feat: add flagsmith provider

[Zaimwa9]

This PR

• Implements the flagsmith provider for OpenFeature Ruby SDK

Related Issues

Flagsmith issue

Notes

As per an experiment using IA toolings, the code implementation has been 90% done by Claude. Although I have thoroughly supervised and review every step of the process.

Interesting files to grasp the context:

• context.md
• FLAGSMITH_PROVIDER_DESIGN.md
• Readme.md

At flagsmith, we decided to leave all the working files for complete transparency.

Follow-up Tasks

How to test

bundle exec rspec

or

cd providers/openfeature-flagsmith-provider
bundle install
bundle exec rake spec

[gemini-code-assist]

Summary of Changes

Hello @Zaimwa9, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request delivers a new OpenFeature provider for the Flagsmith Ruby SDK. Its primary purpose is to allow Ruby applications to seamlessly integrate with Flagsmith for feature flag management, adhering to the OpenFeature specification. The implementation covers all standard flag types, handles evaluation contexts for user-specific targeting, and incorporates comprehensive error handling and type validation. The PR is accompanied by extensive documentation, including design specifications and usage examples, ensuring clarity and ease of adoption.

Highlights

• New Flagsmith Provider: Introduces a new OpenFeature provider for the Flagsmith Ruby SDK, enabling feature flag management within Ruby applications.
• Comprehensive Design & Implementation: Includes detailed design documents (.context.md, FLAGSMITH_PROVIDER_DESIGN.md) outlining architecture, key decisions, context mapping, error handling, and a thorough testing strategy.
• Full OpenFeature Support: Implements all required OpenFeature flag evaluation methods (boolean, string, number, object) with robust type validation and error handling for seamless integration.
• Flexible Configuration: Supports both remote and optional local evaluation modes, custom API URLs, and analytics configuration through a dedicated Options class.

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[gemini-code-assist]

Code Review

This pull request introduces a new Flagsmith provider for the OpenFeature Ruby SDK. The implementation is comprehensive, including support for all flag types, context mapping, and thorough test coverage. The code is well-structured, with clear separation of concerns for options, errors, and the provider logic itself. I've identified a couple of areas for improvement: one is a potential bug in how evaluation context traits are handled, which could lead to incorrect flag evaluations. The other is an inconsistency between the implementation and the design documents regarding the resolution reason for local evaluation mode. Overall, this is a great contribution.

[Zaimwa9]

@gemini-code-assist, please review again

[gemini-code-assist]

Code Review

This pull request introduces a new Flagsmith provider for the OpenFeature Ruby SDK. The implementation is comprehensive and includes good test coverage. I've found a few areas for improvement:

• A critical bug in numeric value parsing that causes errors for float-like strings.
• An issue where disabled flags are incorrectly reported as not-found. I've suggested a refactoring to correctly handle the DISABLED reason.
• A minor documentation update in the README to include the DISABLED reason.
  Overall, this is a great contribution. Addressing these points will make the provider more robust and compliant with the OpenFeature specification.

[Zaimwa9]

@gemini-code-assist, do you find any critical or high priority issues ?

[gemini-code-assist]

Hello @Zaimwa9, thanks for asking for a follow-up! I've re-reviewed the pull request for critical and high-priority issues.

Overall, the implementation looks solid and well-structured, adhering to the OpenFeature provider patterns. I did not identify any critical issues that would immediately break functionality or introduce severe security flaws.

However, I did find one area that could become a high-priority concern depending on the scale of usage, and another that is a medium-priority maintainability concern:

High Priority (Potential Efficiency Issue)

• Flag Lookup Efficiency: In the evaluate method within lib/openfeature/flagsmith/provider.rb, when fetching non-boolean flags, the code uses flags.all_flags.find { |f| f.feature_name == flag_key } (lines 137-139 in provider.rb).
  • Rationale: If a Flagsmith environment contains a large number of flags (e.g., hundreds or thousands), iterating through all_flags for every flag evaluation can lead to significant performance degradation. This O(N) lookup (where N is the number of flags) can become a bottleneck in high-throughput applications.
  • Suggestion: If the Flagsmith::Flags object provides a more efficient way to look up flags by feature_name (e.g., a hash or map-like access), it would be highly beneficial to use that instead. If not, consider building a Hash map of flags by feature_name once per get_flags call to enable O(1) lookups. This would significantly improve efficiency for environments with many flags.

Medium Priority (Maintainability Issue)

• Broad Exception Handling: The create_flagsmith_client, evaluate, and get_flags methods use broad rescue => e blocks. While these prevent crashes, they can mask specific underlying issues, making debugging more challenging.
  • Rationale: Catching a generic Exception or StandardError can hide more specific errors that might warrant different handling or logging. For example, a FlagsmithClientError could be more specifically handled than a generic StandardError from an unexpected source.
  • Suggestion: Where possible, narrow down the rescue blocks to catch more specific exceptions (as you've done with JSON::ParserError in parse_json_value). For unexpected errors, ensure the error message clearly indicates the original exception type and message to aid in debugging.

I recommend addressing the flag lookup efficiency first, especially if you anticipate a large number of feature flags in your Flagsmith environments. The broad exception handling is also important for long-term maintainability and easier debugging.

[Zaimwa9]

Following latest comment:

• Due to the fact that we are not able to distinguish FLAG_NOT_FOUND vesus FLAG_DISABLED the performance trade-off seems acceptable to me but I leave the decision to the reviewer. We are calling the flagsmith API on each flag evaluation, making a hashmap useless if you want fresh data
• Error => done

[toddbaert]

Taking a look now!

[toddbaert]

@Zaimwa9 Ruby is not my strong suit, but I've reviewed to the best of my ability according to the OpenFeature specification, and this seems good to me.

Before we merge, could you rebase/merge main and add an entry with this component and your name here? This just auto-adds you to PRs for this component.

[Zaimwa9]

@toddbaert, perfect. Thanks for the fast review, I appreciate! All good with the component-owners and rebase. I struggled a bit with DCO but should be good

[alxckn]

Hi 👋 , came across this PR and while it's already been accepted, thought I'd chip in with some potential improvements that stood out to me

[toddbaert]

Hi 👋 , came across this PR and while it's already been accepted, thought I'd chip in with some potential improvements that stood out to me

More than happy for more reviewers - like I said, I'm not a Ruby dev! 🙏

[Zaimwa9]

Addressed @alxckn. By the way, kudos for your help, I appreciate 👍

[alxckn]

LGTM

[Zaimwa9]

@toddbaert, ready to merge :) Thanks for the help