The Python code generator proved to be very useful.
We generated the REST client code for our production system in Python. Then we programmed a simple user simulator tool in Python (login, do several actions and then after some time: logout and repeat …).
Wonderful: it worked out of the box. Then we transferred the files to our multiple Raspberry PIs available and started the code there. Worked out of the box or to be more precise: concurrency errors showed up at once.
With these results we entered Gemstone programming again and changed the behaviour of the Zinc REST server and introduced automatically repeats of requests and at the end of the day we had only a few errors coming up in the clients – due to concurrency. That seems to be ok.
In our case one PI has to capacity of simulating around 50 concurrent users – we have 5 PIs here available for a testing system … will be fun.