dawidwys commented on a change in pull request #6711: [FLINK-9377] [core, state backends] Remove serializers from checkpoints URL: https://github.com/apache/flink/pull/6711#discussion_r223310411
########## File path: flink-core/src/main/java/org/apache/flink/api/common/typeutils/TypeSerializerSnapshotSerializationUtil.java ########## @@ -0,0 +1,208 @@ +/* + * 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.flink.api.common.typeutils; + +import org.apache.flink.core.io.VersionedIOReadableWritable; +import org.apache.flink.core.memory.DataInputView; +import org.apache.flink.core.memory.DataOutputView; +import org.apache.flink.util.InstantiationUtil; +import org.apache.flink.util.Preconditions; + +import javax.annotation.Nullable; +import java.io.IOException; + +/** + * Utility methods for serialization of {@link TypeSerializerSnapshot}. + */ +public class TypeSerializerSnapshotSerializationUtil { + + /** + * Writes a {@link TypeSerializerSnapshot} to the provided data output view. + * + * <p>It is written with a format that can be later read again using + * {@link #readSerializerSnapshot(DataInputView, ClassLoader, TypeSerializer)}. + * + * @param out the data output view + * @param serializerSnapshot the serializer configuration snapshot to write + * @param serializer the prior serializer. This needs to be written of the serializer snapshot + * if the serializer snapshot is still the legacy {@link TypeSerializerConfigSnapshot}. + * + * @throws IOException + */ + public static <T> void writeSerializerSnapshot( + DataOutputView out, + TypeSerializerSnapshot<T> serializerSnapshot, + TypeSerializer<T> serializer) throws IOException { + + new TypeSerializerSnapshotSerializationProxy<>(serializerSnapshot, serializer).write(out); + } + + /** + * Reads from a data input view a {@link TypeSerializerSnapshot} that was previously + * written using {@link TypeSerializerSnapshotSerializationUtil#writeSerializerSnapshot(DataOutputView, TypeSerializerSnapshot, TypeSerializer)}. + * + * @param in the data input view + * @param userCodeClassLoader the user code class loader to use + * @param existingPriorSerializer the prior serializer. This would only be non-null if we are + * restoring from a snapshot taken with Flink version <= 1.6. + * + * @return the read serializer configuration snapshot + * + * @throws IOException + */ + public static <T> TypeSerializerSnapshot<T> readSerializerSnapshot( + DataInputView in, + ClassLoader userCodeClassLoader, + @Nullable TypeSerializer<T> existingPriorSerializer) throws IOException { + + final TypeSerializerSnapshotSerializationProxy<T> proxy = + new TypeSerializerSnapshotSerializationProxy<>(userCodeClassLoader, existingPriorSerializer); + proxy.read(in); + + return proxy.getSerializerSnapshot(); + } + + /** + * Utility serialization proxy for a {@link TypeSerializerSnapshot}. + */ + static final class TypeSerializerSnapshotSerializationProxy<T> extends VersionedIOReadableWritable { + + private static final int VERSION = 2; + + private ClassLoader userCodeClassLoader; + private TypeSerializerSnapshot<T> serializerSnapshot; + private TypeSerializer<T> serializer; + + TypeSerializerSnapshotSerializationProxy( + ClassLoader userCodeClassLoader, + @Nullable TypeSerializer<T> existingPriorSerializer) { + this.userCodeClassLoader = Preconditions.checkNotNull(userCodeClassLoader); + this.serializer = existingPriorSerializer; + } + + TypeSerializerSnapshotSerializationProxy( + TypeSerializerSnapshot<T> serializerConfigSnapshot, + TypeSerializer<T> serializer) { + this.serializerSnapshot = Preconditions.checkNotNull(serializerConfigSnapshot); + this.serializer = Preconditions.checkNotNull(serializer); + } + + /** + * Binary format layout of a written serializer snapshot is as follows: + * + * <ul> + * <li>1. Serializer snapshot classname (UTF).</li> + * <li>2. The originating serializer of the snapshot, if any, written via Java serialization. + * Presence of the serializer is indicated by a flag (boolean -> TypeSerializer).</li> + * <li>3. The version of the serializer snapshot's binary format.</li> + * <li>4. The actual serializer snapshot.</li> + * </ul> + */ + @Override + public void write(DataOutputView out) throws IOException { + super.write(out); + + // config snapshot class, so that we can re-instantiate the + // correct type of config snapshot instance when deserializing + out.writeUTF(serializerSnapshot.getClass().getName()); + + if (serializerSnapshot instanceof TypeSerializerConfigSnapshot) { + // backwards compatible path, where the serializer snapshot is still using the + // deprecated interface; the originating serializer needs to be written to the byte stream + out.writeBoolean(true); + @SuppressWarnings("unchecked") + TypeSerializerConfigSnapshot<T> legacySerializerSnapshot = (TypeSerializerConfigSnapshot<T>) serializerSnapshot; + TypeSerializerSerializationUtil.writeSerializer(out, serializer); + + // TypeSerializerConfigSnapshot includes the version number implicitly when it is written + legacySerializerSnapshot.write(out); + } else { + out.writeBoolean(false); + + out.writeInt(serializerSnapshot.getCurrentVersion()); + serializerSnapshot.write(out); + } + } + + @SuppressWarnings("unchecked") + @Override + public void read(DataInputView in) throws IOException { + super.read(in); + + String serializerConfigClassname = in.readUTF(); + Class<? extends TypeSerializerSnapshot> serializerConfigSnapshotClass; + try { + serializerConfigSnapshotClass = (Class<? extends TypeSerializerSnapshot>) + Class.forName(serializerConfigClassname, false, userCodeClassLoader); + } catch (ClassNotFoundException e) { + throw new IOException( + "Could not find requested TypeSerializerConfigSnapshot class " + + serializerConfigClassname + " in classpath.", e); + } + + serializerSnapshot = InstantiationUtil.instantiate(serializerConfigSnapshotClass); + + if (getReadVersion() >= 2) { Review comment: Could you add a few comments, which branch corresponds to which flink version/snapshot version? This is quite important code block imho. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
