docs: add docs for selector, metadata by toddbaert · Pull Request #1829 · open-feature/flagd

toddbaert · 2025-11-27T20:41:02Z

This PR:

adds documentation for our new selector and metadata features, added mostly in feat: multi-project support via selectors and flagSetId namespacing #1702
- conceptual docs
- practical usage docs
- additions to troubleshooting
- migration guide

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gemini-code-assist · 2025-11-27T20:41:17Z

Summary of Changes

Hello @toddbaert, 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 significantly enhances the documentation for flagd's selector features, which allow for more granular and efficient filtering of flag configurations. The updates cover the core concepts of selectors and flag sets, provide practical guidance for their usage, and include a detailed migration path for existing users. Additionally, it addresses potential troubleshooting scenarios and clarifies the syntax and precedence of selectors across various flagd components.

Highlights

New Selector Concepts Documentation: Introduced a new conceptual document explaining flagd's selector features, detailing flag sources, flag sets, metadata reflection, and their decoupling for more flexible flag management.
Migration Guide for Flag Sets: Added a comprehensive guide to assist users in transitioning from legacy source-based selector patterns to the new, recommended flag set-based patterns, ensuring backward compatibility.
Detailed Selector Syntax Reference: Provided a technical specification for selector syntax, including supported keys like flagSetId and source, precedence rules, and how metadata reflection works.
Updated Provider and Sync Configuration Docs: Enhanced existing documentation for provider and sync configurations to reflect the new selector capabilities, including usage examples and precedence for different selector input methods.
Troubleshooting for Selector Issues: Expanded the troubleshooting guide with a dedicated section for common selector-related problems, offering debugging steps for issues like no flags returned, wrong flags, or ignored selectors.

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gemini-code-assist

Code Review

This pull request adds extensive and well-structured documentation for the new selector features, covering concepts, migration, syntax, and troubleshooting. The new documentation is a great addition. I've identified a few minor issues, such as a list numbering error and several instances of trailing whitespace that should be corrected for consistency. More significantly, there's a section on selector precedence in sync-configuration.md that appears to be confusing and potentially incorrect in its context, which I've flagged as a high-severity issue to ensure clarity.

guidobrei

❤️ Fine for me with some suggestions.

One thing we should add in a follow up: All the examples use map-based flag configurations. We do not talk about the possibility of a more flexible flags: [].

guidobrei · 2025-12-16T12:40:50Z

+    }
+  },
+  "metadata": {
+    "flagSetId": "payment-service"  // Reflected from selector


Should we mark this as experimental?
If we decide to support a more flexible selector logic, metadata reflection might not be so easy anymore.

How do you suggest we do so? Since it's a behavior/payload?

toddbaert · 2025-12-17T20:56:51Z

@guidobrei Thanks for the thorough review! 🙏

beeme1mr · 2025-12-22T15:58:45Z

There isn't any mention of the new list-based flag structure. Will that be covered in a follow-up doc? It seems like an important concept because it's the only way to support multiple environment configuration from a single flagd instance

@guidobrei mentioned this too. I will add it.

Added: 7260fad

Signed-off-by: Todd Baert <todd.baert@dynatrace.com>

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com> Signed-off-by: Todd Baert <todd.baert@dynatrace.com>

Signed-off-by: Todd Baert <todd.baert@dynatrace.com>

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com> Signed-off-by: Todd Baert <todd.baert@dynatrace.com>

Signed-off-by: Todd Baert <todd.baert@dynatrace.com>

Co-authored-by: Guido Breitenhuber <guido.breitenhuber@dynatrace.com> Signed-off-by: Todd Baert <todd.baert@dynatrace.com>

Signed-off-by: Todd Baert <todd.baert@dynatrace.com>

sonarqubecloud · 2025-12-22T21:26:05Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

beeme1mr

Looks good but we should release the update before merging this.

toddbaert · 2025-12-23T16:47:52Z

Looks good but we should release the update before merging this.

Yep, agreed.

toddbaert requested review from a team as code owners November 27, 2025 20:41

dosubot Bot added the size:XL This PR changes 500-999 lines, ignoring generated files. label Nov 27, 2025

toddbaert marked this pull request as draft November 27, 2025 20:41

gemini-code-assist Bot reviewed Nov 27, 2025

View reviewed changes