oso VS Pundit

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Not OP but Authentication is easy, authorization is a cross-cutting concern that often requires custom code. E.g., there are people and teams, both of which can have different kinds of access to something (read/write). Sometimes teams have sub-teams. Do the sub-teams have access to the parent teams' resources and/or vice versa? Also what kind of sharing are you going to support? Do people have to have an account to view stuff shared to them or can you just send a link? There are some efforts to make custom DSLs for describing authorization policies, to avoid cross-cutting code[1].

Computed fields require different treatment at every level of the stack. This isn't inherently hard, but it is an extra feature these low-code/no-code platforms need. Where things get difficult is inn migrations. It's common for a field that is computed at the beginning to become customizable, or for the computation to change. When that happens, what should the value be for old columns? Computed fields also often pull data from multiple other tables, which may require some combination of custom queries and database optimization.

[1] https://github.com/osohq/oso

Oso and OpenFGA are two alternatives that implement Zanzibar-style authorisation.

There's Oso as well

Well this was fun to see! I'm the CTO of Oso, where we're building Polar (the second of the links mentioned https://docs.osohq.com/).

I have a few really minor nitpicks, so will try and make up for it by adding to the discussion :)

First of all, it doesn't really make sense to talk about Datalog as a good language for authorization, because much like with Prolog there doesn't really exist a single implementation of it. OPA's language Rego is a datalog variant, and Polar started out as a Prolog variant (although it's not really recognisable as one any more).

And that's an important point because otherwise it would be pretty reasonable to decide that: logic programming is good for authorization => you should go find the most battle-tested language out there and use that. For example, there's SWI Prolog [1] and Scryer Prolog [2] as two of my favourites.

To me, the thing that is mind-blowing about logic programming, is (a) how powerful the paradigm is, and (b) how concisely you can implement a logic programming language. Take miniKanren [3] which is a full-blown logic language in a few hundred lines of code.

In my mind, the original article makes a decent case that logic programming is a good fit for authorization. And just generally I love anyone bringing attention to that :)

But to me, the reason logic programming is such a solid foundation for authorization logic is the pieces you can build on top of it. For Polar, we've added:

- Types! So you can write authorization logic over your data types and help structure your logic. We've implemented this by simply adding an additional operator into the language that can check types

First time hearing about rhai, but there's a project in that space called Oso that's authored in Rust and uses a different DSL than Rego. You may or may not find it appealing.

Authentication is probably the aspect of it that's the weakest. Authorization has a few nice libs, with Oso probably being the nicest, but authentication is mostly roll your own from what I've seen.

> Hopefully Oso open source their library.

https://github.com/osohq/oso seems to have the core, C FFI, and language bindings.

Thanks! PHP is a highly requested language for us and we've been rolling them out based on demand. You can vote for it if you want here https://github.com/osohq/oso/issues/791

https://github.com/varvet/pundit Popular open-source Ruby library focused around the notion of policies, giving you the freedom to implement your own approach based on that.

Can you expand a little? Here's some technical background on what we're doing:

We have our own database of every version of every rubygems package alongside its runtime dependencies (like you see at https://rubygems.org/gems/pundit).

Then we parse your Gemfile and Gemfile.lock. We use the Gemfile to figure out gem group and pinned requirements (we run turn your Gemfile into a ruby AST since Gemfiles can be arbitrary ruby code; we use bundler's APIs to parse your Gemfile.lock). This gives us all of the dependencies your rely on.

Then we let you choose one or more package that you want to upgrade and the version you want to target (let's say Rails 7.0.4.3).

Now we have [your dependencies and their current versions], [target rails version], [all of the runtime dependency constraints of these gems]. We run this through a dependency resolution algorithm (pubgrub). If it resolves then you're good to upgrade to that version of Rails without changing anything.

If this fails to resolve, it's because one or more of your current dependencies has a runtime restriction on rails (or another indirect gem being pulled in by the new rails version). This is where the optimization part comes in. The problem becomes "what is the optimal set of versions of all your dependencies that would resolve with the next version of Rails". Currently we solve for this set trying to optimize for the fewest upgrades. As our dataset of breaking changes gets better we'll change that to optimizing for the "lowest effort".

Happy to elaborate.

For authorization, I'm going back and forth with Pundit and CanCanCan

Expressing authorization rules can be a bit challenging with the use of other authorization gems, such as pundit or cancancan. The resource_policy gem provides a more concise and expressive policy definition that uses a simple block-based syntax that makes it easy to understand and write authorization rules for each attribute.

As an example of how to default to deny, consider a Ruby on Rails app (as we tend to do). The primary way a user interacts with the app is through API endpoints powered by controllers. We use Pundit, a popular authorization library for Rails, to manage user permissions.

https://github.com/varvet/pundit Popular open-source Ruby library focused around the notion of policies, giving you the freedom to implement your own approach based on that.

PS If you do mobile / web work (or something else with "detached" UI), I find that declarative access control rules are far superior to imperative ones, because they can be serialized and shipped over the wire. For example, backend running cancancan can be easily send the same rules to casl on the frontend, while if you used something like pundit to secure your backend, you either end up re-implementing it in the frontend, or sending ton of "canEdit" flags with every record.

You can use a combination of an authorization gem (https://github.com/varvet/pundit) and decorators (https://www.rubyguides.com/2018/04/decorator-pattern-in-ruby/) if you want to extend functionality based on their roles.

Use Action Policy or Pundit, and write tests for your policies. Authz is worth testing with near complete coverage.