2 * Copyright (c) 2017 Brocade Communications Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.controller.cluster.persistence;
10 import akka.actor.ExtendedActorSystem;
11 import akka.dispatch.Futures;
12 import akka.persistence.SelectedSnapshot;
13 import akka.persistence.SnapshotMetadata;
14 import akka.persistence.SnapshotSelectionCriteria;
15 import akka.persistence.serialization.Snapshot;
16 import akka.persistence.serialization.SnapshotSerializer;
17 import akka.persistence.snapshot.japi.SnapshotStore;
18 import akka.serialization.JavaSerializer;
19 import com.google.common.annotations.VisibleForTesting;
20 import com.google.common.io.ByteStreams;
21 import com.typesafe.config.Config;
22 import java.io.BufferedInputStream;
24 import java.io.FileInputStream;
25 import java.io.FileOutputStream;
26 import java.io.IOException;
27 import java.io.InputStream;
28 import java.io.ObjectInputStream;
29 import java.io.ObjectOutputStream;
30 import java.io.UnsupportedEncodingException;
31 import java.net.URLDecoder;
32 import java.net.URLEncoder;
33 import java.nio.charset.StandardCharsets;
34 import java.nio.file.Files;
35 import java.nio.file.StandardCopyOption;
36 import java.util.ArrayDeque;
37 import java.util.Arrays;
38 import java.util.Collection;
39 import java.util.Collections;
40 import java.util.Deque;
41 import java.util.List;
42 import java.util.Optional;
43 import java.util.concurrent.Callable;
44 import java.util.stream.Collector;
45 import java.util.stream.Collectors;
46 import java.util.stream.Stream;
47 import javax.annotation.Nullable;
48 import org.slf4j.Logger;
49 import org.slf4j.LoggerFactory;
50 import scala.concurrent.ExecutionContext;
51 import scala.concurrent.Future;
54 * Akka SnapshotStore implementation backed by the local file system. This class was patterned after akka's
55 * LocalSnapshotStore class and exists because akka's version serializes to a byte[] before persisting
56 * to the file which will fail if the data reaches or exceeds Integer.MAX_VALUE in size. This class avoids that issue
57 * by serializing the data directly to the file.
59 * @author Thomas Pantelis
61 public class LocalSnapshotStore extends SnapshotStore {
62 private static final Logger LOG = LoggerFactory.getLogger(LocalSnapshotStore.class);
64 private static final int PERSISTENCE_ID_START_INDEX = "snapshot-".length();
66 private final ExecutionContext executionContext;
67 private final int maxLoadAttempts;
68 private final File snapshotDir;
70 public LocalSnapshotStore(final Config config) {
71 this.executionContext = context().system().dispatchers().lookup(config.getString("stream-dispatcher"));
72 snapshotDir = new File(config.getString("dir"));
74 int localMaxLoadAttempts = config.getInt("max-load-attempts");
75 maxLoadAttempts = localMaxLoadAttempts > 0 ? localMaxLoadAttempts : 1;
77 LOG.debug("LocalSnapshotStore ctor: snapshotDir: {}, maxLoadAttempts: {}", snapshotDir, maxLoadAttempts);
81 public void preStart() throws Exception {
82 if (!snapshotDir.isDirectory()) {
83 // Try to create the directory, on failure double check if someone else beat us to it.
84 if (!snapshotDir.mkdirs() && !snapshotDir.isDirectory()) {
85 throw new IOException("Failed to create snapshot directory " + snapshotDir.getCanonicalPath());
93 public Future<Optional<SelectedSnapshot>> doLoadAsync(final String persistenceId,
94 final SnapshotSelectionCriteria criteria) {
95 LOG.debug("In doLoadAsync - persistenceId: {}, criteria: {}", persistenceId, criteria);
97 // Select the youngest 'maxLoadAttempts' snapshots that match the criteria. This may help in situations where
98 // saving of a snapshot could not be completed because of a JVM crash. Hence, an attempt to load that snapshot
99 // will fail but loading an older snapshot may succeed.
