[FR] Allow custom attributes on built-in traces via global attribute API

[jrodiz]

[FR] Allow custom attributes on built-in traces (#6664)

Summary

Resolves #6664

FirebasePerformance already had putAttribute/removeAttribute/getAttribute/getAttributes backed by a ConcurrentHashMap, and TransportManager already attached those global attributes to every logged event — but the four methods were @hide, so developers could not actually set them.

This PR removes the @hide annotations, makes the related constants public, and adds the methods to the public API surface. No behavioral change is needed in the trace/network serialization path — TransportManager.setApplicationInfoAndBuild (firebase-perf/src/main/java/com/google/firebase/perf/transport/TransportManager.java:507-512) already calls putAllCustomAttributes(getGlobalCustomAttributes()) on ApplicationInfo for every trace metric and network request metric.

Where the attributes land

Global attributes attach at the ApplicationInfo.custom_attributes level, not at TraceMetric.custom_attributes / NetworkRequestMetric.custom_attributes. That distinction matters for any consumer reading the proto directly — those are separate proto fields. Trace- and request-level attributes set via Trace.putAttribute / HttpMetric.putAttribute continue to land in their respective per-event custom_attributes map and are independent of the global ones.

Usage

// In Application.onCreate() — set once, applies to all built-in and custom traces
// and to all network requests
FirebasePerformance.getInstance().putAttribute("build_type", "debug");
FirebasePerformance.getInstance().putAttribute("user_tier", "premium");

These attributes will appear on _app_start, _app_in_foreground, _app_in_background, screen traces (_st_*), network requests, and all custom traces automatically — via the existing TransportManager logic.

Notes

• Attribute limit: the global pool is validated at MAX_TRACE_CUSTOM_ATTRIBUTES (5) by FirebasePerformance.putAttribute's existing checkAttribute() call.
• Thread safety: mCustomAttributes is a ConcurrentHashMap; getAttributes() returns a defensive copy.
• Timing for _app_start: global attributes must be set before the trace is built (e.g., in Application.onCreate()).
• Backward compatible: all four methods already existed; only visibility was changed.

Verification

./gradlew :firebase-perf:test

All tests pass locally.

[gemini-code-assist]

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for GitHub and other Google products, sign up here.

[jrodiz]

/gemini review

[gemini-code-assist]

Code Review

This pull request makes global attribute methods and constants public in FirebasePerformance and ensures these attributes are merged into all traces (built-in and custom) and network requests. Feedback suggests enforcing the MAX_TRACE_CUSTOM_ATTRIBUTES limit during the merge process to prevent events from being dropped by the backend and optimizing map allocations by utilizing the defensive copy returned by getAttributes().

[tejasd]

"Global attributes set via these methods are attached to all traces — automatic (for eg. _app_start, screen traces and network traces) and manual."

[jrodiz]

Closing fork PR in favor of: #8162