Go Error Handling Creating an error value
Example
The simplest way to create an error is by using the errors package.
errors.New("this is an error")
If you want to add additional information to an error, the fmt package also provides a useful error creation method:
var f float64
fmt.Errorf("error with some additional information: %g", f)
Here's a full example, where the error is returned from a function:
package main
import (
"errors"
"fmt"
)
var ErrThreeNotFound = errors.New("error 3 is not found")
func main() {
fmt.Println(DoSomething(1)) // succeeds! returns nil
fmt.Println(DoSomething(2)) // returns a specific error message
fmt.Println(DoSomething(3)) // returns an error variable
fmt.Println(DoSomething(4)) // returns a simple error message
}
func DoSomething(someID int) error {
switch someID {
case 3:
return ErrThreeNotFound
case 2:
return fmt.Errorf("this is an error with extra info: %d", someID)
case 1:
return nil
}
return errors.New("this is an error")
}
