Go Concurrency Patterns: The Production Engineer's Guide

Frequently Asked Questions

01.What is the difference between concurrency and parallelism in Go?

Concurrency is the composition of independently executing processes that can make progress in overlapping time periods; parallelism is the simultaneous execution of multiple computations. Go's scheduler multiplexes goroutines onto OS threads, enabling both: concurrency by design, and parallelism when GOMAXPROCS allows multiple threads to run simultaneously.

02.When should I use a buffered channel versus an unbuffered channel?

Use unbuffered channels when you need strict synchronization: the sender blocks until the receiver is ready, guaranteeing handoff. Use buffered channels to decouple sender and receiver temporarily, allowing the sender to proceed without waiting for an immediate consumer, up to the buffer capacity. Buffered channels work well in producer-consumer pipelines where burst traffic is expected.

03.How does context cancellation propagate across goroutines in Go?

The context package creates a tree of control. When a parent context is cancelled via cancel() or when its deadline expires, all child contexts derived from it receive the cancellation signal through their Done() channel. Each goroutine should select on ctx.Done() alongside its work channel so it can exit cleanly when cancellation propagates, preventing goroutine leaks and wasted compute.

04.What is the worker pool pattern and when should I use it?

The worker pool pattern maintains a bounded, fixed set of goroutines that pull work from a shared jobs channel. Use it when system resources such as memory, CPU, or external API rate limits constrain how many parallel operations can run safely. It prevents goroutine proliferation under load, which is critical for services handling unbounded input streams like REST handlers or queue consumers.

05.How do I prevent race conditions when multiple goroutines share state in Go?

The preferred approach is to share state only through channels, following Go's philosophy of communicating by sharing rather than sharing memory. When shared mutable state is unavoidable, use sync.Mutex for exclusive access or sync.RWMutex when reads dominate. Run go test -race during development to detect data races automatically. For simple counters and flags, sync/atomic offers lock-free operations with lower overhead than a mutex.