feat: support incremental configuration synchronization client

apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/config/BizConfig.java

@@ -240,6 +240,11 @@ public boolean isConfigServiceCacheKeyIgnoreCase() {
     return getBooleanProperty("config-service.cache.key.ignore-case", false);
   }
 
+  public boolean isConfigServiceChangeCacheEnabled() {
+    return getBooleanProperty("config-service.change.cache.enabled", false);
+  }
+
+
   int checkInt(int value, int min, int max, int defaultValue) {
     if (value >= min && value <= max) {
       return value;

apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/repository/ReleaseRepository.java

@@ -37,13 +37,15 @@ Release findFirstByAppIdAndClusterNameAndNamespaceNameAndIsAbandonedFalseOrderBy
 
   Release findByIdAndIsAbandonedFalse(long id);
 
+  Release findByReleaseKey(String releaseKey);
+
   List<Release> findByAppIdAndClusterNameAndNamespaceNameOrderByIdDesc(String appId, String clusterName, String namespaceName, Pageable page);
 
   List<Release> findByAppIdAndClusterNameAndNamespaceNameAndIsAbandonedFalseOrderByIdDesc(String appId, String clusterName, String namespaceName, Pageable page);
 
   List<Release> findByAppIdAndClusterNameAndNamespaceNameAndIsAbandonedFalseAndIdBetweenOrderByIdDesc(String appId, String clusterName, String namespaceName, long fromId, long toId);
 
-  List<Release> findByReleaseKeyIn(Set<String> releaseKey);
+  List<Release> findByReleaseKeyIn(Set<String> releaseKeys);
 
   List<Release> findByIdIn(Set<Long> releaseIds);
 

apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/service/ReleaseService.java

@@ -119,6 +119,10 @@ public List<Release> findByReleaseKeys(Set<String> releaseKeys) {
     return releaseRepository.findByReleaseKeyIn(releaseKeys);
   }
 
+  public Release findByReleaseKey(String releaseKey) {
+    return releaseRepository.findByReleaseKey(releaseKey);
+  }
+
   public Release findLatestActiveRelease(Namespace namespace) {
     return findLatestActiveRelease(namespace.getAppId(),
                                    namespace.getClusterName(), namespace.getNamespaceName());

apollo-configservice/src/main/java/com/ctrip/framework/apollo/configservice/ConfigServiceAutoConfiguration.java

@@ -30,6 +30,7 @@
 import com.ctrip.framework.apollo.configservice.service.ReleaseMessageServiceWithCache;
 import com.ctrip.framework.apollo.configservice.service.config.ConfigService;
 import com.ctrip.framework.apollo.configservice.service.config.ConfigServiceWithCache;
+import com.ctrip.framework.apollo.configservice.service.config.ConfigServiceWithChangeCache;
 import com.ctrip.framework.apollo.configservice.service.config.DefaultConfigService;
 import com.ctrip.framework.apollo.configservice.util.AccessKeyUtil;
 import io.micrometer.core.instrument.MeterRegistry;
@@ -73,9 +74,12 @@ public ConfigService configService() {
       return new ConfigServiceWithCache(releaseService, releaseMessageService,
           grayReleaseRulesHolder(), bizConfig, meterRegistry);
     }
+    if(bizConfig.isConfigServiceChangeCacheEnabled()){
+      return new ConfigServiceWithChangeCache(releaseService, releaseMessageService,
+		      grayReleaseRulesHolder(), bizConfig, meterRegistry);
+    }
     return new DefaultConfigService(releaseService, grayReleaseRulesHolder());
   }
-
   @Bean
   public static NoOpPasswordEncoder passwordEncoder() {
     return (NoOpPasswordEncoder) NoOpPasswordEncoder.getInstance();

apollo-configservice/src/main/java/com/ctrip/framework/apollo/configservice/controller/ConfigController.java

@@ -16,6 +16,7 @@
  */
 package com.ctrip.framework.apollo.configservice.controller;
 
