getsentry · aliu39 · Oct 29, 2024 · Oct 29, 2024 · Oct 29, 2024 · Oct 29, 2024
diff --git a/...ges/browser-integration-tests/suites/integrations/featureFlags/launchdarkly/basic/test.ts b/...ges/browser-integration-tests/suites/integrations/featureFlags/launchdarkly/basic/test.ts
@@ -0,0 +1,43 @@
+import { expect } from '@playwright/test';
+
+import { sentryTest } from '../../../../../utils/fixtures';
+
+import { envelopeRequestParser, waitForErrorRequest } from '../../../../../utils/helpers';
+import { FLAG_BUFFER_SIZE } from '@sentry/browser';
+
+sentryTest('Basic test with eviction, update, and no async tasks', async ({ getLocalTestPath, page }) => {
+  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 getLocalTestPath({ testDir: __dirname, skipDsnRouteHandler: true });
+  await page.goto(url);
+
+  await page.waitForFunction((bufferSize) => {
+    const ldClient = (window as any).initializeLD();
+    for (let i = 1; i <= bufferSize; i++) {
+      ldClient.variation(`feat${i}`, false);
+    }
+    ldClient.variation(`feat${bufferSize + 1}`, true); // eviction
+    ldClient.variation('feat3', true);   // update
+    return true;
+  }, FLAG_BUFFER_SIZE);
+
+  const reqPromise = waitForErrorRequest(page);
+  await page.locator('#error').click();
+  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/launchdarkly/init.js b/dev-packages/browser-integration-tests/suites/integrations/featureFlags/launchdarkly/init.js
@@ -0,0 +1,39 @@
+import * as Sentry from '@sentry/browser';
+import { launchDarklyIntegration, buildLaunchDarklyFlagUsedHandler } from '@sentry/browser';
+
+window.Sentry = Sentry;
+window.sentryLDIntegration = launchDarklyIntegration();
+
+Sentry.init({
+  dsn: 'https://[email protected]/1337',
+  sampleRate: 1.0,
+  integrations: [window.sentryLDIntegration],
+});
+
+// Manually mocking this because LD only has mock test utils for the React SDK.
+// Also, no SDK has mock utils for FlagUsedHandler's.
+const MockLaunchDarkly = {
+  initialize(_clientId, context, options) {
+    const flagUsedHandler = (options && options.inspectors) ? options.inspectors[0].method : undefined;
+
+    return {
+      variation(key, defaultValue) {
+        if (flagUsedHandler) {
+          flagUsedHandler(key, { value: defaultValue }, context);
+        }
+        return defaultValue;
+      },
+    };
+  },
+};
+
+window.ldClient = undefined;
+
+window.initializeLD = () => {
+  window.ldClient = MockLaunchDarkly.initialize(
+    'example-client-id',
+    { kind: 'user', key: 'example-context-key' },
+    { inspectors: [buildLaunchDarklyFlagUsedHandler()] },
+  );
+  return window.ldClient;
+};
diff --git a/...ckages/browser-integration-tests/suites/integrations/featureFlags/launchdarkly/subject.js b/...ckages/browser-integration-tests/suites/integrations/featureFlags/launchdarkly/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/launchdarkly/template.html b/...ges/browser-integration-tests/suites/integrations/featureFlags/launchdarkly/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/launchdarkly/withScope/test.ts b/...browser-integration-tests/suites/integrations/featureFlags/launchdarkly/withScope/test.ts
@@ -0,0 +1,66 @@
+import { expect } from '@playwright/test';
+
+import { sentryTest } from '../../../../../utils/fixtures';
+
+import { envelopeRequestParser, waitForErrorRequest } from '../../../../../utils/helpers';
+
+import type { Scope } from '@sentry/browser';
+
+sentryTest('Flag evaluations in forked scopes are stored separately.', async ({ getLocalTestPath, page }) => {
+  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 getLocalTestPath({ 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);
+
+  const hasButton = await page.evaluate(() => {
+    const Sentry = (window as any).Sentry;
+    const errorButton = document.querySelector('#error');
+    if (!(errorButton instanceof HTMLButtonElement)) {
+      return false;
+    }
+    const ldClient = (window as any).initializeLD();
+
+    ldClient.variation('shared', true);
+
+    Sentry.withScope((scope: Scope) => {
+      ldClient.variation('forked', true);
+      ldClient.variation('shared', false);
