Judge David Sharp also highlighted alcohol issues for which Diamond would attend counselling.
A$AP Rocky - whose real name is Rakim Mayers - had just performed a one-off show at Vector Arena and was getting into a lift with a group of women when the alleged incident happened, celebrity-gossip website TMZ reported.
Three men allegedly tried to join them and a brawl erupted. Hotel security intervened until police arrived.
During the melee, witnesses said they heard cries of "F**k A$AP" but Diamond previously told the Herald he and his friends didn't know the musician and were simply staying at the hotel.
"It was probably over nothing, really," he said.
Diamond, listed in court documents as a bouncer from South Auckland, claimed the tussle had already started before he entered the scene. "There was no drama, no one trying to get jealous of girls or anything," he said.
The court heard today that a police officer had sustained injuries to his finger and forearm in the aftermath, after Diamond wielded a broken bottle.
However, it appears the pair have put that behind them.
Judge Sharp said a restorative-justice conference between the defendant and the officer had been "very successful".
"If you can measure your own behaviour against that of the police officer, you'll be going a long way to addressing your own issues," he said.
Diamond, who calls himself "Otara's favourite son and New Zealand's realest MC" on music websites, will serve his sentence at a Papatoetoe address.
Judge Sharp ordered him to pay $750 - at $25 a fortnight - to the victim for the emotional harm caused.