Introduce compressor option to ActiveRecord::Encryption::Encryptor

[heka1024]

Motivation / Background

There are more performant algorithms than zlib, like zstd or snappy. So I made it possible to configure the compressor to take advantage of these more performant algorithms.

Detail

Make compressor as argument which default value is zlib.

Additional information

• https://facebook.github.io/zstd/

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one change. Unrelated changes should be opened in separate PRs.
• Commit message has a detailed description of what changed and why. If this PR fixes a related issue include it in the commit message. Ex: [Fix #issue-number]
• Tests are added or updated if you fix a bug or add a feature.
• CHANGELOG files are updated for the changed libraries if there is a behavior change or additional feature. Minor bug fixes and documentation changes should not be included.

Discussion

What do you thinks about make compressor as property of ActiveRecord::Encryption ?

[flavorjones]

The naming of the custom compressor's methods seems inconsistent to me. Would you consider using Encryptor's convention and name them compress/uncompress instead of ZLib's deflate/inflate?

I also think this PR should update the Rails Guides page on encryption, guides/source/active_record_encryption.md to explain how to implement a custom compressor.

[heka1024]

Hi, @flavorjones ! I changed signature of compressor (compress/uncompress) and make compressor configurable. And add some document about compression. Could you review it? I'd really appreciate it if you could provide feedback!

[zzak]

CI failures seem unrelated, you might want to rebase just to be sure as I think most of those have been fixed

[heka1024]

CI failures seem unrelated, you might want to rebase just to be sure as I think most of those have been fixed

@zzak I just rebased it, and it looks like all CI failures are fixed now. 😄

[flavorjones]

OK, so I'm only realizing now that Rails already has prior art for this sort of compression API, see the docs for ActiveSupport::Cache::Store.new and the :compressor option.

In summary, "Must respond to deflate and inflate"

So I hate to ask, especially since I asked you to change it in the first place, but can you update this PR to use that naming convention? I sincerely apologize for not realizing this sooner.

[heka1024]

There is a ci failure but it looks like unrelated.

Failure:
--
  | ActiveRecord::ConnectionAdapters::ReaperTest#test_connection_pool_starts_reaper_in_fork [test/cases/reaper_test.rb:161]:
  | Expected #<Process::Status: pid 79 SIGABRT (signal 6) (core dumped)> to be success?.

[eileencodes]

The feature seems like a good idea to me, thanks for working on it @heka1024

I left a comment about the API design and I also think this should provide a config option so apps that want the same custom compressor for every model can just set it once.

[eileencodes]

This API doesn't feel right. Having to initialize a new Encryptor in your app to set the compressor feels cumbersome and un-Rails like. I have two suggestions:

1. I think if we want a compressor option for every model then Rails should do the initialization for the app. The AR code would check if the compressor option is set and then Rails would do the initialization for the application. Then it's a much cleaner API because it becomes:

encrypts :name, compressor: ZstdCompressor

2. Rails should provide a config option so that applications can set all encryptors to use the same custom compressor.

config.active_record_encryption.compressor = ZstdCompressor

[heka1024]

@eileencodes Thank you for review! Your talk at the 2023 Rails conference inspired me to contribute to Rails, and I'm glad I got a review 😄

1. This API seems nicer than the earlier one. I'll implement it. Additionally, I think we should accept the compress option in the encrypts method, as introduced in Allow encryption without compression #50876. I'll handle that in this PR. So, we can use like this :

encrypts :title, compress: false
encrypts :content, compressor: ZstdCompressor

2. I've already implemented this feature in Config. Should I just add it to the CHANGELOG?

[flavorjones]

@heka1024 New config parameters require a little more documentation work than other features. Specifically, you'll need to update guides/source/configuring.md.

There is a linting tool you should run to make sure configuring.md changes are correct, run tools/railspect configuration .