HDFS-10882. Federation State Store Interface API. Contributed by Jason Kace and Inigo Goiri.

(cherry picked from commit 6d94c90ece)
(cherry picked from commit 2c740a684a)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java

@@ -24,6 +24,7 @@ import org.apache.hadoop.hdfs.client.HdfsClientConfigKeys;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.RamDiskReplicaLruTracker;
+import org.apache.hadoop.hdfs.server.federation.store.driver.impl.StateStoreSerializerPBImpl;
 import org.apache.hadoop.http.HttpConfig;
 
 /** 
@@ -1018,6 +1019,16 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
   public static final String FEDERATION_NAMENODE_RESOLVER_CLIENT_CLASS_DEFAULT =
       "org.apache.hadoop.hdfs.server.federation.MockResolver";
 
+  // HDFS Router-based federation State Store
+  public static final String FEDERATION_STORE_PREFIX =
+      FEDERATION_ROUTER_PREFIX + "store.";
+
+  public static final String FEDERATION_STORE_SERIALIZER_CLASS =
+      DFSConfigKeys.FEDERATION_STORE_PREFIX + "serializer";
+  public static final Class<StateStoreSerializerPBImpl>
+      FEDERATION_STORE_SERIALIZER_CLASS_DEFAULT =
+          StateStoreSerializerPBImpl.class;
+
   // dfs.client.retry confs are moved to HdfsClientConfigKeys.Retry 
   @Deprecated
   public static final String  DFS_CLIENT_RETRY_POLICY_ENABLED_KEY

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/federation/store/RecordStore.java

@@ -0,0 +1,100 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.federation.store;
+
+import java.lang.reflect.Constructor;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.hdfs.server.federation.store.driver.StateStoreDriver;
+import org.apache.hadoop.hdfs.server.federation.store.records.BaseRecord;
+
+/**
+ * Store records in the State Store. Subclasses provide interfaces to operate on
+ * those records.
+ *
+ * @param <R> Record to store by this interface.
+ */
+@InterfaceAudience.Private
+@InterfaceStability.Evolving
+public abstract class RecordStore<R extends BaseRecord> {
+
+  private static final Log LOG = LogFactory.getLog(RecordStore.class);
+
+
+  /** Class of the record stored in this State Store. */
+  private final Class<R> recordClass;
+
+  /** State store driver backed by persistent storage. */
+  private final StateStoreDriver driver;
+
+
+  /**
+   * Create a new store for records.
+   *
+   * @param clazz Class of the record to store.
+   * @param stateStoreDriver Driver for the State Store.
+   */
+  protected RecordStore(Class<R> clazz, StateStoreDriver stateStoreDriver) {
+    this.recordClass = clazz;
+    this.driver = stateStoreDriver;
+  }
+
+  /**
+   * Report a required record to the data store. The data store uses this to
+   * create/maintain storage for the record.
+   *
+   * @return The class of the required record or null if no record is required
+   *         for this interface.
+   */
+  public Class<R> getRecordClass() {
+    return this.recordClass;
+  }
+
+  /**
+   * Get the State Store driver.
+   *
+   * @return State Store driver.
+   */
+  protected StateStoreDriver getDriver() {
+    return this.driver;
+  }
+
+  /**
+   * Build a state store API implementation interface.
+   *
+   * @param interfaceClass The specific interface implementation to create
+   * @param driver The {@link StateStoreDriver} implementation in use.
+   * @return An initialized instance of the specified state store API
+   *         implementation.
+   */
+  public static <T extends RecordStore<?>> T newInstance(
+      final Class<T> clazz, final StateStoreDriver driver) {
+
+    try {
+      Constructor<T> constructor = clazz.getConstructor(StateStoreDriver.class);
+      T recordStore = constructor.newInstance(driver);
+      return recordStore;
+    } catch (Exception e) {
+      LOG.error("Cannot create new instance for " + clazz, e);
+      return null;
+    }
+  }
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/federation/store/driver/StateStoreSerializer.java

