Metrics for React Native SDK #5402

alwx · 2025-11-24T12:55:55Z

📢 Type of change

Bugfix
New feature
Enhancement
Refactoring

📜 Description

Fixes #5384

This PR does the following:

Adds Metrics API to React Native SDK;
Adds a few tests for Metrics (to make sure Sentry.metrics, enableMetrics flag and beforeSendMetric callback work;
Adds metrics to the sample apps.

💚 How did you test it?

📝 Checklist

I added tests to verify changes
No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled
I updated the docs if needed.
I updated the wizard if needed.
All tests passing
No breaking changes

🔮 Next steps

# Conflicts: # samples/expo/package.json

� Conflicts: � CHANGELOG.md

github-actions · 2025-11-25T09:41:10Z

	Fails
🚫	Pull request is not ready for merge, please add the "ready-to-merge" label to the pull request

Generated by 🚫 dangerJS against 0a27b75

alwx · 2025-11-25T09:44:24Z

samples/expo/app/(tabs)/index.tsx

              Sentry.logger.error('expo error log');

-              Sentry.logger.info('expo info log with data', { database: 'admin', number: 123, obj: { password: 'admin'} });
+              Sentry.logger.info('expo info log with data', { database: 'admin', number: 123, obj: { password: 'admin' } });


Unrelated auto-formatting change

antonis · 2025-11-25T10:47:24Z

@sentry review

sentry · 2025-11-25T10:49:11Z

packages/core/test/metrics.test.ts

+import { getClient, metrics, setCurrentClient } from '@sentry/core';
+import { ReactNativeClient } from '../src/js';
+import { getDefaultTestClientOptions } from './mocks/client';
+import { NATIVE } from './mockWrapper';
+
+jest.mock('../src/js/wrapper', () => jest.requireActual('./mockWrapper'));
+
+const EXAMPLE_DSN = 'https://[email protected]/148053';
+
+describe('Metrics', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+    jest.useFakeTimers();
+    (NATIVE.isNativeAvailable as jest.Mock).mockImplementation(() => true);
+  });
+
+  afterEach(() => {
+    const client = getClient();
+    client?.close();
+    jest.clearAllTimers();
+    jest.useRealTimers();
+  });
+
+  describe('beforeSendMetric', () => {
+    it('is called when enableMetrics is true and a metric is sent', async () => {
+      const beforeSendMetric = jest.fn(metric => metric);
+
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          enableMetrics: true,
+          beforeSendMetric,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      // Send a metric
+      metrics.count('test_metric', 1);
+
+      jest.advanceTimersByTime(10000);
+      expect(beforeSendMetric).toHaveBeenCalled();
+    });
+
+    it('is not called when enableMetrics is false', async () => {
+      const beforeSendMetric = jest.fn(metric => metric);
+
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          enableMetrics: false,
+          beforeSendMetric,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      // Send a metric
+      metrics.count('test_metric', 1);
+
+      jest.advanceTimersByTime(10000);
+      expect(beforeSendMetric).not.toHaveBeenCalled();
+    });
+
+    it('is called when enableMetrics is undefined (metrics are enabled by default)', async () => {
+      const beforeSendMetric = jest.fn(metric => metric);
+
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          beforeSendMetric,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      // Send a metric
+      metrics.count('test_metric', 1);
+
+      jest.advanceTimersByTime(10000);
+      expect(beforeSendMetric).toHaveBeenCalled();
+    });
+
+    it('allows beforeSendMetric to modify metrics when enableMetrics is true', async () => {
+      const beforeSendMetric = jest.fn(metric => {
+        // Modify the metric
+        return { ...metric, name: 'modified_metric' };
+      });
+
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          enableMetrics: true,
+          beforeSendMetric,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      // Send a metric
+      metrics.count('test_metric', 1);
+
+      jest.advanceTimersByTime(10000);
+      expect(beforeSendMetric).toHaveBeenCalled();
+      const modifiedMetric = beforeSendMetric.mock.results[0]?.value;
+      expect(modifiedMetric).toBeDefined();
+      expect(modifiedMetric.name).toBe('modified_metric');
+    });
+
+    it('allows beforeSendMetric to drop metrics by returning null', async () => {
+      const beforeSendMetric = jest.fn(() => null);
+
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          enableMetrics: true,
+          beforeSendMetric,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      // Send a metric
+      metrics.count('test_metric', 1);
+
+      // Advance timers
+      jest.advanceTimersByTime(10000);
+      expect(beforeSendMetric).toHaveBeenCalled();
+      expect(beforeSendMetric.mock.results[0]?.value).toBeNull();
+    });
+  });
+
+  describe('metrics API', () => {
+    it('metrics.count works when enableMetrics is true', () => {
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          enableMetrics: true,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      expect(() => {
+        metrics.count('test_metric', 1);
+      }).not.toThrow();
+    });
+
+    it('metrics can be sent with tags', async () => {
+      const beforeSendMetric = jest.fn(metric => metric);
+
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          enableMetrics: true,
+          beforeSendMetric,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      // Send a metric with tags
+      metrics.count('test_metric', 1, {
+        attributes: { environment: 'test' },
+      });
+
+      jest.advanceTimersByTime(10000);
+      expect(beforeSendMetric).toHaveBeenCalled();
+      const sentMetric = beforeSendMetric.mock.calls[0]?.[0];
+      expect(sentMetric).toBeDefined();
+    });
+  });
+});


