A goroutine leak in thanos/internal/cortex/util/services /basic_service.go

[xuxiaofan1203]

When runningFn is called, the goroutine is blocked.

thanos/internal/cortex/util/services/basic_service.go

Lines 192 to 194 in da855a1

	if b.runningFn != nil {
	err = b.runningFn(b.serviceContext)
	}

The b.serviceCancel() can awaken the blocked goroutine. However, because the goroutine has blocked at runningFn. So the statement can't get executed, resulting in the gouroutine leak.

thanos/internal/cortex/util/services/basic_service.go

Line 207 in da855a1

b.serviceCancel()

How to fix the bug:
I provide a solution that involves calling runningFn in a new goroutine to ensure the execution of serviceCancel(), as follows.

go func() {
      err = b.runningFn(b.serviceContext) 
}()

[dosubot]

Hey @xuxiaofan1203, I'm here to help you with that goroutine leak issue. I'm a bot designed to assist you in solving bugs, answering questions, and becoming a contributor. Let's tackle this together!

Running runningFn in a separate goroutine, as suggested, can indeed help address the goroutine leak issue by allowing serviceCancel() to be executed independently. However, this approach can introduce potential side effects related to service lifecycle management and error handling.

1. Service Lifecycle Management: runningFn is expected to block until the service should transition to the Stopping state. Executing it in a separate goroutine may cause the service to prematurely enter the Stopping state, disrupting the expected lifecycle management ^[1].

2. Error Handling: If runningFn returns an error while running in a separate goroutine, it may not be properly captured by the service's error handling mechanism, leading to incorrect state transitions or unhandled errors ^[1].

3. Context Management: The context passed to runningFn is canceled when StopAsync() is called or when the service enters the Stopping state. Running runningFn in a separate goroutine may lead to improper handling of context cancellation, potentially causing resource leaks or incomplete cleanup operations ^[1].

To mitigate these issues, ensure that the service's state transitions and error handling mechanisms are adapted to accommodate the asynchronous execution of runningFn. This might involve additional synchronization mechanisms to ensure that the service lifecycle and error handling are correctly managed.

To continue talking to Dosu, mention @dosu.

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