@@ -0,0 +1,119 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.federation.store.driver;
+
+import java.io.IOException;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
+import org.apache.hadoop.hdfs.server.federation.store.records.BaseRecord;
+import org.apache.hadoop.util.ReflectionUtils;
+
+/**
+ * Serializer to store and retrieve data in the State Store.
+ */
+public abstract class StateStoreSerializer {
+
+  /** Singleton for the serializer instance. */
+  private static StateStoreSerializer defaultSerializer;
+
+  /**
+   * Get the default serializer based.
+   * @return Singleton serializer.
+   */
+  public static StateStoreSerializer getSerializer() {
+    return getSerializer(null);
+  }
+
+  /**
+   * Get a serializer based on the provided configuration.
+   * @param conf Configuration. Default if null.
+   * @return Singleton serializer.
+   */
+  public static StateStoreSerializer getSerializer(Configuration conf) {
+    if (conf == null) {
+      synchronized (StateStoreSerializer.class) {
+        if (defaultSerializer == null) {
+          conf = new Configuration();
+          defaultSerializer = newSerializer(conf);
+        }
+      }
+      return defaultSerializer;
+    } else {
+      return newSerializer(conf);
+    }
+  }
+
+  private static StateStoreSerializer newSerializer(final Configuration conf) {
+    Class<? extends StateStoreSerializer> serializerName = conf.getClass(
+        DFSConfigKeys.FEDERATION_STORE_SERIALIZER_CLASS,
+        DFSConfigKeys.FEDERATION_STORE_SERIALIZER_CLASS_DEFAULT,
+        StateStoreSerializer.class);
+    return ReflectionUtils.newInstance(serializerName, conf);
+  }
+
+  /**
+   * Create a new record.
+   * @param clazz Class of the new record.
+   * @return New record.
+   */
+  public static <T> T newRecord(Class<T> clazz) {
+    return getSerializer(null).newRecordInstance(clazz);
+  }
+
+  /**
+   * Create a new record.
+   * @param clazz Class of the new record.
+   * @return New record.
+   */
+  public abstract <T> T newRecordInstance(Class<T> clazz);
+
+  /**
+   * Serialize a record into a byte array.
+   * @param record Record to serialize.
+   * @return Byte array with the serialized record.
+   */
+  public abstract byte[] serialize(BaseRecord record);
+
+  /**
+   * Serialize a record into a string.
+   * @param record Record to serialize.
+   * @return String with the serialized record.
+   */
+  public abstract String serializeString(BaseRecord record);
+
+  /**
+   * Deserialize a bytes array into a record.
+   * @param byteArray Byte array to deserialize.
+   * @param clazz Class of the record.
+   * @return New record.
+   * @throws IOException If it cannot deserialize the record.
+   */
+  public abstract <T extends BaseRecord> T deserialize(
+      byte[] byteArray, Class<T> clazz) throws IOException;
+
+  /**
+   * Deserialize a string into a record.
+   * @param data String with the data to deserialize.
+   * @param clazz Class of the record.
+   * @return New record.
+   * @throws IOException If it cannot deserialize the record.
+   */
+  public abstract <T extends BaseRecord> T deserialize(
+      String data, Class<T> clazz) throws IOException;
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/federation/store/driver/impl/StateStoreSerializerPBImpl.java

