Mis on kontekst Go-s? Milleks seda kasutatakse? Kuidas töötab ajapiirangu tühistamine?

In Go, context is a package and a concept for managing the lifetime of operations, transmitting cancel signals, and setting time limits between goroutines.

Main tasks of the context:

• Cancel operations (e.g., on timeout or user cancellation),
• Transmit values (e.g., request ID) through the call chain,
• Set time limits (timeouts).

Timeout-based cancellation works as follows:

1. A context with a timeout or deadline is created, for example, context.WithTimeout.
2. When the time expires, the context is automatically canceled.
3. The goroutine listening to this context receives a cancel signal via the Done() channel.
4. The goroutine must handle cancellation properly (e.g., stop work and free resources).

Example:

ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()

select {
case <-time.After(3 * time.Second):
    fmt.Println("operation completed")
case <-ctx.Done():
    fmt.Println("operation canceled or timed out")
}

Here, the operation will be interrupted after 2 seconds if it does not finish earlier.