[FSSDK-9785] handle duplicate experiment keys with a warning (#535)

When duplicate experiment keys are found in a datafile, SDK returns a correct experimentMap in OptimizelyConfig: - the experimentMap will contain the experiment later in the datafile experiments list. - add a warning log about "Duplicate experiment keys found in datafile: {key-name}"

Author: jaeopt

core-api/src/main/java/com/optimizely/ab/optimizelyconfig/OptimizelyConfigService.java

@@ -1,5 +1,5 @@
 /****************************************************************************
- * Copyright 2020-2021, Optimizely, Inc. and contributors  *
+ * Copyright 2020-2021, 2023, Optimizely, Inc. and contributors *
  * *
  * Licensed under the Apache License, Version 2.0 (the "License"); *
  * you may not use this file except in compliance with the License. *
@@ -18,6 +18,8 @@
 import com.optimizely.ab.annotations.VisibleForTesting;
 import com.optimizely.ab.config.*;
 import com.optimizely.ab.config.audience.Audience;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.util.*;
 
@@ -31,6 +33,8 @@ public class OptimizelyConfigService {
  private Map<String, List<FeatureVariable>> featureIdToVariablesMap = new HashMap<>();
  private Map<String, OptimizelyExperiment> experimentMapByExperimentId = new HashMap<>();
 
+ private static final Logger logger = LoggerFactory.getLogger(OptimizelyConfigService.class);
+
  public OptimizelyConfigService(ProjectConfig projectConfig) {
  this.projectConfig = projectConfig;
  this.audiences = getAudiencesList(projectConfig.getTypedAudiences(), projectConfig.getAudiences());
@@ -125,6 +129,11 @@ Map<String, OptimizelyExperiment> getExperimentsMap() {
  experiment.serializeConditions(this.audiencesMap)
  );
 
+ if (featureExperimentMap.containsKey(experiment.getKey())) {
+ // continue with this warning, so the later experiment will be used.
+ logger.warn("Duplicate experiment keys found in datafile: {}", experiment.getKey());
+ }
+
  featureExperimentMap.put(experiment.getKey(), optimizelyExperiment);
  experimentMapByExperimentId.put(experiment.getId(), optimizelyExperiment);
  }

core-api/src/test/java/com/optimizely/ab/optimizelyconfig/OptimizelyConfigServiceTest.java

@@ -1,5 +1,5 @@
 /****************************************************************************
- * Copyright 2020-2021, Optimizely, Inc. and contributors  *
+ * Copyright 2020-2021, 2023, Optimizely, Inc. and contributors *
  * *
  * Licensed under the Apache License, Version 2.0 (the "License"); *
  * you may not use this file except in compliance with the License. *
@@ -15,23 +15,29 @@
  ***************************************************************************/
 package com.optimizely.ab.optimizelyconfig;
 
+import ch.qos.logback.classic.Level;
 import com.optimizely.ab.config.*;
 import com.optimizely.ab.config.audience.Audience;
+import com.optimizely.ab.internal.LogbackVerifier;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.mockito.runners.MockitoJUnitRunner;
 
 import java.util.*;
 import static java.util.Arrays.asList;
 import static org.junit.Assert.*;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 public class OptimizelyConfigServiceTest {
 
  private ProjectConfig projectConfig;
  private OptimizelyConfigService optimizelyConfigService;
  private OptimizelyConfig expectedConfig;
 
+ @Rule
+ public LogbackVerifier logbackVerifier = new LogbackVerifier();
+
  @Before
  public void initialize() {
  projectConfig = generateOptimizelyConfig();
@@ -46,6 +52,33 @@ public void testGetExperimentsMap() {
  assertEquals(expectedConfig.getExperimentsMap(), optimizelyExperimentMap);
  }
 
+ @Test
+ public void testGetExperimentsMapWithDuplicateKeys() {
+ List<Experiment> experiments = Arrays.asList(
+ new Experiment(
+ "first",
+ "duplicate_key",
+ null, null, Collections.<String>emptyList(), null,
+ Collections.<Variation>emptyList(), Collections.<String, String>emptyMap(), Collections.<TrafficAllocation>emptyList()
+ ),
+ new Experiment(
+ "second",
+ "duplicate_key",
+ null, null, Collections.<String>emptyList(), null,
+ Collections.<Variation>emptyList(), Collections.<String, String>emptyMap(), Collections.<TrafficAllocation>emptyList()
+ )
+ );
+
+ ProjectConfig projectConfig = mock(ProjectConfig.class);
+ OptimizelyConfigService optimizelyConfigService = new OptimizelyConfigService(projectConfig);
+ when(projectConfig.getExperiments()).thenReturn(experiments);
+
+ Map<String, OptimizelyExperiment> optimizelyExperimentMap = optimizelyConfigService.getExperimentsMap();
+ assertEquals("Duplicate keys should be overwritten", optimizelyExperimentMap.size(), 1);
+ assertEquals("Duplicate keys should be overwritten", optimizelyExperimentMap.get("duplicate_key").getId(), "second");
+ logbackVerifier.expectMessage(Level.WARN, "Duplicate experiment keys found in datafile: duplicate_key");
+ }
+
  @Test
  public void testRevision() {
  String revision = optimizelyConfigService.getConfig().getRevision();

java-quickstart/src/main/java/com/optimizely/Example.java

@@ -56,7 +56,7 @@ private void processVisitor(String userId, Map<String, Object> attributes) {
 
  public static void main(String[] args) throws InterruptedException {
  Optimizely optimizely = OptimizelyFactory.newDefaultInstance("BX9Y3bTa4YErpHZEMpAwHm");
-
+ 
  Example example = new Example(optimizely);
  Random random = new Random();