neighbors barking dog

the dog NEVER shuts up!!!!!!!!!!!!!!!!!!!!!!! It’s a beautiful boxer but the thing is noisy as hell. What can i do about the situation? Should I confront the owners, whom are very nice people, or should I report them? what would you do?
the dog isn’t just barking during the day but all night as well. It’s a fairly quiet neighborhood and everyone around here has a dog or two but this one is ridiculous.