You can use this but it doesn't really download directly from Spotify. Instead, it takes the song name from Spotify, searches it on YouTube, downloads it from YouTube and then adds metadata from Spotify on the downloaded file.
Shameless self-plug, but I made a Python program that basically does the exact same thing, except it has a web ui. It's called MetaTube and it also supports other metadata providers, such as Musicbrainz and Deezer.