The rapper's attorney, Bradford Cohen, tells TMZ ... Kodak's been sentenced to nearly 4 years in prison after he pled guilty in his federal gun case back in August. Kodak's also been sentenced to 3 years of supervised release.

It's a bit of a break considering prosecutors wanted 96 months after Kodak was involved in a fight behind bars which resulted in a prison guard getting hurt.

As we reported ... as part of Kodak's plea agreement, prosecutors said they would push for a lighter sentence because Kodak had been cooperative. He initially faced a maximum of 10 years after pleading guilty to 2 counts of knowingly making a false and fictitious written statement in connection with the acquisition of a firearm.

Kodak had been in federal custody since his arrest in May. He had wanted to be let out while the case unfolded but a judge denied his request for bail after calling him a danger to the community.

The rapper had been arrested at the Rolling Loud festival on arrest warrants stemming from his indictment.