private void pingSessionBackup(@Nonnull final MemcachedBackupSession session)
throws InterruptedException {
final String key = _sessionIdFormat.createBackupKey(session.getId());
final Future<Boolean> touchResultFuture = _memcached.add(key, 5, 1);
try {
final boolean touchResult =
touchResultFuture.get(_manager.getOperationTimeout(), TimeUnit.MILLISECONDS);
if (touchResult) {
_log.warn(
"The secondary backup for session "
+ session.getIdInternal()
+ " should be touched in memcached, but it seemed to be"
+ " not existing. Will store in memcached again.");
saveSessionBackup(session, key);
} else _log.debug("The secondary session backup was ping'ed successfully.");
} catch (final TimeoutException e) {
_log.warn(
"The secondary backup for session "
+ session.getIdInternal()
+ " could not be completed within "
+ _manager.getOperationTimeout()
+ " millis, was cancelled now.");
} catch (final ExecutionException e) {
_log.warn(
"An exception occurred when trying to ping session " + session.getIdInternal(), e);
}
}
@Override
public Void call() throws Exception {
final BackupResult backupResult = _result.get();
if (_pingSessionIfBackupWasSkipped) {
if (backupResult.getStatus() == BackupResultStatus.SKIPPED) {
pingSession(_session, _backupSessionService);
}
}
/*
* For non-sticky sessions we store a backup of the session in a secondary memcached node (under a special key
* that's resolved by the SuffixBasedNodeLocator), but only when we have more than 1 memcached node configured...
*/
if (_storeSecondaryBackup) {
try {
if (_log.isDebugEnabled()) {
_log.debug(
"Storing backup in secondary memcached for non-sticky session " + _session.getId());
}
if (backupResult.getStatus() == BackupResultStatus.SKIPPED) {
pingSessionBackup(_session);
} else {
saveSessionBackupFromResult(backupResult);
}
saveValidityBackup();
} catch (final RuntimeException e) {
_log.info("Could not store secondary backup of session " + _session.getIdInternal(), e);
}
}
return null;
}
/**
* Invoked after a non-sticky session is loaded from memcached, can be used to update some session
* fields based on separately stored information (e.g. session validity info).
*
* @param lockStatus the {@link LockStatus} that was returned from {@link
* #onBeforeLoadFromMemcached(String)}.
*/
protected void onAfterLoadFromMemcached(
@Nonnull final MemcachedBackupSession session, @Nullable final LockStatus lockStatus) {
session.setLockStatus(lockStatus);
final long start = System.currentTimeMillis();
final SessionValidityInfo info = loadSessionValidityInfo(session.getIdInternal());
if (info != null) {
_stats.registerSince(NON_STICKY_AFTER_LOAD_FROM_MEMCACHED, start);
session.setLastAccessedTimeInternal(info.getLastAccessedTime());
session.setThisAccessedTimeInternal(info.getThisAccessedTime());
} else {
_log.warn("No validity info available for session " + session.getIdInternal());
}
}
public void saveValidityBackup() {
final String backupValidityKey = _sessionIdFormat.createBackupKey(_validityKey);
final int maxInactiveInterval = _session.getMaxInactiveInterval();
// fix for #88, along with the change in session.getMemcachedExpirationTimeToSet
final int expiration = maxInactiveInterval <= 0 ? 0 : maxInactiveInterval;
_memcached.set(backupValidityKey, toMemcachedExpiration(expiration), _validityData);
}
public void saveSessionBackupFromResult(final BackupResult backupResult) {
final byte[] data = backupResult.getData();
if (data != null) {
final String key = _sessionIdFormat.createBackupKey(_session.getId());
_memcached.set(
key, toMemcachedExpiration(_session.getMemcachedExpirationTimeToSet()), data);
} else {
_log.warn(
"No data set for backupResultStatus "
+ backupResult.getStatus()
+ " for sessionId "
+ _session.getIdInternal()
+ ", skipping backup"
+ " of non-sticky session in secondary memcached.");
}
}
private void pingSession(
@Nonnull final MemcachedBackupSession session,
@Nonnull final BackupSessionService backupSessionService)
throws InterruptedException {
final Future<Boolean> touchResult =
_memcached.add(_storageKeyFormat.format(session.getIdInternal()), 5, 1);
try {
if (touchResult.get()) {
_stats.nonStickySessionsPingFailed();
_log.warn(
"The session "
+ session.getIdInternal()
+ " should be touched in memcached, but it does not exist"
+ " therein. Will store in memcached again.");
updateSession(session, backupSessionService);
} else _log.debug("The session was ping'ed successfully.");
} catch (final ExecutionException e) {
_log.warn("An exception occurred when trying to ping session " + session.getIdInternal(), e);
}
}
public void saveSessionBackup(
@Nonnull final MemcachedBackupSession session, @Nonnull final String key)
throws InterruptedException {
try {
final byte[] data = _manager.serialize(session);
final Future<Boolean> backupResult =
_memcached.set(
key, toMemcachedExpiration(session.getMemcachedExpirationTimeToSet()), data);
if (!backupResult.get().booleanValue()) {
_log.warn(
"Update for secondary backup of session "
+ session.getIdInternal()
+ " (after unsuccessful ping) did not return sucess.");
}
} catch (final ExecutionException e) {
_log.warn(
"An exception occurred when trying to update secondary session backup for "
+ session.getIdInternal(),
e);
}
}
/**
* Deserialize session data that was serialized using {@link #serialize(MemcachedBackupSession)}
* (or a combination of {@link #serializeAttributes(MemcachedBackupSession, Map)} and {@link
* #serialize(MemcachedBackupSession, byte[])}).
