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Add close method for static discovery to fix health check thread still running after reconfiguration

FIX #680 (link existing issues this PR will resolve)

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Summary of Changes

Hello @zerofishnoodles, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a critical bug where the static discovery health check thread would continue to run indefinitely even after reconfiguration, leading to resource leaks. The changes introduce a robust mechanism to properly terminate this background thread and its associated asynchronous event loop, ensuring that resources are released cleanly and preventing unintended background processes.

Highlights

  • Resource Management: Introduced a _running flag within the ServiceDiscovery class to control the execution of the health check loop, enabling graceful termination.
  • Asynchronous Operations: Replaced time.sleep with asyncio.sleep in the check_model_health method to ensure non-blocking asynchronous delays, improving concurrency.
  • Graceful Shutdown: Implemented a new close method in the ServiceDiscovery class responsible for setting the _running flag to False, stopping the associated event loop, and joining the health check thread, thereby ensuring proper resource cleanup upon reconfiguration or shutdown.
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Code Review

This pull request addresses a bug where the health check thread in StaticServiceDiscovery was not being terminated upon reconfiguration, leading to resource leaks. The changes introduce a close method to StaticServiceDiscovery to manage the lifecycle of the health check thread. The use of asyncio.sleep instead of time.sleep is a correct and important fix for the async health check function. My review focuses on making the new close method more robust to ensure a clean shutdown of the asyncio resources.

Signed-off-by: Rui Zhang <[email protected]>
@zerofishnoodles zerofishnoodles force-pushed the bugfix/static-discovery-close branch from 5d95def to 5e477a2 Compare September 10, 2025 18:56
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LGTM

@YuhanLiu11 YuhanLiu11 merged commit 5aa144d into vllm-project:main Sep 16, 2025
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Successfully merging this pull request may close these issues.

bug: Router keeps doing health checks based on old dynamic_config after change
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