Sometime since I wrote this post about using Google Assistant to open and close my garage door, Google has gone through and added a few more device types. 🆕
Go, check out the post!... tl;dr: in my house, you can say "Ok Google, open the garage door" and the door opens. 🏡🎉
At the time, I used If-This-Then-That. IFTTT is easy, and it just adds random strings to your Google Assistant "profile" that it can match. Additionally, if your Google Home devices have multiple users on them (which in my case they do: myself and my partner), anyone else can trigger these commands too.
So using IFTTT, you could add a command like "Ok Google, do the dishes" which calls a REST API or anything IFTTT can do. But the major downside of IFTTT is that it has no real notion of 'failure': if your REST API returns a 404/500 etc, IFTTT has no real way to pipe that back to you, and will only say one fixed string.
For the more complex approach of devices 'properly' connected to your Assistant account (think light bulbs which are fully integrated into its ecosystem), Google did not yet support the "open" or "close" verbs.
Some folks created posts which talked about how you could control your doors by saying "Ok Google, turn my THING on" or "... THING off" (pretending to be a smart plug), but the verbs don't make sense.
So over the next few days, I'll be working out how to emulate a real device that Google knows about, removing IFTTT support from my door, but emulating an attached device. This is possible because Google now supports: