/**
* 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.falcon.entity.store;
import org.apache.falcon.FalconException;
import org.apache.falcon.entity.v0.Entity;
import org.apache.falcon.entity.v0.EntityType;
import org.apache.falcon.hadoop.HadoopClientFactory;
import org.apache.falcon.service.ConfigurationChangeListener;
import org.apache.falcon.service.FalconService;
import org.apache.falcon.util.ReflectionUtils;
import org.apache.falcon.util.StartupProperties;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.permission.FsAction;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.log4j.Logger;
import javax.xml.bind.JAXBException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
/**
* Persistent store for falcon entities.
*/
public final class ConfigurationStore implements FalconService {
private static final Logger LOG = Logger.getLogger(ConfigurationStore.class);
private static final Logger AUDIT = Logger.getLogger("AUDIT");
private static final String UTF_8 = "UTF-8";
private static final ConfigurationStore STORE = new ConfigurationStore();
private Set<ConfigurationChangeListener> listeners = new LinkedHashSet<ConfigurationChangeListener>();
private ThreadLocal<Entity> updatesInProgress = new ThreadLocal<Entity>();
public static ConfigurationStore get() {
return STORE;
}
private final Map<EntityType, ConcurrentHashMap<String, Entity>> dictionary
= new HashMap<EntityType, ConcurrentHashMap<String, Entity>>();
private final FileSystem fs;
private final Path storePath;
private static final Entity NULL = new Entity() {
@Override
public String getName() {
return "NULL";
}
};
private ConfigurationStore() {
for (EntityType type : EntityType.values()) {
dictionary.put(type, new ConcurrentHashMap<String, Entity>());
}
String uri = StartupProperties.get().getProperty("config.store.uri");
storePath = new Path(uri);
fs = initializeFileSystem();
}
/**
* Falcon owns this dir on HDFS which no one has permissions to read.
*
* @return FileSystem handle
*/
private FileSystem initializeFileSystem() {
try {
FileSystem fileSystem = HadoopClientFactory.get().createFileSystem(storePath.toUri());
if (!fileSystem.exists(storePath)) {
LOG.info("Creating configuration store directory: " + storePath);
fileSystem.mkdirs(storePath);
// set permissions so config store dir is owned by falcon alone
FsPermission permission = new FsPermission(FsAction.ALL, FsAction.NONE, FsAction.NONE);
fileSystem.setPermission(storePath, permission);
}
return fileSystem;
} catch (Exception e) {
throw new RuntimeException("Unable to bring up config store", e);
}
}
@Override
public void init() throws FalconException {
String listenerClassNames = StartupProperties.get().
getProperty("configstore.listeners", "org.apache.falcon.entity.v0.EntityGraph");
for (String listenerClassName : listenerClassNames.split(",")) {
listenerClassName = listenerClassName.trim();
if (listenerClassName.isEmpty()) {
continue;
}
ConfigurationChangeListener listener = ReflectionUtils.getInstanceByClassName(listenerClassName);
registerListener(listener);
}
try {
for (EntityType type : EntityType.values()) {
ConcurrentHashMap<String, Entity> entityMap = dictionary.get(type);
FileStatus[] files = fs.globStatus(new Path(storePath, type.name() + Path.SEPARATOR + "*"));
if (files != null) {
for (FileStatus file : files) {
String fileName = file.getPath().getName();
String encodedEntityName = fileName.substring(0, fileName.length() - 4); // drop
// ".xml"
String entityName = URLDecoder.decode(encodedEntityName, UTF_8);
Entity entity = restore(type, entityName);
entityMap.put(entityName, entity);
onReload(entity);
}
}
}
} catch (IOException e) {
throw new FalconException("Unable to restore configurations", e);
}
}
public void registerListener(ConfigurationChangeListener listener) {
listeners.add(listener);
}
public void unregisterListener(ConfigurationChangeListener listener) {
listeners.remove(listener);
}
/**
* @param type - EntityType that need to be published
* @param entity - Reference to the Entity Object
* @throws FalconException
*/
public synchronized void publish(EntityType type, Entity entity) throws FalconException {
try {
if (get(type, entity.getName()) == null) {
persist(type, entity);
onAdd(entity);
dictionary.get(type).put(entity.getName(), entity);
} else {
throw new EntityAlreadyExistsException(
entity.toShortString() + " already registered with configuration store. "
+ "Can't be submitted again. Try removing before submitting.");
}
} catch (IOException e) {
throw new StoreAccessException(e);
}
AUDIT.info(type + "/" + entity.getName() + " is published into config store");
}
private synchronized void updateInternal(EntityType type, Entity entity) throws FalconException {
try {
if (get(type, entity.getName()) != null) {
persist(type, entity);
ConcurrentHashMap<String, Entity> entityMap = dictionary.get(type);
Entity oldEntity = entityMap.get(entity.getName());
onChange(oldEntity, entity);
entityMap.put(entity.getName(), entity);
} else {
throw new FalconException(entity.toShortString() + " doesn't exist");
}
} catch (IOException e) {
throw new StoreAccessException(e);
}
AUDIT.info(type + "/" + entity.getName() + " is replaced into config store");
}
public synchronized void update(EntityType type, Entity entity) throws FalconException {
if (updatesInProgress.get() == entity) {
updateInternal(type, entity);
} else {
throw new FalconException(entity.toShortString() + " is not initialized for update");
}
}
private void onAdd(Entity entity) throws FalconException {
for (ConfigurationChangeListener listener : listeners) {
listener.onAdd(entity);
}
}
private void onChange(Entity oldEntity, Entity newEntity) throws FalconException {
for (ConfigurationChangeListener listener : listeners) {
listener.onChange(oldEntity, newEntity);
}
}
private void onReload(Entity entity) throws FalconException {
for (ConfigurationChangeListener listener : listeners) {
listener.onReload(entity);
}
}
public synchronized void initiateUpdate(Entity entity) throws FalconException {
if (get(entity.getEntityType(), entity.getName()) == null || updatesInProgress.get() != null) {
throw new FalconException(
"An update for " + entity.toShortString() + " is already in progress or doesn't exist");
}
updatesInProgress.set(entity);
}
/**
* @param type - Entity type that is being retrieved
* @param name - Name as it appears in the entity xml definition
* @param <T> - Actual Entity object type
* @return - Entity object from internal dictionary, If the object is not
* loaded in memory yet, it will retrieve it from persistent store
* just in time. On startup all the entities will be added to the
* dictionary with null reference.
