How does a goroutine recognize that its execution has been canceled via context?

Goroutines in Go recognize cancellation through the context.Context using the Done() channel, which is closed upon cancellation.

When a cancellable context is created (for example, via context.WithCancel or context.WithTimeout), the goroutine can listen to the ctx.Done() channel:

ctx, cancel := context.WithCancel(context.Background())

// Launch goroutine
go func() {
    select {
    case <-ctx.Done():
        // Context is canceled, need to terminate
        fmt.Println("Goroutine canceled")
        return
    default:
        // Perform main work
    }
}()

// Cancel the context
cancel()

Thus, the goroutine detects cancellation by checking the Done() channel and can terminate properly.