That is in good shape now, though I worry a bit about how many processes I have broken the work up into. There is a monitor process and then two for each serial port that has servos attached (one reads and the other writes).
I took sample code from "Create custom gym environments from scratch — A stock market example" by Adam King on Medium. That gave me the methods required for a wrapper. That code makes my multiprocess SpiderWhisperer comply with the gym environment API from OpenAI.
In order to have an RL agent learn how to move my spider leg while only developing the sort of familiarity with actual machine-learning math that one gets from sharing a friendly nod across a noisy party, I stripped out pieces of sample code from the Gym tutorial here. That gave me the rest of the code I needed for some conceptual experimental runs.
I hesitate to mention that there was some debugging. Since I am intent on learning from the noble creatures in the phylum arthropoda, I will say that some adjustments to the implementation were required that I discovered by trying to run the RL scenario using code I shuffled together.
Now I am ready to try a long run, and see if an RL Agent that could learn to maneuver a cart up a mountain from a valley, can also learn to make interesting movements with a 4 servo spider leg, without burning out a lot of servos.