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 com.google.common.annotations.VisibleForTesting;
19 import com.google.common.io.ByteStreams;
20 import com.typesafe.config.Config;
21 import java.io.BufferedInputStream;
23 import java.io.FileInputStream;
24 import java.io.FileOutputStream;
25 import java.io.FilenameFilter;
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.URLEncoder;
32 import java.nio.charset.StandardCharsets;
33 import java.util.ArrayDeque;
34 import java.util.Arrays;
35 import java.util.Collection;
36 import java.util.Collections;
37 import java.util.Deque;
38 import java.util.List;
39 import java.util.Optional;
40 import java.util.stream.Collector;
41 import java.util.stream.Collectors;
42 import java.util.stream.Stream;
43 import javax.annotation.Nullable;
44 import org.slf4j.Logger;
45 import org.slf4j.LoggerFactory;
46 import scala.concurrent.ExecutionContext;
47 import scala.concurrent.Future;
50 * Akka SnapshotStore implementation backed by the local file system. This class was patterned after akka's
51 * LocalSnapshotStore class and exists because akka's version serializes to a byte[] before persisting
52 * to the file which will fail if the data reaches or exceeds Integer.MAX_VALUE in size. This class avoids that issue
53 * by serializing the data directly to the file.
55 * @author Thomas Pantelis
57 public class LocalSnapshotStore extends SnapshotStore {
58 private static final Logger LOG = LoggerFactory.getLogger(LocalSnapshotStore.class);
60 private static final int PERSISTENCE_ID_START_INDEX = "snapshot-".length();
62 private final ExecutionContext executionContext;
63 private final int maxLoadAttempts;
64 private final File snapshotDir;
66 public LocalSnapshotStore(Config config) {
67 this.executionContext = context().system().dispatchers().lookup(config.getString("stream-dispatcher"));
68 snapshotDir = new File(config.getString("dir"));
70 int localMaxLoadAttempts = config.getInt("max-load-attempts");
71 maxLoadAttempts = localMaxLoadAttempts > 0 ? localMaxLoadAttempts : 1;
73 LOG.debug("LocalSnapshotStore ctor: snapshotDir: {}, maxLoadAttempts: {}", snapshotDir, maxLoadAttempts);
77 public void preStart() throws Exception {
78 if (!snapshotDir.isDirectory()) {
79 // Try to create the directory, on failure double check if someone else beat us to it.
80 if (!snapshotDir.mkdirs() && !snapshotDir.isDirectory()) {
81 throw new IOException("Failed to create snapshot directory " + snapshotDir.getCanonicalPath());
89 public Future<Optional<SelectedSnapshot>> doLoadAsync(String persistenceId, SnapshotSelectionCriteria criteria) {
90 LOG.debug("In doLoadAsync - persistenceId: {}, criteria: {}", persistenceId, criteria);
92 // Select the youngest 'maxLoadAttempts' snapshots that match the criteria. This may help in situations where
93 // saving of a snapshot could not be completed because of a JVM crash. Hence, an attempt to load that snapshot
94 // will fail but loading an older snapshot may succeed.
96 Deque<SnapshotMetadata> metadatas = getSnapshotMetadatas(persistenceId, criteria).stream()
97 .sorted(LocalSnapshotStore::compare).collect(reverse()).stream().limit(maxLoadAttempts)
98 .collect(Collectors.toCollection(ArrayDeque::new));
100 if (metadatas.isEmpty()) {
101 return Futures.successful(Optional.empty());
104 LOG.debug("doLoadAsync - found: {}", metadatas);
106 return Futures.future(() -> doLoad(metadatas), executionContext);
109 private Optional<SelectedSnapshot> doLoad(Deque<SnapshotMetadata> metadatas) throws IOException {
110 SnapshotMetadata metadata = metadatas.removeFirst();
111 File file = toSnapshotFile(metadata, "");
113 LOG.debug("doLoad {}", file);
116 Object data = deserialize(file);
118 LOG.debug("deserialized data: {}", data);
120 return Optional.of(new SelectedSnapshot(metadata, data));
121 } catch (IOException e) {
122 LOG.error("Error loading snapshot file {}, remaining attempts: {}", file, metadatas.size(), e);
124 if (metadatas.isEmpty()) {
128 return doLoad(metadatas);
132 private Object deserialize(File file) throws IOException {
133 try (ObjectInputStream in = new ObjectInputStream(new FileInputStream(file))) {
134 return in.readObject();
135 } catch (ClassNotFoundException e) {
136 throw new IOException("Error loading snapshot file " + file, e);
137 } catch (IOException e) {
138 LOG.debug("Error loading snapshot file {}", file, e);
140 return tryDeserializeAkkaSnapshot(file);
144 private Object tryDeserializeAkkaSnapshot(File file) throws IOException {
145 LOG.debug("tryDeserializeAkkaSnapshot {}", file);
147 // The snapshot was probably previously stored via akka's LocalSnapshotStore which wraps the data
148 // in a Snapshot instance and uses the SnapshotSerializer to serialize it to a byte[]. So we'll use
149 // the SnapshotSerializer to try to de-serialize it.