+import com.ctrip.framework.apollo.biz.config.BizConfig;
 import com.ctrip.framework.apollo.biz.entity.Release;
 import com.ctrip.framework.apollo.common.entity.AppNamespace;
 import com.ctrip.framework.apollo.common.utils.WebUtils;
@@ -26,10 +27,13 @@
 import com.ctrip.framework.apollo.core.ConfigConsts;
 import com.ctrip.framework.apollo.core.dto.ApolloConfig;
 import com.ctrip.framework.apollo.core.dto.ApolloNotificationMessages;
+import com.ctrip.framework.apollo.core.dto.ConfigurationChange;
+import com.ctrip.framework.apollo.core.enums.ConfigSyncType;
 import com.ctrip.framework.apollo.tracer.Tracer;
 import com.google.common.base.Strings;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
 import com.google.gson.Gson;
 import com.google.gson.reflect.TypeToken;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -42,6 +46,9 @@
 import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
 import java.lang.reflect.Type;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -59,21 +66,25 @@ public class ConfigController {
   private final NamespaceUtil namespaceUtil;
   private final InstanceConfigAuditUtil instanceConfigAuditUtil;
   private final Gson gson;
+  private final BizConfig bizConfig;
+
 
   private static final Type configurationTypeReference = new TypeToken<Map<String, String>>() {
-      }.getType();
+  }.getType();
 
   public ConfigController(
       final ConfigService configService,
       final AppNamespaceServiceWithCache appNamespaceService,
       final NamespaceUtil namespaceUtil,
       final InstanceConfigAuditUtil instanceConfigAuditUtil,
-      final Gson gson) {
+      final Gson gson,
+      final BizConfig bizConfig) {
     this.configService = configService;
     this.appNamespaceService = appNamespaceService;
     this.namespaceUtil = namespaceUtil;
     this.instanceConfigAuditUtil = instanceConfigAuditUtil;
     this.gson = gson;
+    this.bizConfig = bizConfig;
   }
 
   @GetMapping(value = "/{appId}/{clusterName}/{namespace:.+}")
@@ -132,10 +143,10 @@ public ApolloConfig queryConfig(@PathVariable String appId, @PathVariable String
 
     auditReleases(appId, clusterName, dataCenter, clientIp, releases);
 
-    String mergedReleaseKey = releases.stream().map(Release::getReleaseKey)
-            .collect(Collectors.joining(ConfigConsts.CLUSTER_NAMESPACE_SEPARATOR));
+    String latestMergedReleaseKey = releases.stream().map(Release::getReleaseKey)
+        .collect(Collectors.joining(ConfigConsts.CLUSTER_NAMESPACE_SEPARATOR));
 
-    if (mergedReleaseKey.equals(clientSideReleaseKey)) {
+    if (latestMergedReleaseKey.equals(clientSideReleaseKey)) {
       // Client side configuration is the same with server side, return 304
       response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
       Tracer.logEvent("Apollo.Config.NotModified",
@@ -144,8 +155,42 @@ public ApolloConfig queryConfig(@PathVariable String appId, @PathVariable String
     }
 
     ApolloConfig apolloConfig = new ApolloConfig(appId, appClusterNameLoaded, originalNamespace,
-        mergedReleaseKey);
-    apolloConfig.setConfigurations(mergeReleaseConfigurations(releases));
+        latestMergedReleaseKey);
+
+    Map<String, String> latestConfigurations = mergeReleaseConfigurations(releases);
+
+    if (bizConfig.isConfigServiceChangeCacheEnabled()) {
+      LinkedHashSet<String> clientSideReleaseKeys = Sets.newLinkedHashSet(
+          Arrays.stream(clientSideReleaseKey.split("\\+")).collect(Collectors.toList()));
+
+      Map<String, Release> historyReleases = configService.findReleasesByReleaseKeys(
+          clientSideReleaseKeys);
+      //find history releases
+      if (historyReleases != null) {
+        //order by clientSideReleaseKeys
+        List<Release> historyReleasesWithOrder = new ArrayList<>();
+        for (String item : clientSideReleaseKeys) {
+          Release release = historyReleases.get(item);
+          if (release != null) {
+            historyReleasesWithOrder.add(release);
+          }
+        }
+
+        Map<String, String> historyConfigurations = mergeReleaseConfigurations
+            (historyReleasesWithOrder);
+
+        List<ConfigurationChange> configurationChanges = configService.calcConfigurationChanges(
+            latestConfigurations, historyConfigurations);
+
+        apolloConfig.setConfigurationChanges(configurationChanges);
+
+        apolloConfig.setConfigSyncType(ConfigSyncType.INCREMENTALSYNC.getValue());
+        return apolloConfig;
+      }
+
+    }
+
+    apolloConfig.setConfigurations(latestConfigurations);
 