*
* <p>Note: the returned session already has the manager set and {@link
* MemcachedBackupSession#doAfterDeserialization()} is invoked. Additionally the attributes hash
* is set (via {@link MemcachedBackupSession#setDataHashCode(int)}).
*
* @param data the byte array of the serialized session and its session attributes. Can be <code>
* null</code>.
* @param realm the realm that is used to reconstruct the principal if there was any stored in the
* session.
* @param manager the manager to set on the deserialized session.
* @return the deserialized {@link MemcachedBackupSession} or <code>null</code> if the provided
* <code>byte[] data</code> was <code>null</code>.
*/
public MemcachedBackupSession deserialize(final byte[] data, final SessionManager manager) {
if (data == null) {
return null;
}
try {
final DeserializationResult deserializationResult = deserializeSessionFields(data, manager);
final byte[] attributesData = deserializationResult.getAttributesData();
final Map<String, Object> attributes = deserializeAttributes(attributesData);
final MemcachedBackupSession session = deserializationResult.getSession();
session.setAttributesInternal(attributes);
session.setDataHashCode(Arrays.hashCode(attributesData));
session.setManager(manager);
session.doAfterDeserialization();
return session;
} catch (final InvalidVersionException e) {
LOG.info("Got session data from memcached with an unsupported version: " + e.getVersion());
// for versioning probably there will be changes in the design,
// with the first change and version 2 we'll see what we need
return null;
}
}
private void updateSession(
@Nonnull final MemcachedBackupSession session,
@Nonnull final BackupSessionService backupSessionService)
throws InterruptedException {
final Future<BackupResult> result = backupSessionService.backupSession(session, true);
try {
if (result.get().getStatus() != BackupResultStatus.SUCCESS) {
_log.warn(
"Update for session (after unsuccessful ping) did not return SUCCESS, but "
+ result.get());
}
} catch (final ExecutionException e) {
_log.warn(
"An exception occurred when trying to update session " + session.getIdInternal(), e);
}
}
/**
* Is invoked after the backup of the session is initiated, it's represented by the provided
* backupResult. The requestId is identifying the request.
*/
protected void onAfterBackupSession(
@Nonnull final MemcachedBackupSession session,
final boolean backupWasForced,
@Nonnull final Future<BackupResult> result,
@Nonnull final String requestId,
@Nonnull final BackupSessionService backupSessionService) {
if (!_sessionIdFormat.isValid(session.getIdInternal())) {
return;
}
try {
final long start = System.currentTimeMillis();
final int maxInactiveInterval = session.getMaxInactiveInterval();
final byte[] validityData =
encode(
maxInactiveInterval,
session.getLastAccessedTimeInternal(),
session.getThisAccessedTimeInternal());
final String validityKey =
_sessionIdFormat.createValidityInfoKeyName(session.getIdInternal());
// fix for #88, along with the change in session.getMemcachedExpirationTimeToSet
final int expiration = maxInactiveInterval <= 0 ? 0 : maxInactiveInterval;
final Future<Boolean> validityResult =
_memcached.set(validityKey, toMemcachedExpiration(expiration), validityData);
if (!_manager.isSessionBackupAsync()) {
// TODO: together with session backup wait not longer than sessionBackupTimeout.
// Details: Now/here we're waiting the whole session backup timeout, even if (perhaps) some
// time
// was spent before when waiting for session backup result.
// For sync session backup it would be better to set both the session data and
// validity info and afterwards wait for both results (but in sum no longer than
// sessionBackupTimeout)
validityResult.get(_manager.getSessionBackupTimeout(), TimeUnit.MILLISECONDS);
}
if (_log.isDebugEnabled()) {
_log.debug("Stored session validity info for session " + session.getIdInternal());
}
/* The following task are performed outside of the request thread (includes waiting for the backup result):
* - ping session if the backup was skipped (depends on the backup result)
* - save secondary session backup if session was modified (backup not skipped)
* - ping secondary session backup if the backup was skipped
* - save secondary validity backup
*/
final boolean pingSessionIfBackupWasSkipped = !backupWasForced;
final boolean performAsyncTasks = pingSessionIfBackupWasSkipped || _storeSecondaryBackup;
if (performAsyncTasks) {
final Callable<?> backupSessionTask =
new OnAfterBackupSessionTask(
session,
result,
pingSessionIfBackupWasSkipped,
backupSessionService,
_storeSecondaryBackup,
validityKey,
validityData);
_executor.submit(backupSessionTask);
}
_stats.registerSince(NON_STICKY_AFTER_BACKUP, start);
} catch (final Throwable e) {
_log.warn("An error occurred during onAfterBackupSession.", e);
}
}
/**
* Serialize the given session to a byte array. This is a shortcut for <code><pre>
* final byte[] attributesData = serializeAttributes( session, session.getAttributes() );
* serialize( session, attributesData );
* </pre></code> The returned byte array can be deserialized using {@link #deserialize(byte[],
* Realm, Manager)}.
