My web app will (hopefully) use dynamic layers with symbols that are rendered dynamically, based on a user chosen attribute. So far I am doing this by defining a UniqueValueRenderer, then passing these properties to a layer with LayerDrawingOptions. My work so far is loosely based on this example.
I periodically add new layers to the map and then re-publish them with a Python script using ArcPy. As far as I know, ArcPy does not provide a way to overwrite an existing map service (please correct me if I am wrong! ) So instead, I delete, then publish, the map service from scratch.
So here is my issue: to allow dynamic symbol rendering in my map services, I need to enable per request modification of the services, which I can do in Manager for the services on that server (see image below). But, I have not found a way to do this with ArcPy. Once the map services are re-published, as of now I need to then log into Manger and manually check the 'allow modification' checkbox, and also re-register the file gdb as a dynamic workspace. I have several map services in this app that need to redner symbols dynamically. (This question is also posted on ESRI's Geonet here