The semantics of OPA's policy language are based on Datalog, a non-Turing complete subset of Prolog. This means that all policy queries in OPA are guaranteed to terminate (which makes it a good fit for problems like authorization.)
Beyond regular Datalog, OPA adds first-class support for querying complex/nested data structures like JSON.
As a side note, OPA was not developed at Netflix, but they were one of the early adopters and continue to use it today.
Did you guys build your own engine? I took a quick look at the repo but don't see anything that looks like a datalog library in your glide package list.
Last but not least, thanks for making and open sourcing such an awesome tool! Will definitely be passing the word on about Styra[2], I had no idea there was a whole company/more efforts behind OPA. I plan on using OPA in a bunch of upcoming projects -- it looks like a fantastic, stable addition to the toolbox of people looking to build robust programs/services.
[0]: https://www.youtube.com/watch?v=XEHeexPpgrA
Yes, the language implementation (parser/compiler/evaluator) is implemented from scratch.
> Last but not least, thanks for making and open sourcing such an awesome tool!
Thanks for the kind words! If you have questions or need help, feel free to file issues on Github or ask questions on Slack.