How do I handle errors with the context package in Go?

How do I handle errors with the context package in Go?

In Go, the context package is used for managing deadlines, cancellation signals, and carrying request-scoped values. To handle errors, you can check if the context has been canceled or if a deadline has exceeded using the context.Context methods.

Can you give me an example of how to check for cancellation?

Sure! You can use the context.Context's Done() method to check for cancellation. Here's a simple example:

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

// Simulate a goroutine that checks for cancellation
go func() {
    select {
    case <-ctx.Done():
        fmt.Println("Context canceled")
    }
}()

// Call cancel to simulate cancellation
cancel()

What should I do if a function returns an error while using context?

If a function returns an error, you should handle it appropriately. You can check if the error is due to context cancellation by comparing it to context.Canceled or context.DeadlineExceeded. Here's an example:

if err := someFunction(ctx); err != nil {
    if errors.Is(err, context.Canceled) {
        fmt.Println("Operation was canceled")
    } else if errors.Is(err, context.DeadlineExceeded) {
        fmt.Println("Operation timed out")
    } else {
        fmt.Println("An error occurred:", err)
    }
}