func makeTaskDefnInput(jsonPath string) *ecs.RegisterTaskDefinitionInput {
	var defn ecs.RegisterTaskDefinitionInput
	fileBytes, err := ioutil.ReadFile(jsonPath)
	if err != nil {
		log.Println("cannot read task file", err.Error())
		return nil
	}
	err = json.Unmarshal(fileBytes, &defn)
	if err != nil {
		log.Println("cannot parse task file", err.Error())
		return nil
	}
	return &defn

}