/*
* Copyright © 2014 Cask Data, Inc.
*
* Licensed 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 co.cask.cdap.data2.transaction.queue.leveldb;
import co.cask.cdap.common.conf.CConfiguration;
import co.cask.cdap.common.queue.QueueName;
import co.cask.cdap.data.Namespace;
import co.cask.cdap.data2.datafabric.DefaultDatasetNamespace;
import co.cask.cdap.data2.dataset2.lib.table.leveldb.LevelDBOrderedTableService;
import co.cask.cdap.data2.transaction.queue.QueueAdmin;
import co.cask.cdap.data2.transaction.queue.QueueConstants;
import com.google.inject.Inject;
import com.google.inject.Singleton;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.net.URI;
import java.util.Map;
import java.util.Properties;
import static co.cask.cdap.data2.transaction.queue.QueueConstants.QueueType.QUEUE;
/**
* admin for queues in leveldb.
*/
@Singleton
public class LevelDBQueueAdmin implements QueueAdmin {
private static final Logger LOG = LoggerFactory.getLogger(LevelDBQueueAdmin.class);
private final String tableNamePrefix;
private final LevelDBOrderedTableService service;
@Inject
public LevelDBQueueAdmin(CConfiguration conf, LevelDBOrderedTableService service) {
this(conf, service, QUEUE);
}
protected LevelDBQueueAdmin(CConfiguration conf, LevelDBOrderedTableService service,
QueueConstants.QueueType type) {
this.service = service;
// todo: we have to do that because queues do not follow dataset semantic fully (yet)
String unqualifiedTableNamePrefix =
type == QUEUE ? QueueConstants.QUEUE_TABLE_PREFIX : QueueConstants.STREAM_TABLE_PREFIX;
this.tableNamePrefix = new DefaultDatasetNamespace(conf, Namespace.SYSTEM).namespace(unqualifiedTableNamePrefix);
}
/**
* This determines the actual table name from the table name prefix and the name of the queue.
* @param queueName The name of the queue.
* @return the full name of the table that holds this queue.
*/
public String getActualTableName(QueueName queueName) {
if (queueName.isQueue()) {
// <cdap namespace>.system.queue.<account>.<flow>
return getTableNameForFlow(queueName.getFirstComponent(), queueName.getSecondComponent());
} else {
throw new IllegalArgumentException("'" + queueName + "' is not a valid name for a queue.");
}
}
private String getTableNameForFlow(String app, String flow) {
return tableNamePrefix + "." + app + "." + flow;
}
/**
* This determines whether dropping a queue is supported (by dropping the queue's table).
*/
public boolean doDropTable(@SuppressWarnings("unused") QueueName queueName) {
// no-op because this would drop all tables for the flow
// todo: introduce a method dropAllFor(flow) or similar
return false;
}
/**
* This determines whether truncating a queue is supported (by truncating the queue's table).
*/
public boolean doTruncateTable(@SuppressWarnings("unused") QueueName queueName) {
// yes, this will truncate all queues of the flow. But it rarely makes sense to clear a single queue.
// todo: introduce a method truncateAllFor(flow) or similar, and set this to false
return true;
}
@Override
public boolean exists(@SuppressWarnings("unused") String name) {
try {
String actualTableName = getActualTableName(QueueName.from(URI.create(name)));
service.getTable(actualTableName);
return true;
} catch (Exception e) {
return false;
}
}
@Override
public void create(String name) throws Exception {
create(QueueName.from(URI.create(name)));
}
public void create(QueueName queueName) throws Exception {
String actualTableName = getActualTableName(queueName);
service.ensureTableExists(actualTableName);
}
@Override
public void create(String name, @SuppressWarnings("unused") Properties props) throws Exception {
create(name);
}
@Override
public void truncate(String name) throws Exception {
QueueName queueName = QueueName.from(URI.create(name));
// all queues for one flow are stored in same table, and we would clear all of them. this makes it optional.
if (doTruncateTable(queueName)) {
String actualTableName = getActualTableName(queueName);
service.dropTable(actualTableName);
service.ensureTableExists(actualTableName);
} else {
LOG.warn("truncate({}) on LevelDB queue table has no effect.", name);
}
}
@Override
public void clearAllForFlow(String app, String flow) throws Exception {
String tableName = getTableNameForFlow(app, flow);
service.dropTable(tableName);
service.ensureTableExists(tableName);
}
@Override
public void dropAllForFlow(String app, String flow) throws Exception {
String tableName = getTableNameForFlow(app, flow);
service.dropTable(tableName);
}
@Override
public void drop(String name) throws Exception {
QueueName queueName = QueueName.from(URI.create(name));
// all queues for one flow are stored in same table, and we would drop all of them. this makes it optional.
if (doDropTable(queueName)) {
String actualTableName = getActualTableName(queueName);
service.dropTable(actualTableName);
} else {
LOG.warn("drop({}) on LevelDB queue table has no effect.", name);
}
}
@Override
public void upgrade(String name, Properties properties) throws Exception {
// No-op
}
@Override
public void dropAll() throws Exception {
for (String tableName : service.list()) {
if (tableName.startsWith(tableNamePrefix)) {
service.dropTable(tableName);
}
}
}
@Override
public void configureInstances(QueueName queueName, long groupId, int instances) {
// No-op
// Potentially refactor QueueClientFactory to have better way to handle instances and group info.
}
@Override
public void configureGroups(QueueName queueName, Map<Long, Integer> groupInfo) {
// No-op
// Potentially refactor QueueClientFactory to have better way to handle instances and group info.
}
@Override
public void upgrade() throws Exception {
// No-op
}
protected String getTableNamePrefix() {
return tableNamePrefix;
}
}