[FSSDK-12039] update: Fix reasons and logging in CMAB decision process (#590)

Author: FarhanAnjum-opti

core-api/src/main/java/com/optimizely/ab/Optimizely.java

@@ -1494,14 +1494,15 @@ private Map<String, OptimizelyDecision> decideForKeysInternal(@Nonnull Optimizel
         for (int i = 0; i < flagsWithoutForcedDecision.size(); i++) {
             DecisionResponse<FeatureDecision> decision = decisionList.get(i);
             boolean error = decision.isError();
+            List<String> reasons = decision.getReasons().toReport();
             String experimentKey = null;
             if (decision.getResult() != null && decision.getResult().experiment != null) {
                 experimentKey = decision.getResult().experiment.getKey();
             }
             String flagKey = flagsWithoutForcedDecision.get(i).getKey();
 
             if (error) {
-                OptimizelyDecision optimizelyDecision = OptimizelyDecision.newErrorDecision(flagKey, user, DecisionMessage.CMAB_ERROR.reason(experimentKey));
+                OptimizelyDecision optimizelyDecision = OptimizelyDecision.newErrorDecision(flagKey, user, reasons);
                 decisionMap.put(flagKey, optimizelyDecision);
                 if (validKeys.contains(flagKey)) {
                     validKeys.remove(flagKey);

core-api/src/main/java/com/optimizely/ab/bucketing/DecisionService.java

@@ -957,11 +957,12 @@ private DecisionResponse<CmabDecision> getDecisionForCmabExperiment(@Nonnull Pro
         // User is in CMAB allocation, proceed to CMAB decision
         try {
             CmabDecision cmabDecision = cmabService.getDecision(projectConfig, userContext, experiment.getId(), options);
-
+            String message = String.format("Successfully fetched CMAB decision %s for experiment %s.", cmabDecision.toString(), experiment.getKey());
+            reasons.addInfo(message);
             return new DecisionResponse<>(cmabDecision, reasons);
         } catch (Exception e) {
-            String errorMessage = String.format("CMAB fetch failed for experiment \"%s\"", experiment.getKey());
-            reasons.addInfo(errorMessage);
+            String errorMessage = String.format("Failed to fetch CMAB data for experiment %s.", experiment.getKey());
+            reasons.addError(errorMessage);
             logger.error("{} {}", errorMessage, e.getMessage());
 
             return new DecisionResponse<>(null, reasons, true, null);

core-api/src/main/java/com/optimizely/ab/optimizelydecision/OptimizelyDecision.java

@@ -130,7 +130,20 @@ public static OptimizelyDecision newErrorDecision(@Nonnull String key,
             user,
             Arrays.asList(error));
     }
-    
+
+    public static OptimizelyDecision newErrorDecision(@Nonnull String key,
+                                                      @Nonnull OptimizelyUserContext user,
+                                                      @Nonnull List<String> reasons) {
+        return new OptimizelyDecision(
+            null,
+            false,
+            new OptimizelyJSON(Collections.emptyMap()),
+            null,
+            key,
+            user,
+            reasons);
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (obj == null || getClass() != obj.getClass()) return false;

core-api/src/test/java/com/optimizely/ab/OptimizelyTest.java

@@ -5090,7 +5090,6 @@ public void identifyUser() {
     @Test
     public void testDecideReturnsErrorDecisionWhenDecisionServiceFails() throws Exception {
         assumeTrue(datafileVersion >= Integer.parseInt(ProjectConfig.Version.V4.toString()));
-        
         // Use the CMAB datafile
         Optimizely optimizely = Optimizely.builder()
             .withDatafile(validConfigJsonCMAB())  
@@ -5099,6 +5098,7 @@ public void testDecideReturnsErrorDecisionWhenDecisionServiceFails() throws Exce
 
         // Mock decision service to return an error from CMAB
         DecisionReasons reasons = new DefaultDecisionReasons();
+        reasons.addError("Failed to fetch CMAB data for experiment exp-cmab.");
         FeatureDecision errorFeatureDecision = new FeatureDecision(new Experiment("123", "exp-cmab", "123"), null, FeatureDecision.DecisionSource.ROLLOUT);
         DecisionResponse<FeatureDecision> errorDecisionResponse = new DecisionResponse<>(
             errorFeatureDecision,
@@ -5129,7 +5129,6 @@ public void testDecideReturnsErrorDecisionWhenDecisionServiceFails() throws Exce
         OptimizelyUserContext userContext = optimizely.createUserContext("test_user");
         OptimizelyDecision decision = userContext.decide("feature_1"); // This is the feature flag key from cmab-config.json
 
-        System.out.println("reasons: " + decision.getReasons());
         // Verify the decision contains the error information
         assertFalse(decision.getEnabled());
         assertNull(decision.getVariationKey());

core-httpclient-impl/src/main/java/com/optimizely/ab/cmab/DefaultCmabClient.java

@@ -101,6 +101,7 @@ private String doFetch(String url, String requestBody) {
         request.setHeader("content-type", "application/json");
         CloseableHttpResponse response = null;
         try {
+            logger.info("Fetching CMAB decision: {} with body: {}", url, requestBody);
             response = httpClient.execute(request);
 
             if (!CmabClientHelper.isSuccessStatusCode(response.getStatusLine().getStatusCode())) {