How to return an error from a function in Go?

In Go, returning an error from a function is a common and idiomatic way of handling errors. Here's how you can return an error from a function in Go:

Define an error type:

type MyError struct {
    Message string
}

Implement the error interface for the error type:

func (e *MyError) Error() string {
    return e.Message
}

Use the error type in your function and return an instance of it when an error occurs:

func doSomething() error {
    // If an error occurs, return an instance of the error type
    if condition {
        return &MyError{
            Message: "Something went wrong",
        }
    }

    // No error, return nil
    return nil
}

In the calling code, check if an error was returned and handle it accordingly:

err := doSomething()
if err != nil {
    // Handle the error
    fmt.Println(err)
}

This way, your function doSomething can indicate that an error occurred by returning a non-nil error value of the appropriate type, and the calling code can react accordingly.