+      scope.setTag('isForked', true);
+      errorButton.click();
+    });
+
+    ldClient.variation('main', true);
+    Sentry.getCurrentScope().setTag('isForked', false);
+    errorButton.click();
+    return true;
+  });
+
+  if (!hasButton) {
+    throw new Error('Expected template to have a button that throws an error')
+  }
+
+  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
@@ -75,3 +75,5 @@ export type { Span } from '@sentry/types';
 export { makeBrowserOfflineTransport } from './transports/offline';
 export { browserProfilingIntegration } from './profiling/integration';
 export { spotlightBrowserIntegration } from './integrations/spotlight';
+export { launchDarklyIntegration, buildLaunchDarklyFlagUsedHandler } from './integrations/featureFlags/launchdarkly';
+export { FLAG_BUFFER_SIZE } from './utils/featureFlags';
diff --git a/packages/browser/src/integrations/featureFlags/launchdarkly/index.ts b/packages/browser/src/integrations/featureFlags/launchdarkly/index.ts
@@ -0,0 +1 @@
+export {launchDarklyIntegration, buildLaunchDarklyFlagUsedHandler} from './integration';
diff --git a/packages/browser/src/integrations/featureFlags/launchdarkly/integration.ts b/packages/browser/src/integrations/featureFlags/launchdarkly/integration.ts
@@ -0,0 +1,68 @@
+import type { Client, Event, EventHint, IntegrationFn } from '@sentry/types';
+import type { LDContext, LDEvaluationDetail, LDInspectionFlagUsedHandler } from './types';
+
+import { insertToFlagBuffer } from '../../../utils/featureFlags'
+import { defineIntegration, getCurrentScope } from '@sentry/core';
+
+/**
+ * Sentry integration for capturing feature flags from LaunchDarkly.
+ *
+ * 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 {launchDarklyIntegration, buildLaunchDarklyFlagUsedInspector} from '@sentry/browser';
+ * import * as LaunchDarkly from 'launchdarkly-js-client-sdk';
+ *
+ * Sentry.init(..., integrations: [launchDarklyIntegration()])
+ * const ldClient = LaunchDarkly.initialize(..., {inspectors: [buildLaunchDarklyFlagUsedHandler()]});
+ * ```
+ */
+export const launchDarklyIntegration = defineIntegration(() => {
+  return {
+    name: 'LaunchDarkly',
+
+    processEvent(event: Event, _hint: EventHint, _client: Client): Event {
+      const scope = getCurrentScope();
+      const flagContext = scope.getScopeData().contexts.flags;
+      const flagBuffer = flagContext ? flagContext.values : [];
+
+      if (event.contexts === undefined) {
+        event.contexts = {};
+      }
+      event.contexts.flags = { values: [...flagBuffer] };
+      return event;
+    },
+  };
+}) satisfies IntegrationFn;
+
+/**
+ * LaunchDarkly hook that listens for flag evaluations and updates the `flags`
+ * context in our Sentry scope. This needs to be registered as an
+ * 'inspector' in LaunchDarkly initialize() options, separately from
+ * `launchDarklyIntegration`. Both are needed to collect feature flags on error.
+ */
+export function buildLaunchDarklyFlagUsedHandler(): LDInspectionFlagUsedHandler {
+  return {
+    name: 'sentry-flag-auditor',
+    type: 'flag-used',
+
+    synchronous: true,
+
+    /**
+     * Handle a flag evaluation by storing its name and value on the current scope.
+     */
+    method: (flagKey: string, flagDetail: LDEvaluationDetail, _context: LDContext) => {
+      if (typeof flagDetail.value === 'boolean') {
+        const scopeContexts = getCurrentScope().getScopeData().contexts;
+        if (!scopeContexts.flags) {
+          scopeContexts.flags = { values: [] };
+        }
+        const flagBuffer = scopeContexts.flags.values;
+        insertToFlagBuffer(flagBuffer, flagKey, flagDetail.value);
+      }
+      return;
+    },
+  };
+}
diff --git a/packages/browser/src/integrations/featureFlags/launchdarkly/types.ts b/packages/browser/src/integrations/featureFlags/launchdarkly/types.ts
@@ -0,0 +1,50 @@
+/**
+ * Inline definitions of LaunchDarkly types so we don't have to include their
+ * SDK in devDependencies. These are only for type-checking and can be extended
+ * as needed - for exact definitions, reference `launchdarkly-js-client-sdk`.
