Common Concurrency Pitfalls in Go and How to Avoid Them

Common Concurrency Pitfalls in Go and How to Avoid Them

Go's concurrency model, centered around goroutines and channels, is one of its most celebrated features. It allows developers to write highly concurrent programs with a relatively straightforward syntax. However, the ease of spawning thousands of goroutines can be deceptive. Without careful design, developers can easily fall into traps that cause elusive bugs, performance degradation, and system crashes. Understanding these common pitfalls is the first step toward writing robust, production-ready concurrent code.

1. Uncontrolled Goroutine Lifetimes and Leaks

A classic mistake is launching a goroutine without a clear plan for its termination. A goroutine that runs indefinitely, or one that is blocked waiting on a channel that never receives a value, constitutes a goroutine leak. Like memory leaks, these accumulate over time, consuming system resources and potentially leading to out-of-memory errors.

How to Avoid: Always have an exit strategy. Use context.Context for cancellation. For worker pools or fan-out patterns, employ a sync.WaitGroup to wait for completion. Ensure channels are properly closed by the producer to signal receivers that no more data is coming.

// Good: Using context for cancellation ctx, cancel := context.WithCancel(context.Background()) defer cancel() // Ensures cleanup on function exit go func(ctx context.Context) { for { select { case