settings.
topic/src/main/java/tech/ydb/topic/TopicRpc.java	Extend API with default overload for direct-write node targeting + proto type import cleanup.
topic/src/test/java/tech/ydb/topic/write/impl/WriteStreamFactoryTest.java	New tests for direct write factory scenarios and failures.
topic/src/test/java/tech/ydb/topic/impl/TopicStreamTest.java	Update test to use TopicStreamBase.
topic/src/test/java/tech/ydb/topic/impl/TopicRetryableStreamTest.java	Update mocks/types to reflect new TopicStream interface/base.

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[robot-vibe-db]

Overall: the refactoring from TopicStream (abstract class) to TopicStream (interface) + TopicStreamBase + TopicStreamFail is well-structured. The TopicStreamFail pattern integrates cleanly with the retry mechanism in TopicRetryableStream — when direct write setup fails, the failure status flows through the existing retry logic, so transient errors (e.g. UNAVAILABLE from describeTopic) get retried while non-retryable errors (e.g. BAD_REQUEST for missing partition) stop the writer. The test coverage for WriteStreamFactory is thorough and covers the important success and failure paths for both partition-id-based and producer-id-based direct write modes.

See inline comments for potential issues found during review.

[robot-vibe-db]

Overall: the refactoring from TopicStream (abstract class) to TopicStream (interface) + TopicStreamBase + TopicStreamFail is well-structured. The TopicStreamFail pattern integrates cleanly with the retry mechanism in TopicRetryableStream — when direct write setup fails, the failure status flows through the existing retry logic, so transient errors (e.g. UNAVAILABLE from describeTopic) get retried while non-retryable errors (e.g. BAD_REQUEST for missing partition) stop the writer. The test coverage for WriteStreamFactory is thorough and covers the important success and failure paths for both partition-id-based and producer-id-based direct write modes.

See inline comments for potential issues found during review.

[robot-vibe-db]

I reviewed the changes in context of the surrounding codebase. The PR restructures the write-side stream infrastructure — splitting TopicStream into an interface + base implementation + fail implementation, extracting StreamFactory from WriteSession into a standalone WriteStreamFactory, and adding direct write mode support. Overall the code flow is correct and test coverage is good. I found no critical issues in the changes.

A few non-critical observations below in inline comments.

[robot-vibe-db]

No critical issues found in the code changes. The refactoring of the write-side stream infrastructure is well-structured and the direct write mode implementation is correct. A few non-critical observations below.