*
* @see #serializeAttributes(MemcachedBackupSession, Map)
* @see #serialize(MemcachedBackupSession, byte[])
* @see #deserialize(byte[], Realm, Manager)
* @param session the session to serialize.
* @return the serialized session data.
*/
public byte[] serialize(final MemcachedBackupSession session) {
final byte[] attributesData = serializeAttributes(session, session.getAttributesInternal());
return serialize(session, attributesData);
}
static DeserializationResult deserializeSessionFields(
final byte[] data, final SessionManager manager) throws InvalidVersionException {
final MemcachedBackupSession result = manager.newMemcachedBackupSession();
final short version = (short) decodeNum(data, 0, 2);
if (version != CURRENT_VERSION) {
throw new InvalidVersionException(
"The version " + version + " does not match the current version " + CURRENT_VERSION,
version);
}
final short sessionFieldsDataLength = (short) decodeNum(data, 2, 2);
result.setCreationTimeInternal(decodeNum(data, 4, 8));
result.setLastAccessedTimeInternal(decodeNum(data, 12, 8));
result.setMaxInactiveInterval((int) decodeNum(data, 20, 4));
result.setIsNewInternal(decodeBoolean(data, 24));
result.setIsValidInternal(decodeBoolean(data, 25));
result.setThisAccessedTimeInternal(decodeNum(data, 26, 8));
result.setLastBackupTime(decodeNum(data, 34, 8));
final short idLength = (short) decodeNum(data, 42, 2);
result.setIdInternal(decodeString(data, 44, idLength));
final short authTypeId = (short) decodeNum(data, 44 + idLength, 2);
result.setAuthTypeInternal(AuthType.valueOfId(authTypeId).getValue());
final int currentIdx = 44 + idLength + 2;
final short principalDataLength = (short) decodeNum(data, currentIdx, 2);
if (principalDataLength > 0) {
final byte[] principalData = new byte[principalDataLength];
System.arraycopy(data, currentIdx + 2, principalData, 0, principalDataLength);
result.setPrincipalInternal(deserializePrincipal(principalData, manager));
}
final byte[] attributesData = new byte[data.length - sessionFieldsDataLength];
System.arraycopy(
data, sessionFieldsDataLength, attributesData, 0, data.length - sessionFieldsDataLength);
return new DeserializationResult(result, attributesData);
}
static byte[] serializeSessionFields(final MemcachedBackupSession session) {
final byte[] idData = serializeId(session.getIdInternal());
final byte[] principalData =
session.getPrincipal() != null ? serializePrincipal(session.getPrincipal()) : null;
final int principalDataLength = principalData != null ? principalData.length : 0;
final int sessionFieldsDataLength =
2 // short value for the version
// the following might change with other versions, refactoring needed then
+ 2 // short value that stores the dataLength
+ NUM_BYTES // bytes that store all session attributes but the id
+ 2 // short value that stores the idData length
+ idData.length // the number of bytes for the id
+ 2 // short value for the authType
+ 2 // short value that stores the principalData length
+ principalDataLength; // the number of bytes for the principal
final byte[] data = new byte[sessionFieldsDataLength];
int idx = 0;
idx = encodeNum(CURRENT_VERSION, data, idx, 2);
idx = encodeNum(sessionFieldsDataLength, data, idx, 2);
idx = encodeNum(session.getCreationTimeInternal(), data, idx, 8);
idx = encodeNum(session.getLastAccessedTimeInternal(), data, idx, 8);
idx = encodeNum(session.getMaxInactiveInterval(), data, idx, 4);
idx = encodeBoolean(session.isNewInternal(), data, idx);
idx = encodeBoolean(session.isValidInternal(), data, idx);
idx = encodeNum(session.getThisAccessedTimeInternal(), data, idx, 8);
idx = encodeNum(session.getLastBackupTime(), data, idx, 8);
idx = encodeNum(idData.length, data, idx, 2);
idx = copy(idData, data, idx);
idx = encodeNum(AuthType.valueOfValue(session.getAuthType()).getId(), data, idx, 2);
idx = encodeNum(principalDataLength, data, idx, 2);
copy(principalData, data, idx);
return data;
}
