> And then you start to think about caching, data consistency, and so on
If you are looking at OPA or Cedar as a standalone engine, this is the correct assumption. To avoid this hassle, there is an open-source tool called OPAL[1] that will let you run the policy engines with all the sync work without any investment in custom solutions. OPAL has a ready mechanism for data fetching and synchronization, so you can plug it into your application's data and not worry about the data.
If you are looking at OPA or Cedar as a standalone engine, this is the correct assumption. To avoid this hassle, there is an open-source tool called OPAL[1] that will let you run the policy engines with all the sync work without any investment in custom solutions. OPAL has a ready mechanism for data fetching and synchronization, so you can plug it into your application's data and not worry about the data.
Disclaimer: I'm one of the OPA maintainers.
[1] https://github.com/permitio/opal