Bootstrap FC optimization: Interfaces for state build and state transition flows

ambry-api/src/main/java/com/github/ambry/server/StoreManager.java

@@ -34,6 +34,12 @@ public interface StoreManager {
    */
   boolean addBlobStore(ReplicaId replica);
 
+  /**
+   * Build state after filecopy is completed
+   * @param partitionName the partition id for which state is to be built..
+   */
+  void buildStateForFileCopy(String partitionName);
+
   /**
    * Remove store from storage manager.
    * @param id the {@link PartitionId} associated with store

ambry-cloud/src/main/java/com/github/ambry/cloud/CloudStorageManager.java

@@ -56,6 +56,10 @@ public CloudStorageManager(VerifiableProperties properties, VcrMetrics vcrMetric
   public boolean addBlobStore(ReplicaId replica) {
     return createAndStartBlobStoreIfAbsent(replica.getPartitionId()) != null;
   }
+  @Override
+  public void buildStateForFileCopy(String partitionName){
+    // no-op
+  }
 
   @Override
   public boolean shutdownBlobStore(PartitionId id) {

ambry-clustermap/src/main/java/com/github/ambry/clustermap/HelixParticipant.java

@@ -863,6 +863,8 @@ private DataNodeConfig getDataNodeConfig() {
 
   @Override
   public void onPartitionBecomeBootstrapFromOffline(String partitionName) {
+    // TODO: Prefilecopy steps: Handle scenarios for Filceopy -> filecopy, Replication->Filecopy,
+    //  Filceopy -> replication and replication->replication rollout/rollback.
     try {
       // 1. take actions in storage manager (add new replica if necessary)
       PartitionStateChangeListener storageManagerListener =
@@ -871,6 +873,17 @@ public void onPartitionBecomeBootstrapFromOffline(String partitionName) {
         storageManagerListener.onPartitionBecomeBootstrapFromOffline(partitionName);
       }
 
+      /**
+       * Should be invoked after storage manager listener to ensure that the replica is added to the store.
+       * Conditional execution based on requirement for File Copy.
+       */
+      PartitionStateChangeListener fileCopyManagerListener =
+          partitionStateChangeListeners.get(StateModelListenerType.FileCopyManagerListener);
+      if(fileCopyManagerListener != null){
+        fileCopyManagerListener.onPartitionBecomeBootstrapFromOffline(partitionName);
+        replicaSyncUpManager.waitForFileCopyCompleted(partitionName);
+      }
+
       // 2. take actions in replication manager (add new replica if necessary)
       PartitionStateChangeListener replicationManagerListener =
           partitionStateChangeListeners.get(StateModelListenerType.ReplicationManagerListener);

ambry-file-transfer/src/main/java/com/github/ambry/FileCopyManager.java

@@ -41,7 +41,8 @@ class PartitionStateChangeListenerImpl implements PartitionStateChangeListener {
 
     @Override
     public void onPartitionBecomeBootstrapFromOffline(String partitionName) {
-
+      // StateBuilding at the end of FCM's Offline->Bootstrap transition
+      storeManager.buildStateForFileCopy(partitionName);
     }
 
     @Override

ambry-store/src/main/java/com/github/ambry/store/StorageManager.java

@@ -530,6 +530,10 @@ public boolean addBlobStore(ReplicaId replica) {
     logger.info("New store is successfully added into StorageManager");
     return true;
   }
+  @Override
+  public void buildStateForFileCopy(String partitionName){
+    // no-op
+  }
 
   /**
    * If a bootstrap replica fails, try to remove all the files and directories associated with it.
@@ -716,6 +720,8 @@ private class PartitionStateChangeListenerImpl implements PartitionStateChangeLi
 
     @Override
     public void onPartitionBecomeBootstrapFromOffline(String partitionName) {
+      // For Filecopy, 4 steps to be taken up here: Prefilecopy, Filecopy, State Build, Exception handling and cleanup
+
       // check if partition exists on current node
       ReplicaId replica = partitionNameToReplicaId.get(partitionName);
       Store store;
@@ -737,6 +743,8 @@ public void onPartitionBecomeBootstrapFromOffline(String partitionName) {
           // Attempt to add store into storage manager. If store already exists on disk (but not in clustermap), make
           // sure old store of this replica is deleted (this store may be created in previous replica addition but failed
           // at some point). Then a brand new store associated with this replica should be created and started.
+          // TODO: For Filecopy, we do not init the BlobStore since new log/index isn't required, the files will be directly
+          //  copied from remote node.
           if (!addBlobStore(replicaToAdd)) {
             // We have decreased the available disk space in HelixClusterManager#getDiskForBootstrapReplica. Increase it
             // back since addition of store failed.