Go Error Handling Returning an error
Example
In Go you don't raise an error. Instead, you return an error in case of failure.
// This method can fail
func DoSomething() error {
// functionThatReportsOK is a side-effecting function that reports its
// state as a boolean. NOTE: this is not a good practice, so this example
// turns the boolean value into an error. Normally, you'd rewrite this
// function if it is under your control.
if ok := functionThatReportsOK(); !ok {
return errors.New("functionThatReportsSuccess returned a non-ok state")
}
// The method succeeded. You still have to return an error
// to properly obey to the method signature.
// But in this case you return a nil error.
return nil
}
If the method returns multiple values (and the execution can fail), then the standard convention is to return the error as the last argument.
// This method can fail and, when it succeeds,
// it returns a string.
func DoAndReturnSomething() (string, error) {
if os.Getenv("ERROR") == "1" {
return "", errors.New("The method failed")
}
s := "Success!"
// The method succeeded.
return s, nil
}
result, err := DoAndReturnSomething()
if err != nil {
panic(err)
}
