fix(inputs.prometheus): Add thread safety and proper cleanup for shared informer factories#18377
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mstrandboge merged 3 commits intoinfluxdata:masterfrom Feb 23, 2026
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…ed informer factories The shared informer factory map is accessed concurrently by multiple plugin instances during Start/Stop, causing race conditions. The prior cleanup (delete from map) also leaked goroutines by not calling Shutdown() and could prematurely remove a factory still in use by another instance. Add a mutex to protect all access to the shared informer factory map, a reference counter to track active users per namespace, and an explicit Shutdown() call when the last user releases a factory.
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Summary
Follow-up to #18304 which added
delete(informerfactory, p.PodNamespace)inStop()to clean up shared informer factories. That fix addressed the resource leak but left three issues:Race condition: The
informerfactorymap is package-level shared state accessed concurrently by multiple plugin instances duringStart()/Stop()without synchronization, this is undefined behavior in Go and can panic at runtimeGoroutine leak: Deleting from the map doesn't stop the watcher goroutines spawned by
SharedInformerFactory.Start(), callingShutdown()is required to terminate themPremature deletion: If two instances share a factory (same namespace), the first to stop deletes it from under the second
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Related issues
related #18304