feat: Add Fastly Edge SDK

packages/sdk/fastly/README.md

@@ -2,13 +2,6 @@
 
 The LaunchDarkly SDK for Fastly is designed for use in [Fastly Compute Platform](https://www.fastly.com/documentation/guides/compute/). It follows the server-side LaunchDarkly model for multi-user contexts. It is not intended for use in desktop and embedded systems applications.
 
-# ⛔️⛔️⛔️⛔️
-
-> [!CAUTION]
-> This library is an alpha version and should not be considered ready for production use while this message is visible.
-
-# ☝️☝️☝️☝️☝️☝️
-
 ## Install
 
 ```shell

packages/sdk/fastly/__tests__/api/EdgeFeatureStore.test.ts

@@ -1,7 +1,7 @@
 import { AsyncStoreFacade, LDFeatureStore } from '@launchdarkly/js-server-sdk-common';
 
 import { EdgeFeatureStore } from '../../src/api/EdgeFeatureStore';
-import mockEdgeProvider from '../../src/utils/mockEdgeProvider';
+import mockEdgeProvider from '../utils/mockEdgeProvider';
 import * as testData from './testData.json';
 
 describe('EdgeFeatureStore', () => {

packages/sdk/fastly/__tests__/index.test.ts

@@ -21,6 +21,7 @@ describe('init', () => {
   beforeAll(async () => {
     mockKVStore = new KVStore('test-kv-store') as jest.Mocked<KVStore>;
     const testDataString = JSON.stringify(testData);
+
     mockKVStore.get.mockResolvedValue({
       text: jest.fn().mockResolvedValue(testDataString),
       json: jest.fn().mockResolvedValue(testData),

packages/sdk/fastly/src/utils/mockEdgeProvider.ts → packages/sdk/fastly/__tests__/utils/mockEdgeProvider.ts

@@ -1,4 +1,4 @@
-import { EdgeProvider } from '../api';
+import { EdgeProvider } from '../../src/api';
 
 const mockEdgeProvider: EdgeProvider = {
   get: jest.fn(),

packages/sdk/fastly/__tests__/utils/validateOptions.test.ts

@@ -1,25 +1,25 @@
 import { BasicLogger } from '@launchdarkly/js-server-sdk-common';
 
-import mockFeatureStore from '../../src/utils/mockFeatureStore';
 import validateOptions from '../../src/utils/validateOptions';
+import mockFeatureStore from './mockFeatureStore';
 
 describe('validateOptions', () => {
   test('throws without SDK key', () => {
     expect(() => {
       validateOptions('', {});
-    }).toThrowError(/You must configure the client with a client key/);
+    }).toThrow(/You must configure the client with a client-side id/);
   });
 
   test('throws without featureStore', () => {
     expect(() => {
       validateOptions('test-sdk-key', {});
-    }).toThrowError(/You must configure the client with a feature store/);
+    }).toThrow(/You must configure the client with a feature store/);
   });
 
   test('throws without logger', () => {
     expect(() => {
       validateOptions('test-sdk-key', { featureStore: mockFeatureStore });
-    }).toThrowError(/You must configure the client with a logger/);
+    }).toThrow(/You must configure the client with a logger/);
   });
 
   test('success valid options', () => {

packages/sdk/fastly/example/src/index.ts

@@ -8,7 +8,7 @@ import { init } from '@launchdarkly/fastly-server-sdk';
 import type { LDMultiKindContext } from '@launchdarkly/js-server-sdk-common';
 
 // Set your LaunchDarkly client ID here
-const LAUNCHDARKLY_CLIENT_ID = '<your-client-id>';
+const LAUNCHDARKLY_CLIENT_ID = '675aea6b1b327709c85da941';
 // Set the KV store name used to store the LaunchDarkly data here
 const KV_STORE_NAME = 'launchdarkly';
 // Set the Fastly Backend name used to send LaunchDarkly events here
@@ -71,6 +71,32 @@ async function handleRequest(event: FetchEvent) {
 
   const url = new URL(req.url);
 
+  if (url.pathname === '/loop') {
+    const flagValues: boolean[] = [];
+
+    // Run evaluations in series instead of parallel
+    const runEvaluationsInSeries = async (
+      count: number,
+      results: boolean[],
+    ): Promise<boolean[]> => {
+      if (count <= 0) {
+        return results;
+      }
+
+      const result = await ldClient.boolVariation('example-flag', flagContext, false);
+      results.push(result);
+
+      return runEvaluationsInSeries(count - 1, results);
+    };
+
+    await runEvaluationsInSeries(35, flagValues);
+
