based on @BTallack’s Harmony control box (see: Logitech Harmony Integration with @iandday's component) I have created a Spotify control box.
It allows to select the output target for Spotify using the “Spotify Connect” capability. Home Assistant is fully compatible with Spotify via it’s “spotify:” media_player component. Besides of selecting the output target via the HASS UI, it also adds a volume control and provides some intent_scripts, which allow Echo/Alexa to control your Spotify (even if Spotify is not currently playing via the Echo).
The UI control looks like this:
I’ve uploaded all needed config files to my bitbucket repository. Please be aware, that the configuration.yaml only holds the config lines, that are required for the Spotify stuff. Anything else has been removed for ease of reading. There might also be a better way to implement this, but for me it works fine and is very comfortable (especially with Alexa)… Imagine coming home from work and while storing your bike, you say: “Alexa, ask Home Assistant to play spotify on the livingroom PC”
Maybe someone finds this interesting and helpful.