[FSSDK-12009] configurable prediction endpoint (#1102)

Author: junaed-optimizely

lib/client_factory.ts

@@ -57,7 +57,8 @@ export const getOptimizelyInstance = (config: OptimizelyFactoryConfig): Optimize
     retryConfig: {
       maxRetries: DEFAULT_CMAB_RETRIES,
       backoffProvider: () => new ConstantBackoff(DEFAULT_CMAB_BACKOFF_MS),
-    }
+    },
+    predictionEndpointTemplate: config.cmab?.predictionEndpointTemplate,
   });
 
   const cmabCache: CacheWithRemove<CmabCacheValue> = config.cmab?.cache ?

lib/core/decision_service/cmab/cmab_client.spec.ts

@@ -354,4 +354,50 @@ describe('DefaultCmabClient', () => {
 
     await expect(cmabClient.fetchDecision(ruleId, userId, attributes, cmabUuid)).rejects.toThrow('error');
   });
+
+  it('should use custom prediction endpoint template when provided', async () => {
+    const requestHandler = getMockRequestHandler();
+
+    const mockMakeRequest: MockInstance<RequestHandler['makeRequest']> = requestHandler.makeRequest;
+    mockMakeRequest.mockReturnValue(getMockAbortableRequest(mockSuccessResponse('var456')));
+
+    const customEndpoint = 'https://custom.example.com/predict/%s';
+    const cmabClient = new DefaultCmabClient({
+      requestHandler,
+      predictionEndpointTemplate: customEndpoint,
+    });
+    const ruleId = '789';
+    const userId = 'user789';
+    const attributes = {
+      browser: 'firefox',
+    };
+    const cmabUuid = 'uuid789';
+    const variation = await cmabClient.fetchDecision(ruleId, userId, attributes, cmabUuid);
+    const [requestUrl] = mockMakeRequest.mock.calls[0];
+
+    expect(variation).toBe('var456');
+    expect(mockMakeRequest.mock.calls.length).toBe(1);
+    expect(requestUrl).toBe('https://custom.example.com/predict/789');
+  });
+
+  it('should use default prediction endpoint template when not provided', async () => {
+    const requestHandler = getMockRequestHandler();
+    const mockMakeRequest: MockInstance<RequestHandler['makeRequest']> = requestHandler.makeRequest;
+    mockMakeRequest.mockReturnValue(getMockAbortableRequest(mockSuccessResponse('var999')));
+    const cmabClient = new DefaultCmabClient({
+      requestHandler,
+    });
+    const ruleId = '555';
+    const userId = 'user555';
+    const attributes = {
+      browser: 'safari',
+    };
+    const cmabUuid = 'uuid555';
+    const variation = await cmabClient.fetchDecision(ruleId, userId, attributes, cmabUuid);
+    const [requestUrl] = mockMakeRequest.mock.calls[0];
+
+    expect(variation).toBe('var999');
+    expect(mockMakeRequest.mock.calls.length).toBe(1);
+    expect(requestUrl).toBe('https://prediction.cmab.optimizely.com/predict/555');
+  });
 });

lib/core/decision_service/cmab/cmab_client.ts

@@ -33,25 +33,30 @@ export interface CmabClient {
   ): Promise<string>
 }
 
-const CMAB_PREDICTION_ENDPOINT = 'https://prediction.cmab.optimizely.com/predict/%s';
+const DEFAULT_CMAB_PREDICTION_ENDPOINT = 'https://prediction.cmab.optimizely.com/predict/%s';
 
 export type RetryConfig = {
   maxRetries: number,
   backoffProvider?: Producer<BackoffController>;
 }
 
 export type CmabClientConfig = {
-  requestHandler: RequestHandler,
+  requestHandler: RequestHandler;
   retryConfig?: RetryConfig;
+  predictionEndpointTemplate?: string;
 }
 
 export class DefaultCmabClient implements CmabClient {
   private requestHandler: RequestHandler;
   private retryConfig?: RetryConfig;
+  private predictionEndpointTemplate: string = DEFAULT_CMAB_PREDICTION_ENDPOINT;
 
   constructor(config: CmabClientConfig) {
     this.requestHandler = config.requestHandler;
     this.retryConfig = config.retryConfig;
+    if (config.predictionEndpointTemplate) {
+      this.predictionEndpointTemplate = config.predictionEndpointTemplate;
+    }
   }
 
   async fetchDecision(
@@ -60,7 +65,7 @@ export class DefaultCmabClient implements CmabClient {
     attributes: UserAttributes,
     cmabUuid: string,
   ): Promise<string> {
-    const url = sprintf(CMAB_PREDICTION_ENDPOINT, ruleId);
+    const url = sprintf(this.predictionEndpointTemplate, ruleId);
 
     const cmabAttributes = Object.keys(attributes).map((key) => ({
       id: key,

lib/shared_types.ts

@@ -402,6 +402,7 @@ export interface Config {
     cacheSize?: number;
     cacheTtl?: number;
     cache?: CacheWithRemove<string>;
+    predictionEndpointTemplate?: string;
   }
 }