feat(flags): Add featureFlagsIntegration for custom tracking of flag …

…evaluations (#14582) Follow-up to #14207. Sentry integration for buffering feature flags manually with an API and auto-capturing them on error events.
getsentry · Dec 6, 2024 · a985d64 · a985d64
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diff --git a/...ges/browser-integration-tests/suites/integrations/featureFlags/featureFlags/basic/test.ts b/...ges/browser-integration-tests/suites/integrations/featureFlags/featureFlags/basic/test.ts
@@ -0,0 +1,48 @@
+import { expect } from '@playwright/test';
+
+import { sentryTest } from '../../../../../utils/fixtures';
+
+import { envelopeRequestParser, shouldSkipFeatureFlagsTest, waitForErrorRequest } from '../../../../../utils/helpers';
+
+const FLAG_BUFFER_SIZE = 100; // Corresponds to constant in featureFlags.ts, in browser utils.
+
+sentryTest('Basic test with eviction, update, and no async tasks', async ({ getLocalTestUrl, page }) => {
+  if (shouldSkipFeatureFlagsTest()) {
+    sentryTest.skip();
+  }
+
+  await page.route('https://dsn.ingest.sentry.io/**/*', route => {
+    return route.fulfill({
+      status: 200,
+      contentType: 'application/json',
+      body: JSON.stringify({ id: 'test-id' }),
+    });
+  });
+
+  const url = await getLocalTestUrl({ testDir: __dirname, skipDsnRouteHandler: true });
+  await page.goto(url);
+
+  await page.evaluate(bufferSize => {
+    const flagsIntegration = (window as any).Sentry.getClient().getIntegrationByName('FeatureFlags');
+    for (let i = 1; i <= bufferSize; i++) {
+      flagsIntegration.addFeatureFlag(`feat${i}`, false);
+    }
+    flagsIntegration.addFeatureFlag(`feat${bufferSize + 1}`, true); // eviction
+    flagsIntegration.addFeatureFlag('feat3', true); // update
+    return true;
+  }, FLAG_BUFFER_SIZE);
+
+  const reqPromise = waitForErrorRequest(page);
+  await page.locator('#error').click(); // trigger error
+  const req = await reqPromise;
+  const event = envelopeRequestParser(req);
+
+  const expectedFlags = [{ flag: 'feat2', result: false }];
+  for (let i = 4; i <= FLAG_BUFFER_SIZE; i++) {
+    expectedFlags.push({ flag: `feat${i}`, result: false });
+  }
+  expectedFlags.push({ flag: `feat${FLAG_BUFFER_SIZE + 1}`, result: true });
+  expectedFlags.push({ flag: 'feat3', result: true });
+
+  expect(event.contexts?.flags?.values).toEqual(expectedFlags);
+});
diff --git a/dev-packages/browser-integration-tests/suites/integrations/featureFlags/featureFlags/init.js b/dev-packages/browser-integration-tests/suites/integrations/featureFlags/featureFlags/init.js
@@ -0,0 +1,12 @@
+import * as Sentry from '@sentry/browser';
+
+window.Sentry = Sentry;
+
+// Not using this as we want to test the getIntegrationByName() approach
+// window.sentryFeatureFlagsIntegration = Sentry.featureFlagsIntegration();
+
+Sentry.init({
+  dsn: 'https://[email protected]/1337',
+  sampleRate: 1.0,
+  integrations: [Sentry.featureFlagsIntegration()],
+});
diff --git a/...ckages/browser-integration-tests/suites/integrations/featureFlags/featureFlags/subject.js b/...ckages/browser-integration-tests/suites/integrations/featureFlags/featureFlags/subject.js
@@ -0,0 +1,3 @@
+document.getElementById('error').addEventListener('click', () => {
+  throw new Error('Button triggered error');
+});
diff --git a/...ges/browser-integration-tests/suites/integrations/featureFlags/featureFlags/template.html b/...ges/browser-integration-tests/suites/integrations/featureFlags/featureFlags/template.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8" />
+  </head>
+  <body>
+    <button id="error">Throw Error</button>
+  </body>
+</html>
diff --git a/...browser-integration-tests/suites/integrations/featureFlags/featureFlags/withScope/test.ts b/...browser-integration-tests/suites/integrations/featureFlags/featureFlags/withScope/test.ts
@@ -0,0 +1,65 @@
+import { expect } from '@playwright/test';
+
+import { sentryTest } from '../../../../../utils/fixtures';
+
+import { envelopeRequestParser, shouldSkipFeatureFlagsTest, waitForErrorRequest } from '../../../../../utils/helpers';
+
+import type { Scope } from '@sentry/browser';
+
+sentryTest('Flag evaluations in forked scopes are stored separately.', async ({ getLocalTestUrl, page }) => {
+  if (shouldSkipFeatureFlagsTest()) {
+    sentryTest.skip();
+  }
+
+  await page.route('https://dsn.ingest.sentry.io/**/*', route => {
+    return route.fulfill({
+      status: 200,
+      contentType: 'application/json',
+      body: JSON.stringify({ id: 'test-id' }),
+    });
+  });
+
