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//Author Geoffrrey Hendrey | |
//Here we dynamically invoke a method, passing the method the input, whose type we don't know. We know the method returns two things, a value and an errror. | |
//(multiple return values). This code shows how we grab the error, which | |
//is the second return value of the method, check it it is not nil, and if not nil type-assert it to an actual error (line 11). They key is | |
//on line 11 where we extract the interface() from the errReflect, which is reflect.Value. Once we have an interface{} we can do the type-assertion. | |
func invokeMethod(method reflect.Value, input interface{}) (resp interface{}, err error) { | |
in := []reflect.Value{reflect.ValueOf(input)} | |
returnValuesFromClientCall := method.Call(in) | |
errReflect := returnValuesFromClientCall[1] //this is the error return value from the call above | |
if !errReflect.IsNil() { //if there was an error | |
ifc := errReflect.Interface() | |
err := ifc.(error) | |
log.Errorf("method call returned error: %s", err.Error()) | |
return nil, err | |
} | |
return returnValuesFromClientCall[0].Interface(), nil | |
} |