NONE: add launchdarkly feature flagging support (#258)

* Add launchdarkly client

* update eslint plugin

* minor fixes

Author: Isaiah-Turner

package-lock.json

@@ -40,6 +40,7 @@
 		"core-js": "^3.36.0",
 		"dd-trace": "^4.17.0",
 		"express": "^4.18.2",
+		"launchdarkly-node-server-sdk": "^7.0.4",
 		"pino": "^8.15.0",
 		"pino-http": "^8.4.0",
 		"prisma": "^5.1.1",
@@ -55,7 +56,7 @@
 		"@types/supertest": "^2.0.12",
 		"@types/uuid": "^9.0.2",
 		"@typescript-eslint/eslint-plugin": "^6.4.0",
-		"@typescript-eslint/parser": "^6.4.0",
+		"@typescript-eslint/parser": "^6.21.0",
 		"commander": "^11.1.0",
 		"dotenv": "^16.3.1",
 		"dotenv-cli": "^7.3.0",

package.json

@@ -20,6 +20,7 @@ export type Config = {
 		readonly domain: string;
 		readonly webBaseUrl: URL;
 		readonly apiBaseUrl: URL;
+		readonly clusterName: string;
 		readonly oauth2: {
 			readonly authorizationServerBaseUrl: URL;
 			readonly clientId: string;
@@ -57,6 +58,7 @@ export const getConfig = (): Config => {
 				domain: readEnvVarString('FIGMA_DOMAIN', 'figma.com'),
 				webBaseUrl: new URL(readEnvVarString('FIGMA_WEB_BASE_URL')),
 				apiBaseUrl: new URL(readEnvVarString('FIGMA_API_BASE_URL')),
+				clusterName: readEnvVarString('CLUSTER_NAME', 'unknown'),
 				oauth2: {
 					authorizationServerBaseUrl: new URL(
 						readEnvVarString('FIGMA_OAUTH2_AUTHORIZATION_SERVER_BASE_URL'),

src/config/config.ts

@@ -0,0 +1,86 @@
+import type { LDClient, LDOptions } from 'launchdarkly-node-server-sdk';
+import { init } from 'launchdarkly-node-server-sdk';
+
+import { getLogger } from '../infrastructure';
+
+import { getConfig } from '.';
+
+export async function getLDClient(): Promise<LDClient | null> {
+	const ldSecretKey = getLaunchDarklySecretKey();
+
+	if (!ldSecretKey) {
+		getLogger().error(`No LaunchDarkly secret available.`);
+		return null;
+	}
+
+	const options: LDOptions = {
+		logger: {
+			error: (message) => getLogger().error(message),
+			warn: (message) => getLogger().warn(message),
+			info: () => {},
+			debug: () => {},
+		},
+	};
+	const client = init(ldSecretKey, options);
+	await client.waitForInitialization();
+	return client;
+}
+
+export async function getFeatureFlag<T>(
+	client: LDClient | null,
+	flag: string,
+	defaultValue: T,
+): Promise<T> {
+	if (!client) {
+		getLogger().error(
+			`No LaunchDarkly client provided, using default value for flag ${flag}: ${JSON.stringify(
+				defaultValue,
+			)}`,
+		);
+		return defaultValue;
+	}
+
+	const featureFlag = (await client.variation(
+		flag,
+		{ key: 'figma-for-jira' },
+		defaultValue,
+	)) as T;
+	return featureFlag;
+}
+
+function getLaunchDarklySecretKey(): string | undefined {
+	const env = getConfig().figma.clusterName;
+
+	let secretKey: string | undefined = undefined;
+
+	switch (env) {
+		case 'gov':
+		case 'production':
+		case 'staging':
+			secretKey = process.env['LAUNCH_DARKLY_SECRET_KEY'];
+			break;
+
+		default: {
+			const rawMap = process.env['LAUNCH_DARKLY_SECRET_KEY_MAP'];
+			if (!rawMap) {
+				secretKey = undefined;
+			} else {
+				const map = JSON.parse(rawMap) as unknown;
+				if (map && typeof map === 'object' && env in map) {
+					const value = map[env] as unknown;
+					if (typeof value === 'string') {
+						secretKey = value;
+					}
+				}
+			}
+		}
+	}
+
+	if (secretKey === undefined) {
+		getLogger().error('LaunchDarkly secret is undefined');
+	} else {
+		getLogger().info('LaunchDarkly secret is defined');
+	}
+
+	return secretKey;
+}