101 Deque<SnapshotMetadata> metadatas = getSnapshotMetadatas(persistenceId, criteria).stream()
102 .sorted(LocalSnapshotStore::compare).collect(reverse()).stream().limit(maxLoadAttempts)
103 .collect(Collectors.toCollection(ArrayDeque::new));
105 if (metadatas.isEmpty()) {
106 return Futures.successful(Optional.empty());
109 LOG.debug("doLoadAsync - found: {}", metadatas);
111 return Futures.future(() -> doLoad(metadatas), executionContext);
114 private Optional<SelectedSnapshot> doLoad(final Deque<SnapshotMetadata> metadatas) throws IOException {
115 SnapshotMetadata metadata = metadatas.removeFirst();
116 File file = toSnapshotFile(metadata);
118 LOG.debug("doLoad {}", file);
121 Object data = deserialize(file);
123 LOG.debug("deserialized data: {}", data);
125 return Optional.of(new SelectedSnapshot(metadata, data));
126 } catch (IOException e) {
127 LOG.error("Error loading snapshot file {}, remaining attempts: {}", file, metadatas.size(), e);
129 if (metadatas.isEmpty()) {
133 return doLoad(metadatas);
137 private Object deserialize(final File file) throws IOException {
138 return JavaSerializer.currentSystem().withValue((ExtendedActorSystem) context().system(),
139 (Callable<Object>) () -> {
140 try (ObjectInputStream in = new ObjectInputStream(new FileInputStream(file))) {
141 return in.readObject();
142 } catch (ClassNotFoundException e) {
143 throw new IOException("Error loading snapshot file " + file, e);
144 } catch (IOException e) {
145 LOG.debug("Error loading snapshot file {}", file, e);
146 return tryDeserializeAkkaSnapshot(file);
151 private Object tryDeserializeAkkaSnapshot(final File file) throws IOException {
152 LOG.debug("tryDeserializeAkkaSnapshot {}", file);
154 // The snapshot was probably previously stored via akka's LocalSnapshotStore which wraps the data
155 // in a Snapshot instance and uses the SnapshotSerializer to serialize it to a byte[]. So we'll use
156 // the SnapshotSerializer to try to de-serialize it.
158 SnapshotSerializer snapshotSerializer = new SnapshotSerializer((ExtendedActorSystem) context().system());
160 try (InputStream in = new BufferedInputStream(new FileInputStream(file))) {
161 return ((Snapshot)snapshotSerializer.fromBinary(ByteStreams.toByteArray(in))).data();
166 public Future<Void> doSaveAsync(final SnapshotMetadata metadata, final Object snapshot) {
167 LOG.debug("In doSaveAsync - metadata: {}, snapshot: {}", metadata, snapshot);
169 return Futures.future(() -> doSave(metadata, snapshot), executionContext);
172 private Void doSave(final SnapshotMetadata metadata, final Object snapshot) throws IOException {
173 final File actual = toSnapshotFile(metadata);
174 final File temp = File.createTempFile(actual.getName(), null, snapshotDir);
176 LOG.debug("Saving to temp file: {}", temp);
178 try (ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(temp))) {
179 out.writeObject(snapshot);
180 } catch (IOException e) {
181 LOG.error("Error saving snapshot file {}. Deleting file..", temp, e);
182 if (!temp.delete()) {
183 LOG.error("Failed to successfully delete file {}", temp);
188 LOG.debug("Renaming to: {}", actual);
190 Files.move(temp.toPath(), actual.toPath(), StandardCopyOption.ATOMIC_MOVE);
191 } catch (IOException e) {
192 LOG.warn("Failed to move {} to {}. Deleting {}..", temp, actual, temp, e);
193 if (!temp.delete()) {
194 LOG.error("Failed to successfully delete file {}", temp);
203 public Future<Void> doDeleteAsync(final SnapshotMetadata metadata) {
204 LOG.debug("In doDeleteAsync - metadata: {}", metadata);
206 // Multiple snapshot files here mean that there were multiple snapshots for this seqNr - we delete all of them.
207 // Usually snapshot-stores would keep one snapshot per sequenceNr however here in the file-based one we
208 // timestamp snapshots and allow multiple to be kept around (for the same seqNr) if desired.
