Synchronization

Coordinate Shared State with sync.Cond in Go

A goroutine sometimes cannot make progress until shared state changes. A worker may need to wait until a queue contains an item. A producer may need to wait until that queue has free capacity. Several goroutines may need to sleep until a service becomes ready. Polling the state in a loop wastes CPU or forces you to invent arbitrary sleep intervals. Channels solve many coordination problems more directly, but they are not always a natural fit when several goroutines already share state protected by a mutex and need to wait for predicates over that state.