+    return new Response(JSON.stringify(flagValues, undefined, 2), {
+      status: 200,
+      headers: new Headers({ 'Content-Type': 'application/json' }),
+    });
+  }
+
   if (url.pathname === '/') {
     const flagKey = 'example-flag';
     const variationDetail = await ldClient.boolVariationDetail(flagKey, flagContext, false);

packages/sdk/fastly/src/api/EdgeFeatureStore.ts

@@ -14,6 +14,7 @@ export interface EdgeProvider {
 
 export class EdgeFeatureStore implements LDFeatureStore {
   private readonly _rootKey: string;
+  private _kvData: string | null | undefined;
 
   constructor(
     private readonly _edgeProvider: EdgeProvider,
@@ -24,6 +25,18 @@ export class EdgeFeatureStore implements LDFeatureStore {
     this._rootKey = `LD-Env-${sdkKey}`;
   }
 
+  /**
+   * This function is used to lazy load the KV data from the edge provider. This is necessary because Fastly Compute
+   * has a limit of 32 backend requests (including requests to fetch the KV data).
+   * https://docs.fastly.com/products/compute-resource-limits
+   */
+  private async _getKVData(): Promise<string | null | undefined> {
+    if (!this._kvData) {
+      this._kvData = await this._edgeProvider.get(this._rootKey);
+    }
+    return this._kvData;
+  }
+
   async get(
     kind: DataKind,
     dataKey: string,
@@ -34,7 +47,7 @@ export class EdgeFeatureStore implements LDFeatureStore {
     this._logger.debug(`Requesting ${dataKey} from ${this._rootKey}.${kindKey}`);
 
     try {
-      const i = await this._edgeProvider.get(this._rootKey);
+      const i = await this._getKVData();
 
       if (!i) {
         throw new Error(`${this._rootKey}.${kindKey} is not found in KV.`);
@@ -66,7 +79,7 @@ export class EdgeFeatureStore implements LDFeatureStore {
     const kindKey = namespace === 'features' ? 'flags' : namespace;
     this._logger.debug(`Requesting all from ${this._rootKey}.${kindKey}`);
     try {
-      const i = await this._edgeProvider.get(this._rootKey);
+      const i = await this._getKVData();
       if (!i) {
         throw new Error(`${this._rootKey}.${kindKey} is not found in KV.`);
       }
@@ -93,7 +106,7 @@ export class EdgeFeatureStore implements LDFeatureStore {
   }
 
   async initialized(callback: (isInitialized: boolean) => void = noop): Promise<void> {
-    const config = await this._edgeProvider.get(this._rootKey);
+    const config = await this._getKVData();
     const result = config !== null;
     this._logger.debug(`Is ${this._rootKey} initialized? ${result}`);
     callback(result);

packages/sdk/fastly/src/utils/validateOptions.ts

@@ -1,4 +1,4 @@
-import { LDOptions as LDOptionsCommon } from '@launchdarkly/js-server-sdk-common';
+import { LDOptions as LDOptionsCommon, TypeValidators } from '@launchdarkly/js-server-sdk-common';
 
 /**
  * The Launchdarkly Fastly Compute SDK configuration options.
@@ -16,17 +16,23 @@ export type FastlySDKOptions = Pick<LDOptionsCommon, 'logger' | 'sendEvents' | '
  */
 export type LDOptionsInternal = FastlySDKOptions & Pick<LDOptionsCommon, 'featureStore'>;
 
-const validateOptions = (sdkKey: string, options: LDOptionsInternal) => {
+const validators = {
+  clientSideId: TypeValidators.String,
+  featureStore: TypeValidators.ObjectOrFactory,
+  logger: TypeValidators.Object,
+};
+
+const validateOptions = (clientSideId: string, options: LDOptionsInternal) => {
   const { eventsBackendName, featureStore, logger, sendEvents, ...rest } = options;
-  if (!sdkKey) {
-    throw new Error('You must configure the client with a client key');
+  if (!clientSideId || !validators.clientSideId.is(clientSideId)) {
+    throw new Error('You must configure the client with a client-side id');
   }
 
-  if (!featureStore || typeof featureStore !== 'object' || !featureStore.get) {
+  if (!featureStore || !validators.featureStore.is(featureStore)) {
     throw new Error('You must configure the client with a feature store');
   }
 
-  if (!logger) {
+  if (!logger || !validators.logger.is(logger)) {
     throw new Error('You must configure the client with a logger');
   }