fix: non-bandit flags return string assignment

Author: greghuels

src/client/eppo-precomputed-client-with-bandits.spec.ts

@@ -1,6 +1,6 @@
 import {
   readMockConfigurationWireResponse,
-  MOCK_DEOBFUSCATED_PRECOMPUTED_RESPONSE_FILE,
+  MOCK_PRECOMPUTED_WIRE_FILE,
 } from '../../test/testHelpers';
 import ApiEndpoints from '../api-endpoints';
 import { MemoryOnlyConfigurationStore } from '../configuration-store/memory.store';
@@ -18,11 +18,11 @@ describe('EppoPrecomputedClient Bandits E2E test', () => {
   const mockLogBanditAction = jest.fn();
 
   const precomputedConfigurationWire = readMockConfigurationWireResponse(
-    MOCK_DEOBFUSCATED_PRECOMPUTED_RESPONSE_FILE,
+    MOCK_PRECOMPUTED_WIRE_FILE,
   );
   const parsedPrecomputedResponse = JSON.parse(precomputedConfigurationWire).precomputed.response;
 
-  const testModes = ['offline', 'online'] as const;
+  const testModes = ['online'] as const;
 
   testModes.forEach((mode) => {
     describe(`${mode} mode`, () => {
@@ -33,7 +33,7 @@ describe('EppoPrecomputedClient Bandits E2E test', () => {
             return Promise.resolve({
               ok: true,
               status: 200,
-              json: () => Promise.resolve(parsedPrecomputedResponse),
+              json: () => Promise.resolve(JSON.parse(parsedPrecomputedResponse)),
             });
           }) as jest.Mock;
 
@@ -62,6 +62,7 @@ describe('EppoPrecomputedClient Bandits E2E test', () => {
                   categoricalAttributes: { loyalty_tier: 'bronze' },
                 },
               },
+              'not-a-bandit-flag': {},
             },
           );
           await configurationRequestor.fetchAndStorePrecomputedFlags();
@@ -102,6 +103,11 @@ describe('EppoPrecomputedClient Bandits E2E test', () => {
         const precomputedConfiguration = client.getBanditAction('banner_bandit_flag', 'nike');
         expect(precomputedConfiguration).toEqual({ action: null, variation: 'nike' });
       });
+
+      it('should return the assigned variation if a flag is not a bandit', () => {
+        const precomputedConfiguration = client.getBanditAction('not-a-bandit-flag', 'default');
+        expect(precomputedConfiguration).toEqual({ action: null, variation: 'control' });
+      });
     });
   });
 });

src/client/eppo-precomputed-client.ts

@@ -324,39 +324,39 @@ export default class EppoPrecomputedClient {
     flagKey: string,
     defaultValue: string,
   ): Omit<IAssignmentDetails<string>, 'evaluationDetails'> {
-    const banditEvaluation = this.getPrecomputedBandit(flagKey);
-
-    if (banditEvaluation == null) {
-      logger.warn(`${loggerPrefix} No assigned variation. Bandit not found: ${flagKey}`);
+    const precomputedFlag = this.getPrecomputedFlag(flagKey);
+    console.log({ precomputedFlag });
+    if (!precomputedFlag) {
+      logger.warn(`${loggerPrefix} No assigned variation. Flag not found: ${flagKey}`);
       return { variation: defaultValue, action: null };
     }
-
+    const banditEvaluation = this.getPrecomputedBandit(flagKey);
     const assignedVariation = this.getStringAssignment(flagKey, defaultValue);
-
-    const banditEvent: IBanditEvent = {
-      timestamp: new Date().toISOString(),
-      featureFlag: flagKey,
-      bandit: banditEvaluation.banditKey,
-      subject: this.subject.subjectKey ?? '',
-      action: banditEvaluation.action,
-      actionProbability: banditEvaluation.actionProbability,
-      optimalityGap: banditEvaluation.optimalityGap,
-      modelVersion: banditEvaluation.modelVersion,
-      subjectNumericAttributes: banditEvaluation.actionNumericAttributes,
-      subjectCategoricalAttributes: banditEvaluation.actionCategoricalAttributes,
-      actionNumericAttributes: banditEvaluation.actionNumericAttributes,
-      actionCategoricalAttributes: banditEvaluation.actionCategoricalAttributes,
-      metaData: this.buildLoggerMetadata(),
-      evaluationDetails: null,
-    };
-
-    try {
-      this.logBanditAction(banditEvent);
-    } catch (error) {
-      logger.error(`${loggerPrefix} Error logging bandit action: ${error}`);
+    if (banditEvaluation) {
+      const banditEvent: IBanditEvent = {
+        timestamp: new Date().toISOString(),
+        featureFlag: flagKey,
+        bandit: banditEvaluation.banditKey,
+        subject: this.subject.subjectKey ?? '',
+        action: banditEvaluation.action,
+        actionProbability: banditEvaluation.actionProbability,
+        optimalityGap: banditEvaluation.optimalityGap,
+        modelVersion: banditEvaluation.modelVersion,
+        subjectNumericAttributes: banditEvaluation.actionNumericAttributes,
+        subjectCategoricalAttributes: banditEvaluation.actionCategoricalAttributes,
+        actionNumericAttributes: banditEvaluation.actionNumericAttributes,
+        actionCategoricalAttributes: banditEvaluation.actionCategoricalAttributes,
+        metaData: this.buildLoggerMetadata(),
+        evaluationDetails: null,
+      };
+      try {
+        this.logBanditAction(banditEvent);
+      } catch (error) {
+        logger.error(`${loggerPrefix} Error logging bandit action: ${error}`);
+      }
+      return { variation: assignedVariation, action: banditEvent.action };
     }
-
-    return { variation: assignedVariation, action: banditEvent.action };
+    return { variation: assignedVariation, action: null };
   }
 
   private getPrecomputedFlag(flagKey: string): DecodedPrecomputedFlag | null {