210 return Futures.future(() -> doDelete(metadata), executionContext);
214 public Future<Void> doDeleteAsync(final String persistenceId, final SnapshotSelectionCriteria criteria) {
215 LOG.debug("In doDeleteAsync - persistenceId: {}, criteria: {}", persistenceId, criteria);
217 return Futures.future(() -> doDelete(persistenceId, criteria), executionContext);
220 private Void doDelete(final String persistenceId, final SnapshotSelectionCriteria criteria) {
221 final List<File> files = getSnapshotMetadatas(persistenceId, criteria).stream()
222 .flatMap(md -> Stream.of(toSnapshotFile(md))).collect(Collectors.toList());
224 LOG.debug("Deleting files: {}", files);
226 files.forEach(File::delete);
230 private Void doDelete(final SnapshotMetadata metadata) {
231 final Collection<File> files = getSnapshotFiles(metadata);
233 LOG.debug("Deleting files: {}", files);
235 files.forEach(File::delete);
239 private Collection<File> getSnapshotFiles(final String persistenceId) {
240 String encodedPersistenceId = encode(persistenceId);
242 File[] files = snapshotDir.listFiles((dir, name) -> {
243 int persistenceIdEndIndex = name.lastIndexOf('-', name.lastIndexOf('-') - 1);
244 return PERSISTENCE_ID_START_INDEX + encodedPersistenceId.length() == persistenceIdEndIndex
245 && name.startsWith(encodedPersistenceId, PERSISTENCE_ID_START_INDEX) && !name.endsWith(".tmp");
249 return Collections.emptyList();
252 if (LOG.isDebugEnabled()) {
253 LOG.debug("getSnapshotFiles for persistenceId: {}, found files: {}", encodedPersistenceId,
254 Arrays.toString(files));
257 return Arrays.asList(files);
260 private Collection<File> getSnapshotFiles(final SnapshotMetadata metadata) {
261 return getSnapshotFiles(metadata.persistenceId()).stream().filter(file -> {
262 SnapshotMetadata possible = extractMetadata(file);
263 return possible != null && possible.sequenceNr() == metadata.sequenceNr()
264 && (metadata.timestamp() == 0L || possible.timestamp() == metadata.timestamp());
265 }).collect(Collectors.toList());
268 private Collection<SnapshotMetadata> getSnapshotMetadatas(final String persistenceId,
269 final SnapshotSelectionCriteria criteria) {
270 return getSnapshotFiles(persistenceId).stream().flatMap(file -> toStream(extractMetadata(file)))
271 .filter(criteria::matches).collect(Collectors.toList());
274 private static Stream<SnapshotMetadata> toStream(@Nullable final SnapshotMetadata md) {
275 return md != null ? Stream.of(md) : Stream.empty();
279 private static SnapshotMetadata extractMetadata(final File file) {
280 String name = file.getName();
281 int sequenceNumberEndIndex = name.lastIndexOf('-');
282 int persistenceIdEndIndex = name.lastIndexOf('-', sequenceNumberEndIndex - 1);
283 if (PERSISTENCE_ID_START_INDEX >= persistenceIdEndIndex) {
288 // Since the persistenceId is url encoded in the filename, we need
289 // to decode relevant filename's part to obtain persistenceId back
290 String persistenceId = decode(name.substring(PERSISTENCE_ID_START_INDEX, persistenceIdEndIndex));
291 long sequenceNumber = Long.parseLong(name.substring(persistenceIdEndIndex + 1, sequenceNumberEndIndex));
292 long timestamp = Long.parseLong(name.substring(sequenceNumberEndIndex + 1));
293 return new SnapshotMetadata(persistenceId, sequenceNumber, timestamp);
294 } catch (NumberFormatException e) {
299 private File toSnapshotFile(final SnapshotMetadata metadata) {
300 return new File(snapshotDir, String.format("snapshot-%s-%d-%d", encode(metadata.persistenceId()),
301 metadata.sequenceNr(), metadata.timestamp()));
304 private static <T> Collector<T, ?, List<T>> reverse() {
305 return Collectors.collectingAndThen(Collectors.toList(), list -> {
306 Collections.reverse(list);
311 private static String encode(final String str) {
313 return URLEncoder.encode(str, StandardCharsets.UTF_8.name());
314 } catch (UnsupportedEncodingException e) {
316 LOG.warn("Error encoding {}", str, e);
321 private static String decode(final String str) {
323 return URLDecoder.decode(str, StandardCharsets.UTF_8.name());
324 } catch (final UnsupportedEncodingException e) {
326 LOG.warn("Error decoding {}", str, e);
332 static int compare(final SnapshotMetadata m1, final SnapshotMetadata m2) {
333 return (int) (!m1.persistenceId().equals(m2.persistenceId())
334 ? m1.persistenceId().compareTo(m2.persistenceId()) :
335 m1.sequenceNr() != m2.sequenceNr() ? m1.sequenceNr() - m2.sequenceNr() :
336 m1.timestamp() != m2.timestamp() ? m1.timestamp() - m2.timestamp() : 0);