Go Concurrency for Web Applications

Quick Reference

Core Rules

1. Goroutines are cheap but not free — each goroutine consumes ~2-8 KB of stack. Unbounded spawning under load leads to OOM.
2. Always have a shutdown path — every goroutine you start must have a way to exit. Use context.Context, channel closing, or sync.WaitGroup.
3. Prefer channels for communication — use channels to coordinate work between goroutines and signal completion.
4. Use mutexes for state protection — when goroutines share mutable state, protect it with sync.Mutex, sync.RWMutex, or sync/atomic.
5. Never spawn raw goroutines in HTTP handlers — use worker pools, errgroup, or other bounded concurrency primitives.

Gates (check before merge or review)