Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/2194#discussion_r69460544
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/checkpoint/savepoint/FsSavepointStore.java
---
@@ -0,0 +1,225 @@
+/*
+ * 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.runtime.checkpoint.savepoint;
+
+import org.apache.flink.core.fs.FSDataInputStream;
+import org.apache.flink.core.fs.FSDataOutputStream;
+import org.apache.flink.core.fs.FileSystem;
+import org.apache.flink.core.fs.Path;
+import org.apache.flink.util.FileUtils;
+import org.apache.flink.util.Preconditions;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+import static org.apache.flink.util.Preconditions.checkNotNull;
+
+/**
+ * A file system based {@link SavepointStore}.
+ *
+ * <p>Stored savepoints have the following format:
+ * <pre>
+ * MagicNumber SavepointVersion Savepoint
+ * - MagicNumber => int
+ * - SavepointVersion => int (returned by Savepoint#getVersion())
+ * - Savepoint => bytes (serialized via version-specific
SavepointSerializer)
+ * </pre>
+ */
+public class FsSavepointStore implements SavepointStore {
+
+ private static final Logger LOG =
LoggerFactory.getLogger(FsSavepointStore.class);
+
+ /** Magic number for sanity checks against stored savepoints. */
+ int MAGIC_NUMBER = 0x4960672d;
+
+ /** Root path for savepoints. */
+ private final Path rootPath;
+
+ /** Prefix for savepoint files. */
+ private final String prefix;
+
+ /** File system to use for file access. */
+ private final FileSystem fileSystem;
+
+ /**
+ * Creates a new file system based {@link SavepointStore}.
+ *
+ * @param rootPath Root path for savepoints
+ * @param prefix Prefix for savepoint files
+ * @throws IOException On failure to access root path
+ */
+ FsSavepointStore(String rootPath, String prefix) throws IOException {
+ this.rootPath = new Path(checkNotNull(rootPath, "Root path"));
+ this.prefix = checkNotNull(prefix, "Prefix");
+
+ this.fileSystem = FileSystem.get(this.rootPath.toUri());
+ }
+
+ @Override
+ public <T extends Savepoint> String storeSavepoint(T savepoint) throws
IOException {
+ Preconditions.checkNotNull(savepoint, "Savepoint");
+
+ Exception latestException = null;
+ Path path = null;
+ FSDataOutputStream fdos = null;
+
+ // Try to create a FS output stream
+ for (int attempt = 0; attempt < 10; attempt++) {
+ path = new Path(rootPath,
FileUtils.getRandomFilename(prefix));
+ try {
+ fdos = fileSystem.create(path, false);
+ break;
+ } catch (Exception e) {
+ latestException = e;
+ }
+ }
+
+ if (fdos == null) {
+ throw new IOException("Failed to create file output
stream at " + path, latestException);
+ }
+
+ boolean success = false;
+ try (DataOutputStream dos = new DataOutputStream(fdos)) {
+ // Write header
+ dos.writeInt(MAGIC_NUMBER);
+ dos.writeInt(savepoint.getVersion());
+
+ // Write savepoint
+ SavepointSerializer<T> serializer =
SavepointSerializers.getSerializer(savepoint);
+ serializer.serialize(savepoint, fdos);
+ success = true;
+ } finally {
+ fdos.close();
+
+ if (!success && fileSystem.exists(path)) {
+ if (!fileSystem.delete(path, true)) {
+ LOG.warn("Failed to delete file " +
path + " after failed write.");
+ }
+ }
+ }
+
+ return path.toString();
+ }
+
+ @Override
+ public Savepoint loadSavepoint(String path) throws IOException {
+ Preconditions.checkNotNull(path, "Path");
+
+ try {
+ try (FSDataInputStream fdis = createFsInputStream(new
Path(path))) {
+ try (DataInputStream dis = new
DataInputStream(fdis)) {
+ int magicNumber = dis.readInt();
+ int version = dis.readInt();
+
+ if (magicNumber == MAGIC_NUMBER) {
+ SavepointSerializer<?>
serializer = SavepointSerializers.getSerializer(version);
+ Savepoint savepoint =
serializer.deserialize(fdis);
+ return savepoint;
+ } else {
+ throw new
IllegalStateException("Unexpected magic number. This indicates " +
+ "that the
specified file is not a proper savepoint or " +
+ "the file has
been corrupted.");
+ }
+ }
+ }
+ } catch (Throwable t) {
--- End diff --
Exceptions which are thrown due to a wrong path or because the input stream
couldn't be opened will also trigger the savepoint version 0 loading. Maybe we
could differentiate between unable to open file stream and wrong magic number
or unable to read version.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
