canada VS Pundit

While it is definitely possible to roll out something by hand, it usually makes sense not to reinvent the wheel if well-maintained and tested libraries are available. Canada and Bodyguard are two of the more popular ones that I have seen in the community.

There are packages on Hex that haven't been updated in a long time but still work perfectly (Canada, for example: https://github.com/jarednorman/canada). Elixir itself doesn't change much... in fact there's no plans for a 2.0 on the horizon, so the fact that packages don't change often isn't a big deal if they still do what they say they do and aren't hurting for more features.

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.