add getter for all target state

helix-gateway/src/main/java/org/apache/helix/gateway/api/constant/gatewayServiceManagerConstant.java

@@ -0,0 +1,6 @@
+package org.apache.helix.gateway.api.constant;
+
+public class gatewayServiceManagerConstant {
+  public static final String TARGET_STATE_ASSIGNMENT_KEY_NAME = "Assignment";
+  public static final String TIMESTAMP_KEY = "Timestamp";
+}

helix-gateway/src/main/java/org/apache/helix/gateway/service/GatewayServiceManager.java

@@ -19,6 +19,7 @@
  * under the License.
  */
 
+import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.google.common.collect.ImmutableSet;
@@ -36,6 +37,11 @@
 import org.apache.helix.gateway.participant.HelixGatewayParticipant;
 import org.apache.helix.gateway.util.GatewayCurrentStateCache;
 import org.apache.helix.gateway.util.PerKeyBlockingExecutor;
+import org.apache.helix.gateway.util.PollChannelUtil;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static org.apache.helix.gateway.api.constant.gatewayServiceManagerConstant.*;
 
 
 /**
@@ -46,6 +52,7 @@
  *  4. For ST reply message, update the tracker
  */
 public class GatewayServiceManager {
+  private static final Logger logger = LoggerFactory.getLogger(GatewayServiceManager.class);
   private static final ObjectMapper objectMapper = new ObjectMapper();
   public static final int CONNECTION_EVENT_THREAD_POOL_SIZE = 10;
   public static final ImmutableSet<String> SUPPORTED_MULTI_STATE_MODEL_TYPES =
@@ -128,12 +135,14 @@ public void updateCurrentState(String clusterName, String instanceName, String r
 
   public synchronized String serializeTargetState() {
     ObjectNode targetStateNode = new ObjectMapper().createObjectNode();
+    ObjectNode res = new ObjectMapper().createObjectNode();
     for (String clusterName : _currentStateCacheMap.keySet()) {
       // add the json node to the target state node
       targetStateNode.set(clusterName, getOrCreateCache(clusterName).serializeTargetAssignmentsToJSONNode());
     }
-    targetStateNode.set("timestamp", objectMapper.valueToTree(System.currentTimeMillis()));
-    return targetStateNode.toString();
+    res.set(TARGET_STATE_ASSIGNMENT_KEY_NAME, targetStateNode);
+    res.set(TIMESTAMP_KEY, objectMapper.valueToTree(System.currentTimeMillis()));
+    return res.toString();
   }
 
   public void updateTargetState(String clusterName, String instanceName, String resourceId, String shardId,
@@ -162,7 +171,7 @@ private ShardStateUpdator(GatewayServiceEvent event) {
 
     @Override
     public void run() {
-      System.out.println("Processing state transition result " + _event.getInstanceName());
+      logger.info("Processing state transition result " + _event.getInstanceName());
       HelixGatewayParticipant participant =
           getHelixGatewayParticipant(_event.getClusterName(), _event.getInstanceName());
       if (participant == null) {

helix-gateway/src/main/java/org/apache/helix/gateway/util/GatewayCurrentStateCache.java

@@ -21,6 +21,7 @@
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.google.common.collect.ImmutableMap;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
@@ -59,6 +60,14 @@ public String getTargetState(String instance, String resource, String shard) {
     return shardStateMap == null ? null : shardStateMap.getState(resource, shard);
   }
 
+  public synchronized Map<String, Map<String, Map<String, String>>> getAllTargetStates() {
+    Map<String, Map<String, Map<String, String>>> result = new HashMap<>();
+    for (Map.Entry<String, ShardStateMap> entry : _targetStateMap.entrySet()) {
+      result.put(entry.getKey(), new HashMap<>(entry.getValue()._stateMap));
+    }
+    return result;
+  }
+
   /**
    * Update the cached current state of instances in a cluster, and return the diff of the change.
    * @param userCurrentStateMap The new current state map of instances in the cluster
@@ -141,8 +150,8 @@ public synchronized void resetTargetStateCache(String instance) {
   }
 
   public static class ShardStateMap {
+    // resource -> shard -> state
     Map<String, Map<String, String>> _stateMap;
-    ObjectNode root = mapper.createObjectNode();
 
     public ShardStateMap(Map<String, Map<String, String>> stateMap) {
       _stateMap = new HashMap<>(stateMap);

helix-gateway/src/main/java/org/apache/helix/gateway/util/PollChannelUtil.java

@@ -128,4 +128,20 @@ public long getLastUpdatedTime(){
       return _lastUpdatedTime;
     }
   }
+
+  /**
+   * Target assignments representation as JSON
+   */
+  public static class TargetAssignment {
+    // cluster -> instance -> resource -> shard -> state
+    @JsonProperty ("Assignment")
+    String _targetAssignment;
+    @JsonProperty ("Timestamp")
+    long _timestamp;
+
+    public TargetAssignment(String targetAssignment, long timestamp){
+      _targetAssignment = targetAssignment;
+      _timestamp = timestamp;
+    }
+  }
 }

helix-gateway/src/test/java/org/apache/helix/gateway/integration/TestFilePullChannelE2E.java

@@ -228,7 +228,7 @@ private void verifyTargetState() throws Exception {
       int finalI = i;
       Assert.assertTrue(TestHelper.verify(() -> {
         String content = Files.readString(targetPaths.get(finalI));
-        return content.contains("{\"TestDB\":{\"TestDB_0\":\"ONLINE\"}}}");
+        return content.contains("{\"TestDB\":{\"TestDB_0\":\"ONLINE\"}}");
       }, TestHelper.WAIT_DURATION));
     }
   }