* @throws FalconException
*/
@SuppressWarnings("unchecked")
public <T extends Entity> T get(EntityType type, String name) throws FalconException {
ConcurrentHashMap<String, Entity> entityMap = dictionary.get(type);
if (entityMap.containsKey(name)) {
if (updatesInProgress.get() != null && updatesInProgress.get().getEntityType() == type
&& updatesInProgress.get().getName().equals(name)) {
return (T) updatesInProgress.get();
}
T entity = (T) entityMap.get(name);
if (entity == NULL) { // Object equality being checked
try {
entity = this.restore(type, name);
} catch (IOException e) {
throw new StoreAccessException(e);
}
entityMap.put(name, entity);
return entity;
} else {
return entity;
}
} else {
return null;
}
}
public Collection<String> getEntities(EntityType type) {
return Collections.unmodifiableCollection(dictionary.get(type).keySet());
}
/**
* Remove an entity which is already stored in the config store.
*
* @param type - Entity type being removed
* @param name - Name of the entity object being removed
* @return - True is remove is successful, false if request entity doesn't
* exist
* @throws FalconException
*/
public boolean remove(EntityType type, String name) throws FalconException {
Map<String, Entity> entityMap = dictionary.get(type);
if (entityMap.containsKey(name)) {
try {
archive(type, name);
Entity entity = entityMap.get(name);
onRemove(entity);
entityMap.remove(name);
} catch (IOException e) {
throw new StoreAccessException(e);
}
AUDIT.info(type + " " + name + " is removed from config store");
return true;
}
return false;
}
private void onRemove(Entity entity) throws FalconException {
for (ConfigurationChangeListener listener : listeners) {
listener.onRemove(entity);
}
}
/**
* @param type - Entity type that is to be stored into persistent storage
* @param entity - entity to persist. JAXB Annotated entity will be marshalled
* to the persistent store. The convention used for storing the
* object:: PROP(config.store.uri)/{entitytype}/{entityname}.xml
* @throws java.io.IOException If any error in accessing the storage
* @throws FalconException
*/
private void persist(EntityType type, Entity entity) throws IOException, FalconException {
OutputStream out = fs
.create(new Path(storePath,
type + Path.SEPARATOR + URLEncoder.encode(entity.getName(), UTF_8) + ".xml"));
try {
type.getMarshaller().marshal(entity, out);
LOG.info("Persisted configuration " + type + "/" + entity.getName());
} catch (JAXBException e) {
LOG.error(e);
throw new StoreAccessException("Unable to serialize the entity object " + type + "/" + entity.getName(), e);
} finally {
out.close();
}
}
/**
* Archive removed configuration in the persistent store.
*
* @param type - Entity type to archive
* @param name - name
* @throws IOException If any error in accessing the storage
*/
private void archive(EntityType type, String name) throws IOException {
Path archivePath = new Path(storePath, "archive" + Path.SEPARATOR + type);
fs.mkdirs(archivePath);
fs.rename(new Path(storePath, type + Path.SEPARATOR + URLEncoder.encode(name, UTF_8) + ".xml"),
new Path(archivePath, URLEncoder.encode(name, UTF_8) + "." + System.currentTimeMillis()));
LOG.info("Archived configuration " + type + "/" + name);
}
/**
* @param type - Entity type to restore from persistent store
* @param name - Name of the entity to restore.
* @param <T> - Actual entity object type
* @return - De-serialized entity object restored from persistent store
* @throws IOException If any error in accessing the storage
* @throws FalconException
*/
@SuppressWarnings("unchecked")
private synchronized <T extends Entity> T restore(EntityType type, String name)
throws IOException, FalconException {
InputStream in = fs.open(new Path(storePath, type + Path.SEPARATOR + URLEncoder.encode(name, UTF_8) + ".xml"));
try {
return (T) type.getUnmarshaller().unmarshal(in);
} catch (JAXBException e) {
throw new StoreAccessException("Unable to un-marshall xml definition for " + type + "/" + name, e);
} finally {
in.close();
LOG.info("Restored configuration " + type + "/" + name);
}
}
public void cleanupUpdateInit() {
updatesInProgress.set(null);
}
@Override
public String getName() {
return this.getClass().getName();
}
@Override
public void destroy() {
}
}