The test suite advances timers by 10 seconds (line 40, 62, etc.) expecting metrics to be sent, but there is no verification that the actual metric data reaches the transport layer or that the metrics aggregation completes. Consider adding assertions on the transport mock or verifying that NATIVE.sendEnvelope was called with the expected metric envelope. Additionally, ensure that ReactNativeClient properly inherits metrics support from @sentry/core Client.
_{Severity: MEDIUM}

🤖 Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's not valid. Location: packages/core/test/metrics.test.ts#L1-L180 Potential issue: The test suite advances timers by 10 seconds (line 40, 62, etc.) expecting metrics to be sent, but there is no verification that the actual metric data reaches the transport layer or that the metrics aggregation completes. Consider adding assertions on the transport mock or verifying that `NATIVE.sendEnvelope` was called with the expected metric envelope. Additionally, ensure that `ReactNativeClient` properly inherits metrics support from `@sentry/core` Client.

_{Did we get this right? 👍 / 👎 to inform future reviews.}
_{Reference ID: 3443368}

good point actually

antonis · 2025-11-25T10:59:41Z

samples/react-native/src/App.tsx

+  beforeSendMetric(metric: Sentry.Metric) {
+    logWithoutTracing('Metric beforeSend:', metric.name, metric.value);
+    return metric;
+  },


Wdyt of enabling metrics for the sample app and adding an example in the app (e.g. a button or screen that uses metrics)

Suggested change

},

},

enableMetrics: true,

I am surprised it is not on the experimental field

antonis · 2025-11-25T11:02:43Z

CHANGELOG.md


+### Features
+
+- Adds metrics ([#5402](https://github.com/getsentry/sentry-react-native/pull/5402))


We could mention that the feature is beta (similar to feedback and SR in the past)

Suggested change

- Adds metrics ([#5402](https://github.com/getsentry/sentry-react-native/pull/5402))

- Adds Metrics Beta ([#5402](https://github.com/getsentry/sentry-react-native/pull/5402))

also a small snippet on how to use it would be nice here

@antonis do we want to keep it as beta since it no longer is in beta for JavaScript?

I would advocate towards shipping as beta since the product is still labeled as beta in JS sidebar

antonis

Awesome work @alwx 🎸
Left a few comments/suggestions but overall looks great!

lucas-zimerman · 2025-11-25T15:47:21Z

Sentry docs mention this for JavaScript

Shouldn't we limit it to the experimental field?

EDIT: getsentry/sentry-docs#15632 Lets keep it as is

antonis · 2025-11-25T15:52:43Z

Shouldn't we limit it to the experimental field?

This looks like an oversight in the docs since we don't mention the experimental elsewhere https://docs.sentry.io/platforms/javascript/metrics/ 🤔

lucas-zimerman · 2025-11-25T15:54:27Z

Thank you for the PR!
The PR looks good! before merging, we should enable the ready to ready-to-merge label, and add a basic description on how to enable it and generate a metric.

linear bot mentioned this pull request Nov 24, 2025

Sentry Metrics for React Native #5384

Open

alwx added 4 commits November 25, 2025 10:38

Metrics for React Native SDK

e706613

Fixes

713d146

# Conflicts: # samples/expo/package.json

Fixes, changelog entry

8ccda2b

� Conflicts: � CHANGELOG.md

Metrics changelog

d327971

alwx force-pushed the alwx/feature/metrics branch from 5ce970d to d327971 Compare November 25, 2025 09:40

Smallish fix

b763d55

alwx changed the title ~~WIP: Metrics for React Native SDK~~ Metrics for React Native SDK Nov 25, 2025

alwx commented Nov 25, 2025

View reviewed changes

alwx added 2 commits November 25, 2025 10:46

Lint fix

8a8c1bf

Fix

190a7ba

alwx marked this pull request as ready for review November 25, 2025 10:16

alwx requested review from antonis and lucas-zimerman as code owners November 25, 2025 10:16

Merge branch 'main' into alwx/feature/metrics

0a27b75

sentry bot reviewed Nov 25, 2025

View reviewed changes

antonis reviewed Nov 25, 2025

View reviewed changes


		### Features

		- Adds metrics ([#5402](https://github.com/getsentry/sentry-react-native/pull/5402))

	- Adds metrics ([#5402](https://github.com/getsentry/sentry-react-native/pull/5402))
	- Adds Metrics Beta ([#5402](https://github.com/getsentry/sentry-react-native/pull/5402))

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📝 Checklist

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