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/*
* 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.uima.ducc.database;
import java.io.File;
import java.io.FileInputStream;
import java.util.Properties;
import org.apache.uima.ducc.common.utils.DuccLogger;
import com.datastax.driver.core.BoundStatement;
import com.datastax.driver.core.Cluster;
import com.datastax.driver.core.Host;
import com.datastax.driver.core.Metadata;
import com.datastax.driver.core.PlainTextAuthProvider;
import com.datastax.driver.core.PreparedStatement;
import com.datastax.driver.core.ResultSet;
import com.datastax.driver.core.Session;
import com.datastax.driver.core.SimpleStatement;
import com.datastax.driver.core.policies.ConstantReconnectionPolicy;
import com.datastax.driver.core.policies.ReconnectionPolicy;
/**
* Provide a common point for contacting the db, acquiring sessions/handles to it, managing the db,
* closing, etc.
*/
public class DbManager
{
static final String URL_PROPERTY = "ducc.database.host";
private static String db_id = null;
private static String db_pw = null;
String dburl;
DuccLogger logger;
private Cluster cluster; // only one
private Session session; // only one - it's thread safe and manages a connection pool
public DbManager(String dburl, DuccLogger logger)
throws Exception
{
this.dburl = dburl;
this.logger = logger;
}
boolean checkForDatabase()
throws Exception
{
String methodName = "checkForDatabase";
logger.warn(methodName, null, "Not yet implemented.");
return true;
}
public void drop()
throws Exception
{
String methodName = "drop";
logger.warn(methodName, null, "Drop is not implemented yet.");
}
public synchronized DbHandle open()
throws Exception
{
if ( session == null ) {
session = cluster.connect();
session.execute(new SimpleStatement("USE " + DbCreate.DUCC_KEYSPACE));
}
return new DbHandle(this);
}
public synchronized void init()
throws Exception
{
String methodName = "init";
if ( cluster != null ) return; // already initialized
dbPassword(); // sets some private static login stuff.
// will throw sometims, so we can assume
// we're allowed to continue if control passes down.
PlainTextAuthProvider auth = new PlainTextAuthProvider(db_id, db_pw); // throws if no good
ReconnectionPolicy rp = new ConstantReconnectionPolicy(10000); // if we lose connection, keep trying every 10 seconds
cluster = Cluster.builder()
.withAuthProvider(auth)
.addContactPoint(dburl)
.withReconnectionPolicy(rp)
.build();
Metadata metadata = cluster.getMetadata();
logger.info(methodName, null, "Connected to cluster:", metadata.getClusterName());
for (Host host : metadata.getAllHosts()) {
logger.info(methodName, null, "Datatacenter:", host.getDatacenter(), "Host:", host.getAddress(), "Rack:", host.getRack());
}
}
public synchronized void shutdown()
{
String methodName = "closeDatabase";
logger.info(methodName, null, "Closing the database.");
if ( cluster != null ) cluster.close();
cluster = null;
session = null;
}
PreparedStatement prepare(String cql)
{
return session.prepare(cql);
}
void truncate(String table)
throws Exception
{
execute("TRUNCATE " + table);
}
String truncateText(String s)
{
String ret = s;
if ( ret.length() > 200 ) {
ret = s.substring(0, 200) + " ... ";
}
return ret;
}
ResultSet execute(String cql)
{
String methodName = "execute";
if ( logger.isDebug() ) {
logger.debug(methodName, null, "EXECUTE CQL:", cql);
} else {
logger.trace(methodName, null, "EXECUTE CQL:", truncateText(cql));
}
return session.execute(cql);
}
ResultSet execute(BoundStatement s)
{
return session.execute(s);
}
ResultSet execute(SimpleStatement s)
{
String methodName = "execute";
logger.trace(methodName, null, "EXECUTE STATEMENT:", truncateText(s.getQueryString()));
return session.execute(s);
}
static void dbPassword()
throws Exception
{
// If I can not read the superuser password I'll allow login as guest. If guest has been revokded
// that will be discovered later when I actually sign in.
File f = new File(System.getProperty("DUCC_HOME") + "/resources.private/" + DbCreate.PASSWORD_FILE);
if ( ! f.canRead() ) {
db_id = "guest";
db_pw = "guest";
return;
}
// If i can read the file that's supposed to have the super user password I'll do so. If not, or
// if there's no password there, tough luck Charlie.
db_id = "ducc";
Properties props = new Properties();
FileInputStream fis = new FileInputStream(f);
props.load(fis);
fis.close();
db_pw = props.getProperty(DbCreate.PASSWORD_KEY);
if ( db_pw == null ) {
throw new IllegalStateException("Cannot acquire the database password.");
}
}
public static void main(String[] args)
{
}
}
