Fix gRPC stream observer leak on ProcessBundleHandler shutdown#39390
Fix gRPC stream observer leak on ProcessBundleHandler shutdown#39390Abacn wants to merge 1 commit into
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* tears down active gRPC multiplexers on ProcessBundleHandler shutdown
| /** Shutdown the bundles, running the tearDown() functions. */ | ||
| public void shutdown() throws Exception { | ||
| bundleProcessorCache.shutdown(); | ||
| beamFnDataClient.close(); |
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BeamFnDataGrpcClient is created in FnHarness.main:
and ownership passed to ProcessBundleHandler:
Therefore we should close it here.
When FnHarness.main is invoked multiple times (instead of as a standalone worker like on Dataflow runner), previously unclosed BeamFnDataGrpcClient leak gRPC streams
Summary of ChangesHello, 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 resource leak occurring during the shutdown of the ProcessBundleHandler. By introducing a formal closing mechanism for the gRPC data client and its associated multiplexers, the changes ensure that network resources are correctly released, preventing potential memory or connection leaks in the Beam Fn harness. Highlights
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Code Review
This pull request updates BeamFnDataClient to extend Closeable and implements the close() method in BeamFnDataGrpcClient to clean up cached multiplexers. It also integrates this cleanup into ProcessBundleHandler.shutdown(). The review feedback suggests wrapping the shutdown operations in a try-finally block to prevent resource leaks if an exception occurs, and logging exceptions caught when closing multiplexers instead of swallowing them silently.
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| public void shutdown() throws Exception { | ||
| bundleProcessorCache.shutdown(); | ||
| beamFnDataClient.close(); | ||
| } |
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If bundleProcessorCache.shutdown() throws an exception, beamFnDataClient.close() will not be called, potentially leaking resources. Wrapping the shutdown calls in a try-finally block ensures that beamFnDataClient.close() is always executed.
public void shutdown() throws Exception {
try {
bundleProcessorCache.shutdown();
} finally {
beamFnDataClient.close();
}
}| for (BeamFnDataGrpcMultiplexer client : multiplexerCache.values()) { | ||
| try { | ||
| client.close(); | ||
| } catch (Exception e) { | ||
| // proceed to close other clients | ||
| } | ||
| } |
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Swallowing exceptions silently during shutdown makes debugging difficult when multiplexers fail to close properly. It is recommended to log the exception at a warning level.
| for (BeamFnDataGrpcMultiplexer client : multiplexerCache.values()) { | |
| try { | |
| client.close(); | |
| } catch (Exception e) { | |
| // proceed to close other clients | |
| } | |
| } | |
| for (BeamFnDataGrpcMultiplexer client : multiplexerCache.values()) { | |
| try { | |
| client.close(); | |
| } catch (Exception e) { | |
| LOG.warn("Failed to close multiplexer", e); | |
| } | |
| } |
|
Assigning reviewers: R: @kennknowles for label java. Note: If you would like to opt out of this review, comment Available commands:
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