[TT-1180] use RWMutex to protect LogStream's consumer map

[Tofel]

Tried and tested here

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Below is a summarization created by an LLM (gpt-4-0125-preview). Be mindful of hallucinations and verify accuracy.

Why

The changes enhance thread safety and error handling in the log streaming system. By introducing mutex locking, the code ensures that consumer access is synchronized, preventing data races. The addition of a no-op function for post-disconnect scenarios and the restructuring of shutdown procedures allow for more flexible and error-resilient shutdown logic. These modifications aim to improve the reliability and maintainability of the log streaming system.

What

• logstream/logprocessor.go
  • Added RLock() and RUnlock() around consumer access to ensure thread safety during log processing.
• logstream/logstream.go
  • Introduced a consumerMutex of type sync.RWMutex to manage concurrent access to the consumer map.
  • Implemented mutex locking (Lock() and Unlock()) around modifications to the consumers map to prevent data races.
  • Added RLock() and RUnlock() around read operations on consumers to ensure thread safety.
  • Removed the direct error wrapping logic in Shutdown and replaced it with a more structured approach using shutdownWithFunction, allowing for additional operations post-disconnection but before Loki shutdown.
  • Added noOpPostDisconnectFn, a no-operation function used as a default argument for shutdownWithFunction for cases where no additional operations are needed post-disconnection.
  • Modified FlushAndShutdown to use shutdownWithFunction, incorporating log flushing as the post-disconnect operation.
  • Ensured read locks are applied during operations that read from the consumers map without modifying it, enhancing thread safety without unnecessary write locks.

[cl-sonarqube-production]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarQube