BaseGatewayShardAllocator changes for Assigning the batch of shards

server/src/main/java/org/opensearch/gateway/BaseGatewayShardAllocator.java

@@ -36,6 +36,7 @@
 import org.apache.logging.log4j.Logger;
 import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.cluster.routing.RoutingNode;
+import org.opensearch.cluster.routing.RoutingNodes;
 import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.routing.allocation.AllocateUnassignedDecision;
 import org.opensearch.cluster.routing.allocation.AllocationDecision;
@@ -46,6 +47,8 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
+import java.util.concurrent.ConcurrentMap;
 
 /**
  * An abstract class that implements basic functionality for allocating
@@ -74,7 +77,26 @@ public void allocateUnassigned(
         ExistingShardsAllocator.UnassignedAllocationHandler unassignedAllocationHandler
     ) {
         final AllocateUnassignedDecision allocateUnassignedDecision = makeAllocationDecision(shardRouting, allocation, logger);
+        executeDecision(shardRouting, allocateUnassignedDecision, allocation, unassignedAllocationHandler);
+    }
+
+    public void allocateUnassignedBatch(Set<ShardRouting> shards, RoutingAllocation allocation) {
+        // make Allocation Decisions for all shards
+        ConcurrentMap<ShardRouting, AllocateUnassignedDecision> decisionMap = makeAllocationDecision(shards, allocation, logger);
+        // get all unassigned shards
+        RoutingNodes.UnassignedShards.UnassignedIterator iterator = allocation.routingNodes().unassigned().iterator();
+        while (iterator.hasNext()){
+            ShardRouting shard = iterator.next();
+            if (shards.contains(shard)) {
+                executeDecision(shard, decisionMap.get(shard), allocation, iterator);
+            }
+        }
+    }
 
+    private void executeDecision(ShardRouting shardRouting,
+                                 AllocateUnassignedDecision allocateUnassignedDecision,
+                                 RoutingAllocation allocation,
+                                 ExistingShardsAllocator.UnassignedAllocationHandler unassignedAllocationHandler) {
         if (allocateUnassignedDecision.isDecisionTaken() == false) {
             // no decision was taken by this allocator
             return;
@@ -91,7 +113,6 @@ public void allocateUnassigned(
             unassignedAllocationHandler.removeAndIgnore(allocateUnassignedDecision.getAllocationStatus(), allocation.changes());
         }
     }
-
     protected long getExpectedShardSize(ShardRouting shardRouting, RoutingAllocation allocation) {
         if (shardRouting.primary()) {
             if (shardRouting.recoverySource().getType() == RecoverySource.Type.SNAPSHOT) {
@@ -120,6 +141,12 @@ public abstract AllocateUnassignedDecision makeAllocationDecision(
         Logger logger
     );
 
+    public abstract ConcurrentMap<ShardRouting, AllocateUnassignedDecision> makeAllocationDecision(
+            Set<ShardRouting> shards,
+            RoutingAllocation allocation,
+            Logger logger
+    );
+
     /**
      * Builds decisions for all nodes in the cluster, so that the explain API can provide information on
      * allocation decisions for each node, while still waiting to allocate the shard (e.g. due to fetching shard data).

server/src/main/java/org/opensearch/gateway/PrimaryShardAllocator.java

@@ -59,6 +59,7 @@
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.ConcurrentMap;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -457,6 +458,12 @@ private static NodesToAllocate buildNodesToAllocate(
 
     protected abstract FetchResult<NodeGatewayStartedShards> fetchData(ShardRouting shard, RoutingAllocation allocation);
 
+    @Override
+    // to be override
+    public ConcurrentMap<ShardRouting, AllocateUnassignedDecision> makeAllocationDecision(Set<ShardRouting> shards, RoutingAllocation allocation, Logger logger) {
+        return null;
+    }
+
     private static class NodeShardsResult {
         final List<NodeGatewayStartedShards> orderedAllocationCandidates;
         final int allocationsFound;

server/src/main/java/org/opensearch/gateway/ReplicaShardAllocator.java

@@ -62,6 +62,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ConcurrentMap;
 
 import static org.opensearch.cluster.routing.UnassignedInfo.INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING;
 
@@ -495,6 +496,13 @@ private static boolean canPerformOperationBasedRecovery(
 
     protected abstract AsyncShardFetch.FetchResult<NodeStoreFilesMetadata> fetchData(ShardRouting shard, RoutingAllocation allocation);
 
+    @Override
+    // to be override
+    public ConcurrentMap<ShardRouting, AllocateUnassignedDecision> makeAllocationDecision(Set<ShardRouting> shards, RoutingAllocation allocation, Logger logger) {
+        return null;
+    }
+
+
     /**
      * Returns a boolean indicating whether fetching shard data has been triggered at any point for the given shard.
      */