Hi. I want to control an iot device that has its own state. I think the best way would be to have a copy of the state in a genserver so I don’t have to retrieve it every time. Simple example is a ligh tbulb with colors. I set the color -the bulb changes it but it’s also saved it the genserver state so I can easily query for it. Other example is a radio that has a menu controlled by api calls. You got the top level menu and can navigate to an menu item. This api call gets me the 10 childs of the parent that I can display and I know that I’m 1 level deep. Again I think I need to keep a copy of the state and not query it after every command. Do you know any libraries that use thes pattern? Or maybe is there any other pattern for this kind of things?
Unless you’re absolutely sure your device can only be accessed by a single GenServer this approach seems Ok: saving state in the process while requesting a change in the device. Otherwise, you might have to ask for a change with “knowledge” of the previous state, e.g. “set color to red if it’s blue”: in this case, if there’s a mismatch with the process state, you should fetch it from the device, store it locally and then do the update. Does this make sense?
You may want to checkout my Lifx library. I haven’t touched it in a while, but it does represent each bulb as a process.
I imagine (with the radio example because it’s more complicated) to have some kind of state hydration logic - I can call it at start/reconnect and then on any connection error. With bulbs it’s not that complicated because the old state does not affect the future state - only problem would be here that my ui won’t be updated when someone else controlls it, Currently I would be the only owner but it would be good to have some checks in place
Thanks. I’ll defenetly check it out.