https://www.theverge.com/2018/7/31/17635102/google-clock-spotify-alarm-morning-sounds

At long last, Google is making it super easy for you to set music as your alarm sound in the Clock app. By way of a new update that’s starting to roll out today, users will be able to connect their Spotify accounts to the clock app and wake up to their favorite playlists and songs.

This new update will let Spotify Free and Premium users integrate the music streaming app into the alarm sounds section on Google Clock. There, they will be able to select between two tabs for picking alarm sounds, including the familiar alert tones and now an entirely separate set of options for Spotify. After navigating to the Spotify section, users can pick music from a variety of pre-made morning-themed Spotify playlists or choose from music that they have recently listened to through the app.