+ */
+
+/**
+ * Currently, the Sentry integration does not read from values of this type.
+ */
+export type LDContext = object;
+
+/**
+ * An object that combines the result of a feature flag evaluation with information about
+ * how it was calculated.
+ */
+export interface LDEvaluationDetail {
+  value: unknown;
+  // unused optional props: variationIndex and reason
+}
+
+/**
+ * Callback interface for collecting information about the SDK at runtime.
+ *
+ * This interface is used to collect information about flag usage.
+ *
+ * This interface should not be used by the application to access flags for the purpose of controlling application
+ * flow. It is intended for monitoring, analytics, or debugging purposes.
+ */
+export interface LDInspectionFlagUsedHandler {
+  type: 'flag-used';
+
+  /**
+   * Name of the inspector. Will be used for logging issues with the inspector.
+   */
+  name: string;
+
+  /**
+   * If `true`, then the inspector will be ran synchronously with evaluation.
+   * Synchronous inspectors execute inline with evaluation and care should be taken to ensure
+   * they have minimal performance overhead.
+   */
+  synchronous?: boolean;
+
+  /**
+   * This method is called when a flag is accessed via a variation method, or it can be called based on actions in
+   * wrapper SDKs which have different methods of tracking when a flag was accessed. It is not called when a call is made
+   * to allFlags.
+   */
+  method: (flagKey: string, flagDetail: LDEvaluationDetail, context: LDContext) => void;
+}
diff --git a/packages/browser/src/utils/featureFlags.ts b/packages/browser/src/utils/featureFlags.ts
@@ -0,0 +1,59 @@
+import type { FeatureFlag } from '@sentry/types';
+import { logger } from '@sentry/utils';
+import { DEBUG_BUILD } from '../debug-build';
+
+/**
+ * Ordered LRU cache for storing feature flags in the scope context. The name
+ * of each flag in the buffer is unique, and the output of getAll() is ordered
+ * from oldest to newest.
+ */
+
+/**
+ * Max size of the LRU flag buffer stored in Sentry scope and event contexts.
+ */
+export const FLAG_BUFFER_SIZE = 100;
+
+/**
+ * Insert into a FeatureFlag array while maintaining ordered LRU properties. Not
+ * thread-safe. After inserting:
+ * - `flags` is sorted in order of recency, with the newest flag at the end.
+ * - No other flags with the same name exist in `flags`.
+ * - The length of `flags` does not exceed `maxSize`. The oldest flag is evicted
+ *  as needed.
+ *
+ * @param flags    The array to insert into.
+ * @param name     Name of the feature flag to insert.
+ * @param value    Value of the feature flag.
+ * @param maxSize  Max number of flags the buffer should store. It's recommended
+ *   to keep this consistent across insertions. Default is DEFAULT_MAX_SIZE
+ */
+export function insertToFlagBuffer(
+  flags: FeatureFlag[],
+  name: string,
+  value: boolean,
+  maxSize: number = FLAG_BUFFER_SIZE,
+): void {
+  if (flags.length > maxSize) {
+    DEBUG_BUILD && logger.error(`insertToFlagBuffer called on a buffer larger than the given maxSize=${maxSize}`);
+    return;
+  }
+
+  // Check if the flag is already in the buffer - O(n)
+  const index = flags.findIndex(f => f.flag === name);
+
+  if (index !== -1) {
+    // The flag was found, remove it from its current position - O(n)
+    flags.splice(index, 1);
+  }
+
+  if (flags.length === maxSize) {
+    // If at capacity, pop the earliest flag - O(n)
+    flags.shift();
+  }
+
+  // Push the flag to the end - O(1)
+  flags.push({
+    flag: name,
+    result: value,
+  });
+}