     Tracer.logEvent("Apollo.Config.Found", assembleKey(appId, appClusterNameLoaded,
         originalNamespace, dataCenter));

apollo-configservice/src/main/java/com/ctrip/framework/apollo/configservice/service/config/AbstractConfigService.java

@@ -21,9 +21,16 @@
 import com.ctrip.framework.apollo.core.ConfigConsts;
 import com.ctrip.framework.apollo.core.dto.ApolloNotificationMessages;
 
+import com.ctrip.framework.apollo.core.dto.ConfigurationChange;
 import com.google.common.base.Strings;
 
+import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
 
 /**
  * @author Jason Song([email protected])
@@ -93,6 +100,52 @@ private Release findRelease(String clientAppId, String clientIp, String clientLa
     return release;
   }
 
+  public List<ConfigurationChange> calcConfigurationChanges(
+      Map<String, String> latestReleaseConfigurations, Map<String, String> historyConfigurations) {
+    if (latestReleaseConfigurations == null) {
+      latestReleaseConfigurations = new HashMap<>();
+    }
+
+    if (historyConfigurations == null) {
+      historyConfigurations = new HashMap<>();
+    }
+
+    Set<String> previousKeys = historyConfigurations.keySet();
+    Set<String> currentKeys = latestReleaseConfigurations.keySet();
+
+    Set<String> commonKeys = Sets.intersection(previousKeys, currentKeys);
+    Set<String> newKeys = Sets.difference(currentKeys, commonKeys);
+    Set<String> removedKeys = Sets.difference(previousKeys, commonKeys);
+
+    List<ConfigurationChange> changes = Lists.newArrayList();
+
+    for (String newKey : newKeys) {
+      changes.add(new ConfigurationChange(newKey, latestReleaseConfigurations.get(newKey),
+          "ADDED"));
+    }
+
+    for (String removedKey : removedKeys) {
+      changes.add(new ConfigurationChange(removedKey, null, "DELETED"));
+    }
+
+    for (String commonKey : commonKeys) {
+      String previousValue = historyConfigurations.get(commonKey);
+      String currentValue = latestReleaseConfigurations.get(commonKey);
+      if (com.google.common.base.Objects.equal(previousValue, currentValue)) {
+        continue;
+      }
+      changes.add(
+          new ConfigurationChange(commonKey, currentValue, "MODIFIED"));
+    }
+
+    return changes;
+  }
+
+  @Override
+  public Map<String, Release> findReleasesByReleaseKeys(Set<String> releaseKeys) {
+    return null;
+  }
+
   /**
    * Find active release by id
    */

apollo-configservice/src/main/java/com/ctrip/framework/apollo/configservice/service/config/ConfigService.java

@@ -23,7 +23,7 @@
 /**
  * @author Jason Song([email protected])
  */
-public interface ConfigService extends ReleaseMessageListener {
+public interface ConfigService extends ReleaseMessageListener, IncrementalSyncConfigService {
 
   /**
    * Load config

apollo-configservice/src/main/java/com/ctrip/framework/apollo/configservice/service/config/ConfigServiceWithCache.java

@@ -62,9 +62,9 @@ public class ConfigServiceWithCache extends AbstractConfigService {
   private static final String TRACER_EVENT_CACHE_GET = "ConfigCache.Get";
   private static final String TRACER_EVENT_CACHE_GET_ID = "ConfigCache.GetById";
 
-  private final ReleaseService releaseService;
+  protected final ReleaseService releaseService;
   private final ReleaseMessageService releaseMessageService;
-  private final BizConfig bizConfig;
+  protected final BizConfig bizConfig;
   private final MeterRegistry meterRegistry;
 
   private LoadingCache<String, ConfigCacheEntry> configCache;