+  const url = await getLocalTestUrl({ testDir: __dirname, skipDsnRouteHandler: true });
+  await page.goto(url);
+
+  const forkedReqPromise = waitForErrorRequest(page, event => !!event.tags && event.tags.isForked === true);
+  const mainReqPromise = waitForErrorRequest(page, event => !!event.tags && event.tags.isForked === false);
+
+  await page.evaluate(() => {
+    const Sentry = (window as any).Sentry;
+    const errorButton = document.querySelector('#error') as HTMLButtonElement;
+    const flagsIntegration = (window as any).Sentry.getClient().getIntegrationByName('FeatureFlags');
+
+    flagsIntegration.addFeatureFlag('shared', true);
+
+    Sentry.withScope((scope: Scope) => {
+      flagsIntegration.addFeatureFlag('forked', true);
+      flagsIntegration.addFeatureFlag('shared', false);
+      scope.setTag('isForked', true);
+      if (errorButton) {
+        errorButton.click();
+      }
+    });
+
+    flagsIntegration.addFeatureFlag('main', true);
+    Sentry.getCurrentScope().setTag('isForked', false);
+    errorButton.click();
+    return true;
+  });
+
+  const forkedReq = await forkedReqPromise;
+  const forkedEvent = envelopeRequestParser(forkedReq);
+
+  const mainReq = await mainReqPromise;
+  const mainEvent = envelopeRequestParser(mainReq);
+
+  expect(forkedEvent.contexts?.flags?.values).toEqual([
+    { flag: 'forked', result: true },
+    { flag: 'shared', result: false },
+  ]);
+
+  expect(mainEvent.contexts?.flags?.values).toEqual([
+    { flag: 'shared', result: true },
+    { flag: 'main', result: true },
+  ]);
+});
diff --git a/packages/browser/src/index.ts b/packages/browser/src/index.ts
@@ -69,5 +69,9 @@ export { makeBrowserOfflineTransport } from './transports/offline';
 export { browserProfilingIntegration } from './profiling/integration';
 export { spotlightBrowserIntegration } from './integrations/spotlight';
 export { browserSessionIntegration } from './integrations/browsersession';
+export {
+  featureFlagsIntegration,
+  type FeatureFlagsIntegration,
+} from './integrations/featureFlags';
 export { launchDarklyIntegration, buildLaunchDarklyFlagUsedHandler } from './integrations/featureFlags/launchdarkly';
 export { openFeatureIntegration, OpenFeatureIntegrationHook } from './integrations/featureFlags/openfeature';
diff --git a/packages/browser/src/integrations/featureFlags/featureFlagsIntegration.ts b/packages/browser/src/integrations/featureFlags/featureFlagsIntegration.ts
@@ -0,0 +1,47 @@
+import type { Client, Event, EventHint, Integration, IntegrationFn } from '@sentry/core';
+
+import { defineIntegration } from '@sentry/core';
+import { copyFlagsFromScopeToEvent, insertFlagToScope } from '../../utils/featureFlags';
+
+export interface FeatureFlagsIntegration extends Integration {
+  addFeatureFlag: (name: string, value: unknown) => void;
+}
+
+/**
+ * Sentry integration for buffering feature flags manually with an API, and
+ * capturing them on error events. We recommend you do this on each flag
+ * evaluation. Flags are buffered per Sentry scope and limited to 100 per event.
+ *
+ * See the [feature flag documentation](https://develop.sentry.dev/sdk/expected-features/#feature-flags) for more information.
+ *
+ * @example
+ * ```
+ * import * as Sentry from '@sentry/browser';
+ * import { type FeatureFlagsIntegration } from '@sentry/browser';
+ *
+ * // Setup
+ * Sentry.init(..., integrations: [Sentry.featureFlagsIntegration()])
+ *
+ * // Verify
+ * const flagsIntegration = Sentry.getClient()?.getIntegrationByName<FeatureFlagsIntegration>('FeatureFlags');
+ * if (flagsIntegration) {
+ *   flagsIntegration.addFeatureFlag('my-flag', true);
+ * } else {
+ *   // check your setup
+ * }
+ * Sentry.captureException(Exception('broke')); // 'my-flag' should be captured to this Sentry event.
+ * ```
+ */
+export const featureFlagsIntegration = defineIntegration(() => {
+  return {
+    name: 'FeatureFlags',
+
+    processEvent(event: Event, _hint: EventHint, _client: Client): Event {
+      return copyFlagsFromScopeToEvent(event);
+    },
+
+    addFeatureFlag(name: string, value: unknown): void {
+      insertFlagToScope(name, value);
+    },
+  };
+}) as IntegrationFn<FeatureFlagsIntegration>;
diff --git a/packages/browser/src/integrations/featureFlags/index.ts b/packages/browser/src/integrations/featureFlags/index.ts
@@ -0,0 +1 @@
+export { featureFlagsIntegration, type FeatureFlagsIntegration } from './featureFlagsIntegration';
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		export { featureFlagsIntegration, type FeatureFlagsIntegration } from './featureFlagsIntegration';