prevent concurrent data races

Always analyze shared data access patterns to prevent race conditions in concurrent code. Use appropriate synchronization mechanisms based on access patterns and data ownership.

Key practices:

1. Use RLock for read-heavy scenarios: When data is read frequently but written rarely, use sync.RWMutex with RLock() to allow concurrent reads while still protecting against concurrent writes.

2. Copy data when sharing between goroutines: When the same data structure will be accessed by multiple goroutines that might modify it, create copies to prevent races.

3. Avoid unmanaged goroutines: Don’t spawn goroutines without proper lifecycle management. Use sync.WaitGroup or context cancellation to ensure cleanup.

4. Understand library thread safety: Before adding locks around external library calls, verify if the library is already thread-safe. Adding unnecessary locks can cause performance issues.

Example of proper data copying to prevent races:

func relabelAlerts(alerts []*Alert) []*Alert {
    var relabeledAlerts []*Alert
    for _, s := range alerts {
        // Copy the alert to avoid race condition when multiple 
        // goroutines modify the same alert pointers
        a := s.Copy()
        // ... relabel operations on copy
        relabeledAlerts = append(relabeledAlerts, a)
    }
    return relabeledAlerts
}

Always run tests with -race flag to detect potential race conditions during development.