151 SnapshotSerializer snapshotSerializer = new SnapshotSerializer((ExtendedActorSystem) context().system());
153 try (InputStream in = new BufferedInputStream(new FileInputStream(file))) {
154 return ((Snapshot)snapshotSerializer.fromBinary(ByteStreams.toByteArray(in))).data();
159 public Future<Void> doSaveAsync(SnapshotMetadata metadata, Object snapshot) {
160 LOG.debug("In doSaveAsync - metadata: {}, snapshot: {}", metadata, snapshot);
162 return Futures.future(() -> doSave(metadata, snapshot), executionContext);
165 private Void doSave(SnapshotMetadata metadata, Object snapshot) throws IOException {
166 File temp = toSnapshotFile(metadata, ".tmp");
168 LOG.debug("Saving to temp file: {}", temp);
170 try (ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(temp))) {
171 out.writeObject(snapshot);
172 } catch (IOException e) {
173 LOG.error("Error saving snapshot file {}", temp, e);
177 File actual = toSnapshotFile(metadata, "");
179 LOG.debug("Renaming to: {}", actual);
181 if (!temp.renameTo(actual)) {
182 throw new IOException(String.format("Failed to rename %s to %s", temp, actual));
189 public Future<Void> doDeleteAsync(SnapshotMetadata metadata) {
190 LOG.debug("In doDeleteAsync - metadata: {}", metadata);
192 // Multiple snapshot files here mean that there were multiple snapshots for this seqNr - we delete all of them.
193 // Usually snapshot-stores would keep one snapshot per sequenceNr however here in the file-based one we
194 // timestamp snapshots and allow multiple to be kept around (for the same seqNr) if desired.
196 return Futures.future(() -> doDelete(metadata), executionContext);
200 public Future<Void> doDeleteAsync(String persistenceId, SnapshotSelectionCriteria criteria) {
201 LOG.debug("In doDeleteAsync - persistenceId: {}, criteria: {}", persistenceId, criteria);
203 return Futures.future(() -> doDelete(persistenceId, criteria), executionContext);
206 private Void doDelete(String persistenceId, SnapshotSelectionCriteria criteria) {
207 final List<File> files = getSnapshotMetadatas(persistenceId, criteria).stream()
208 .flatMap(md -> Stream.of(toSnapshotFile(md, ""))).collect(Collectors.toList());
210 LOG.debug("Deleting files: {}", files);
212 files.forEach(file -> file.delete());
216 private Void doDelete(SnapshotMetadata metadata) {
217 final Collection<File> files = getSnapshotFiles(metadata);
219 LOG.debug("Deleting files: {}", files);
221 files.forEach(file -> file.delete());
225 private Collection<File> getSnapshotFiles(String persistenceId) {
226 String encodedPersistenceId = encode(persistenceId);
228 File[] files = snapshotDir.listFiles((FilenameFilter) (dir, name) -> {
229 int persistenceIdEndIndex = name.lastIndexOf('-', name.lastIndexOf('-') - 1);
230 return PERSISTENCE_ID_START_INDEX + encodedPersistenceId.length() == persistenceIdEndIndex
231 && name.startsWith(encodedPersistenceId, PERSISTENCE_ID_START_INDEX) && !name.endsWith(".tmp");
235 return Collections.emptyList();
238 if (LOG.isDebugEnabled()) {
239 LOG.debug("getSnapshotFiles for persistenceId: {}, found files: {}", encodedPersistenceId,
240 Arrays.toString(files));
243 return Arrays.asList(files);
246 private Collection<File> getSnapshotFiles(SnapshotMetadata metadata) {
247 return getSnapshotFiles(metadata.persistenceId()).stream().filter(file -> {
248 SnapshotMetadata possible = extractMetadata(file);
249 return possible != null && possible.sequenceNr() == metadata.sequenceNr()
250 && (metadata.timestamp() == 0L || possible.timestamp() == metadata.timestamp());
251 }).collect(Collectors.toList());
254 private Collection<SnapshotMetadata> getSnapshotMetadatas(String persistenceId,
255 SnapshotSelectionCriteria criteria) {
256 return getSnapshotFiles(persistenceId).stream().flatMap(file -> toStream(extractMetadata(file)))
257 .filter(md -> criteria.matches(md)).collect(Collectors.toList());
260 private static Stream<SnapshotMetadata> toStream(@Nullable SnapshotMetadata md) {
261 return md != null ? Stream.of(md) : Stream.empty();
265 private static SnapshotMetadata extractMetadata(File file) {
266 String name = file.getName();
267 int sequenceNumberEndIndex = name.lastIndexOf('-');
268 int persistenceIdEndIndex = name.lastIndexOf('-', sequenceNumberEndIndex - 1);
269 if (PERSISTENCE_ID_START_INDEX >= persistenceIdEndIndex) {
274 String persistenceId = name.substring(PERSISTENCE_ID_START_INDEX, persistenceIdEndIndex);
275 long sequenceNumber = Long.parseLong(name.substring(persistenceIdEndIndex + 1, sequenceNumberEndIndex));
276 long timestamp = Long.parseLong(name.substring(sequenceNumberEndIndex + 1));
277 return new SnapshotMetadata(persistenceId, sequenceNumber, timestamp);
278 } catch (NumberFormatException e) {
283 private File toSnapshotFile(SnapshotMetadata metadata, String extension) {
284 return new File(snapshotDir, String.format("snapshot-%s-%d-%d%s", encode(metadata.persistenceId()),
285 metadata.sequenceNr(), metadata.timestamp(), extension));
288 private static <T> Collector<T, ?, List<T>> reverse() {
289 return Collectors.collectingAndThen(Collectors.toList(), list -> {
290 Collections.reverse(list);
295 private String encode(String str) {
297 return URLEncoder.encode(str, StandardCharsets.UTF_8.name());
298 } catch (UnsupportedEncodingException e) {
300 LOG.warn("Error encoding {}", str, e);
306 static int compare(SnapshotMetadata m1, SnapshotMetadata m2) {
307 return (int) (!m1.persistenceId().equals(m2.persistenceId())
308 ? m1.persistenceId().compareTo(m2.persistenceId()) :
309 m1.sequenceNr() != m2.sequenceNr() ? m1.sequenceNr() - m2.sequenceNr() :
310 m1.timestamp() != m2.timestamp() ? m1.timestamp() - m2.timestamp() : 0);