@@ -0,0 +1,115 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.federation.store.driver.impl;
+
+import java.io.IOException;
+
+import org.apache.commons.codec.binary.Base64;
+import org.apache.commons.codec.binary.StringUtils;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hdfs.server.federation.store.driver.StateStoreSerializer;
+import org.apache.hadoop.hdfs.server.federation.store.records.BaseRecord;
+import org.apache.hadoop.hdfs.server.federation.store.records.impl.pb.PBRecord;
+import org.apache.hadoop.util.ReflectionUtils;
+
+import com.google.protobuf.Message;
+
+/**
+ * Protobuf implementation of the State Store serializer.
+ */
+public final class StateStoreSerializerPBImpl extends StateStoreSerializer {
+
+  private static final String PB_IMPL_PACKAGE_SUFFIX = "impl.pb";
+  private static final String PB_IMPL_CLASS_SUFFIX = "PBImpl";
+
+  private Configuration localConf = new Configuration();
+
+
+  private StateStoreSerializerPBImpl() {
+  }
+
+  @Override
+  @SuppressWarnings("unchecked")
+  public <T> T newRecordInstance(Class<T> clazz) {
+    try {
+      String clazzPBImpl = getPBImplClassName(clazz);
+      Class<?> pbClazz = localConf.getClassByName(clazzPBImpl);
+      Object retObject = ReflectionUtils.newInstance(pbClazz, localConf);
+      return (T)retObject;
+    } catch (ClassNotFoundException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  private String getPBImplClassName(Class<?> clazz) {
+    String srcPackagePart = getPackageName(clazz);
+    String srcClassName = getClassName(clazz);
+    String destPackagePart = srcPackagePart + "." + PB_IMPL_PACKAGE_SUFFIX;
+    String destClassPart = srcClassName + PB_IMPL_CLASS_SUFFIX;
+    return destPackagePart + "." + destClassPart;
+  }
+
+  private String getClassName(Class<?> clazz) {
+    String fqName = clazz.getName();
+    return (fqName.substring(fqName.lastIndexOf(".") + 1, fqName.length()));
+  }
+
+  private String getPackageName(Class<?> clazz) {
+    return clazz.getPackage().getName();
+  }
+
+  @Override
+  public byte[] serialize(BaseRecord record) {
+    byte[] byteArray64 = null;
+    if (record instanceof PBRecord) {
+      PBRecord recordPB = (PBRecord) record;
+      Message msg = recordPB.getProto();
+      byte[] byteArray = msg.toByteArray();
+      byteArray64 = Base64.encodeBase64(byteArray, false);
+    }
+    return byteArray64;
+  }
+
+  @Override
+  public String serializeString(BaseRecord record) {
+    byte[] byteArray64 = serialize(record);
+    String base64Encoded = StringUtils.newStringUtf8(byteArray64);
+    return base64Encoded;
+  }
+
+  @Override
+  public <T extends BaseRecord> T deserialize(
+      byte[] byteArray, Class<T> clazz) throws IOException {
+
+    T record = newRecord(clazz);
+    if (record instanceof PBRecord) {
+      PBRecord pbRecord = (PBRecord) record;
+      byte[] byteArray64 = Base64.encodeBase64(byteArray, false);
+      String base64Encoded = StringUtils.newStringUtf8(byteArray64);
+      pbRecord.readInstance(base64Encoded);
+    }
+    return record;
+  }
+
+  @Override
+  public <T extends BaseRecord> T deserialize(String data, Class<T> clazz)
+      throws IOException {
+    byte[] byteArray64 = Base64.decodeBase64(data);
+    return deserialize(byteArray64, clazz);
+  }
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/federation/store/records/impl/pb/PBRecord.java

@@ -0,0 +1,47 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.federation.store.records.impl.pb;
+
+import java.io.IOException;
+
+import com.google.protobuf.Message;
+
+/**
+ * A record implementation using Protobuf.
+ */
+public interface PBRecord {
+
+  /**
+   * Get the protocol for the record.
+   * @return The protocol for this record.
+   */
+  Message getProto();
+
+  /**
+   * Set the protocol for the record.
+   * @param proto Protocol for this record.
+   */
+  void setProto(Message proto);
+
+  /**
+   * Populate this record with serialized data.
+   * @param base64String Serialized data in base64.
+   * @throws IOException If it cannot read the data.
+   */
+  void readInstance(String base64String) throws IOException;
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/federation/store/records/impl/pb/package-info.java

@@ -0,0 +1,29 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * The protobuf implementations of state store data records defined in the
+ * org.apache.hadoop.hdfs.server.federation.store.records package. Each
+ * implementation wraps an associated protobuf proto definition.
+ */
+@InterfaceAudience.Private
+@InterfaceStability.Evolving
+package org.apache.hadoop.hdfs.server.federation.store.records.impl.pb;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;

hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml

@@ -4370,4 +4370,12 @@
     </description>
   </property>
 
+  <property>
+    <name>dfs.federation.router.store.serializer</name>
+    <value>org.apache.hadoop.hdfs.server.federation.store.driver.impl.StateStoreSerializerPBImpl</value>
+    <description>
+      Class to serialize State Store records.
+    </description>
+  </property>
+
 </configuration>