Go Concurrency Distilled

A concise mini-book that distills practical concurrency patterns and pitfalls in Go, aimed as a quick refresher rather than a beginner's tutorial. It walks through core primitives - goroutines, channels, select, pipelines, timers and tickers, context cancellation, wait groups, mutexes, condition variables, semaphores, sync.Once, object pools and atomics - accompanied by interactive examples and a static PDF. It emphasizes that goroutines are lightweight and scheduled onto OS threads, that main exits terminate other goroutines, and that WaitGroup and the convenience WaitGroup.Go are standard synchronization tools. Common pipeline and channel patterns are shown, and timers expose their C channel for event scheduling.

The content stresses concrete, actionable guidance: atomics are cheap and atomic per operation but composing atomic steps is non-atomic and requires a mutex (illustrated with an increment example and a Gate using atomic.Bool and CompareAndSwap); use pools to reduce GC pressure; prefer channels or synchronization helpers in tests; and collect CPU profiles, traces and flight recordings for diagnostics using pprof and trace APIs. Practical code snippets demonstrate best practices and cautionary examples so readers can quickly apply or validate concurrent designs and debugging techniques.