feat(utils): add indexer endpoint env var support to AppConfigService (#261)

Add support for VITE_APP_CFG_INDEXER_ENDPOINT_{NETWORK_ID} environment
variables to configure indexer endpoints at runtime.

Changes:
- Add parsing for VITE_APP_CFG_INDEXER_ENDPOINT_* pattern in loadFromViteEnvironment
- Add merging of loaded indexer endpoints into config.indexerEndpoints
- Add unit tests for env var parsing and getIndexerEndpointOverride getter
- Update "getters warn before initialization" test to include indexer endpoint

This enables configuring indexer endpoints (which may contain API keys)
via .env.local files instead of committing secrets to app.config.json.

Author: pasevin

packages/utils/src/AppConfigService.ts

@@ -72,6 +72,7 @@ export class AppConfigService {
     const loadedNetworkServiceConfigs: NetworkServiceConfigs = {};
     const loadedGlobalServiceConfigs: GlobalServiceConfigs = {};
     const loadedRpcEndpoints: NetworkSpecificRpcEndpoints = {};
+    const loadedIndexerEndpoints: Record<string, string> = {};
     const loadedFeatureFlags: FeatureFlags = {};
 
     for (const key in env) {
@@ -134,6 +135,13 @@ export class AppConfigService {
             loadedRpcEndpoints[networkId] = value;
             logger.debug(LOG_SYSTEM, `Loaded RPC override for ${networkId}: ${value}`);
           }
+        } else if (key.startsWith(`${VITE_ENV_PREFIX}INDEXER_ENDPOINT_`)) {
+          const networkIdSuffix = key.substring(`${VITE_ENV_PREFIX}INDEXER_ENDPOINT_`.length);
+          const networkId = networkIdSuffix.toLowerCase().replace(/_/g, '-');
+          if (networkId) {
+            loadedIndexerEndpoints[networkId] = value;
+            logger.debug(LOG_SYSTEM, `Loaded indexer endpoint for ${networkId}: ${value}`);
+          }
         } else if (key.startsWith(`${VITE_ENV_PREFIX}FEATURE_FLAG_`)) {
           const flagNameSuffix = key.substring(`${VITE_ENV_PREFIX}FEATURE_FLAG_`.length);
           const flagName = flagNameSuffix.toLowerCase();
@@ -167,6 +175,14 @@ export class AppConfigService {
         }
       }
     }
+    if (Object.keys(loadedIndexerEndpoints).length > 0) {
+      if (!this.config.indexerEndpoints) this.config.indexerEndpoints = {};
+      for (const networkKey in loadedIndexerEndpoints) {
+        if (Object.prototype.hasOwnProperty.call(loadedIndexerEndpoints, networkKey)) {
+          this.config.indexerEndpoints[networkKey] = loadedIndexerEndpoints[networkKey];
+        }
+      }
+    }
     this.config.featureFlags = { ...this.config.featureFlags, ...loadedFeatureFlags };
 
     logger.info(

packages/utils/src/__tests__/AppConfigService.test.ts

@@ -92,6 +92,23 @@ describe('AppConfigService', () => {
       expect(config.rpcEndpoints?.['polygon-mainnet']).toBe('https://polygon.customrpc.com');
     });
 
+    it('should parse VITE_APP_CFG_INDEXER_ENDPOINT_ variables correctly', async () => {
+      mockViteEnv['VITE_APP_CFG_INDEXER_ENDPOINT_STELLAR_TESTNET'] =
+        'https://indexer.stellar-testnet.com?apikey=test123';
+      mockViteEnv['VITE_APP_CFG_INDEXER_ENDPOINT_STELLAR_MAINNET'] =
+        'https://indexer.stellar-mainnet.com?apikey=prod456';
+
+      await appConfigServiceInstance.initialize([{ type: 'viteEnv', env: mockViteEnv }]);
+      const config = appConfigServiceInstance.getConfig();
+
+      expect(config.indexerEndpoints?.['stellar-testnet']).toBe(
+        'https://indexer.stellar-testnet.com?apikey=test123'
+      );
+      expect(config.indexerEndpoints?.['stellar-mainnet']).toBe(
+        'https://indexer.stellar-mainnet.com?apikey=prod456'
+      );
+    });
+
     it('should parse VITE_APP_CFG_FEATURE_FLAG_ variables correctly', async () => {
       mockViteEnv['VITE_APP_CFG_FEATURE_FLAG_SHOW_COOL_THING'] = 'true';
       mockViteEnv['VITE_APP_CFG_FEATURE_FLAG_HIDE_OLD_THING'] = 'false';
@@ -536,6 +553,27 @@ describe('AppConfigService', () => {
       ).toBeUndefined();
     });
 
+    it('getIndexerEndpointOverride should return correct indexer URL', async () => {
+      // Re-initialize with indexer endpoint
+      appConfigServiceInstance = new AppConfigService();
+      await appConfigServiceInstance.initialize([
+        {
+          type: 'viteEnv',
+          env: {
+            VITE_APP_CFG_INDEXER_ENDPOINT_STELLAR_TESTNET:
+              'https://indexer.stellar.com?apikey=test',
+          },
+        },
+      ]);
+
+      expect(appConfigServiceInstance.getIndexerEndpointOverride('stellar-testnet')).toBe(
+        'https://indexer.stellar.com?apikey=test'
+      );
+      expect(
+        appConfigServiceInstance.getIndexerEndpointOverride('non-existent-network')
+      ).toBeUndefined();
+    });
+
     it('getTypedNestedConfig should return typed nested configuration', async () => {
       // Setup a configuration with nested objects
       const jsonConfig = {
@@ -664,13 +702,19 @@ describe('AppConfigService', () => {
         'getRpcEndpointOverride called before initialization.'
       );
 
+      freshInstance.getIndexerEndpointOverride('test');
+      expect(logger.warn).toHaveBeenCalledWith(
+        'AppConfigService',
+        'getIndexerEndpointOverride called before initialization.'
+      );
+
       freshInstance.getTypedNestedConfig('test', 'config');
       expect(logger.warn).toHaveBeenCalledWith(
         'AppConfigService',
         'getTypedNestedConfig called before initialization.'
       );
 
-      expect(logger.warn).toHaveBeenCalledTimes(5);
+      expect(logger.warn).toHaveBeenCalledTimes(6);
     });
   });