Add Throwable safety net to CloudWatch Logs sink Uploader#6888
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dlvenable merged 1 commit intoJun 3, 2026
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When an unchecked Throwable escaped Uploader.upload(), the executor worker thread terminated silently. The batch's events were never acknowledged, never DLQ'd, and never reflected in any metric — a fatal classpath or runtime issue produced no operator-visible signal beyond a single stderr line from ThreadPoolExecutor. This change makes such failures observable and recoverable: the unhandled-error path now emits a dedicated metric and structured log, accounts the lost events in the existing failure counter, and releases event handles so the source can make forward progress instead of waiting indefinitely for an ack. Closing the safety gap also required fixing a latent correctness bug that a naive catch-all would have compounded. Success and failure metrics were incremented before the post-loop cleanup ran, so a Throwable escaping after that point would have produced succeeded + failed > total — breaking any percentage-based dashboard or "no events failed" alarm. Without addressing this, the safety net would have traded silent loss for inconsistent metrics. Signed-off-by: Nikhil Bagmar <nikhilbagmar73@gmail.com>
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…-project#6888) When an unchecked Throwable escaped Uploader.upload(), the executor worker thread terminated silently. The batch's events were never acknowledged, never DLQ'd, and never reflected in any metric — a fatal classpath or runtime issue produced no operator-visible signal beyond a single stderr line from ThreadPoolExecutor. This change makes such failures observable and recoverable: the unhandled-error path now emits a dedicated metric and structured log, accounts the lost events in the existing failure counter, and releases event handles so the source can make forward progress instead of waiting indefinitely for an ack. Closing the safety gap also required fixing a latent correctness bug that a naive catch-all would have compounded. Success and failure metrics were incremented before the post-loop cleanup ran, so a Throwable escaping after that point would have produced succeeded + failed > total — breaking any percentage-based dashboard or "no events failed" alarm. Without addressing this, the safety net would have traded silent loss for inconsistent metrics. Signed-off-by: Nikhil Bagmar <nikhilbagmar73@gmail.com>
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When an unchecked Throwable escaped Uploader.upload(), the executor worker thread terminated silently. The batch's events were never acknowledged, never DLQ'd, and never reflected in any metric — a fatal classpath or runtime issue produced no operator-visible signal beyond a single stderr line from ThreadPoolExecutor. This change makes such failures observable and recoverable: the unhandled-error path now emits a dedicated metric and structured log, accounts the lost events in the existing failure counter, and releases event handles so the source can make forward progress instead of waiting indefinitely for an ack.
Closing the safety gap also required fixing a latent correctness bug that a naive catch-all would have compounded. Success and failure metrics were incremented before the post-loop cleanup ran, so a Throwable escaping after that point would have produced succeeded + failed > total — breaking any percentage-based dashboard or "no events failed" alarm. Without addressing this, the safety net would have traded silent loss for inconsistent metrics.
Description
[Describe what this change achieves]
Issues Resolved
Resolves #6887
Check List
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