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co.cask.hydrator.plugin.DBUtils Maven / Gradle / Ivy
/*
* Copyright © 2015 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.hydrator.plugin;
import co.cask.cdap.api.data.schema.Schema;
import co.cask.cdap.api.data.schema.UnsupportedTypeException;
import com.google.common.base.Strings;
import com.google.common.collect.Lists;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.lang.management.ManagementFactory;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.math.BigDecimal;
import java.sql.Blob;
import java.sql.Clob;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Types;
import java.util.Hashtable;
import java.util.List;
import javax.annotation.Nullable;
import javax.management.InstanceNotFoundException;
import javax.management.IntrospectionException;
import javax.management.MBeanRegistrationException;
import javax.management.MBeanServer;
import javax.management.MalformedObjectNameException;
import javax.management.ObjectName;
import javax.management.ReflectionException;
/**
* Utility methods for Database plugins shared by Database plugins.
*/
public final class DBUtils {
private static final Logger LOG = LoggerFactory.getLogger(DBUtils.class);
public static final String OVERRIDE_SCHEMA = "co.cask.hydrator.db.override.schema";
/**
* Performs any Database related cleanup
*
* @param driverClass the JDBC driver class
*/
public static void cleanup(Class driverClass) {
ClassLoader pluginClassLoader = driverClass.getClassLoader();
if (pluginClassLoader == null) {
// This could only be null if the classLoader is the Bootstrap/Primordial classloader. This should never be the
// case since the driver class is always loaded from the plugin classloader.
LOG.warn("PluginClassLoader is null. Cleanup not necessary.");
return;
}
shutDownMySQLAbandonedConnectionCleanupThread(pluginClassLoader);
unregisterOracleMBean(pluginClassLoader);
}
/**
* Ensures that the JDBC Driver specified in configuration is available and can be loaded. Also registers it with
* {@link DriverManager} if it is not already registered.
*/
public static DriverCleanup ensureJDBCDriverIsAvailable(Class jdbcDriverClass,
String connectionString,
String jdbcPluginType, String jdbcPluginName)
throws IllegalAccessException, InstantiationException, SQLException {
try {
DriverManager.getDriver(connectionString);
return new DriverCleanup(null);
} catch (SQLException e) {
// Driver not found. We will try to register it with the DriverManager.
LOG.debug("Plugin Type: {} and Plugin Name: {}; Driver Class: {} not found. Registering JDBC driver via shim {} ",
jdbcPluginType, jdbcPluginName, jdbcDriverClass.getName(),
JDBCDriverShim.class.getName());
final JDBCDriverShim driverShim = new JDBCDriverShim(jdbcDriverClass.newInstance());
try {
DBUtils.deregisterAllDrivers(jdbcDriverClass);
} catch (NoSuchFieldException | ClassNotFoundException e1) {
LOG.error("Unable to deregister JDBC Driver class {}", jdbcDriverClass);
}
DriverManager.registerDriver(driverShim);
return new DriverCleanup(driverShim);
}
}
/**
* Given the result set, get the metadata of the result set and return
* list of {@link co.cask.cdap.api.data.schema.Schema.Field},
* where name of the field is same as column name and type of the field is obtained using
* {@link DBUtils#getType(int, int, int)}
*
* @param resultSet result set of executed query
* @param schemaStr schema string to override resultant schema
* @return list of schema fields
* @throws SQLException
* @throws IOException
*/
public static List getSchemaFields(ResultSet resultSet, @Nullable String schemaStr)
throws SQLException {
Schema resultsetSchema = Schema.recordOf("resultset", getSchemaFields(resultSet));
Schema schema;
if (!Strings.isNullOrEmpty(schemaStr)) {
try {
schema = Schema.parseJson(schemaStr);
} catch (IOException e) {
throw new IllegalArgumentException(String.format("Unable to parse schema string %s", schemaStr), e);
}
for (Schema.Field field : schema.getFields()) {
Schema.Field resultsetField = resultsetSchema.getField(field.getName());
if (resultsetField == null) {
throw new IllegalArgumentException(String.format("Schema field %s is not present in input record",
field.getName()));
}
Schema resultsetFieldSchema = resultsetField.getSchema().isNullable() ?
resultsetField.getSchema().getNonNullable() : resultsetField.getSchema();
Schema simpleSchema = field.getSchema().isNullable() ? field.getSchema().getNonNullable() : field.getSchema();
if (!resultsetFieldSchema.equals(simpleSchema)) {
throw new IllegalArgumentException(String.format("Schema field %s has type %s but in input record found " +
"type %s ",
field.getName(), simpleSchema.getType(),
resultsetFieldSchema.getType()));
}
}
return schema.getFields();
}
return resultsetSchema.getFields();
}
/**
* Given the result set, get the metadata of the result set and return
* list of {@link co.cask.cdap.api.data.schema.Schema.Field},
* where name of the field is same as column name and type of the field is obtained using
* {@link DBUtils#getType(int, int, int)}
*
* @param resultSet result set of executed query
* @return list of schema fields
* @throws SQLException
*/
public static List getSchemaFields(ResultSet resultSet) throws SQLException {
List schemaFields = Lists.newArrayList();
ResultSetMetaData metadata = resultSet.getMetaData();
// ResultSetMetadata columns are numbered starting with 1
for (int i = 1; i <= metadata.getColumnCount(); i++) {
String columnName = metadata.getColumnName(i);
int columnSqlType = metadata.getColumnType(i);
int columnSqlPrecision = metadata.getPrecision(i); // total number of digits
int columnSqlScale = metadata.getScale(i); // digits after the decimal point
Schema columnSchema = Schema.of(getType(columnSqlType, columnSqlPrecision, columnSqlScale));
if (ResultSetMetaData.columnNullable == metadata.isNullable(i)) {
columnSchema = Schema.nullableOf(columnSchema);
}
Schema.Field field = Schema.Field.of(columnName, columnSchema);
schemaFields.add(field);
}
return schemaFields;
}
// given a sql type return schema type
private static Schema.Type getType(int sqlType, int precision, int scale) throws SQLException {
// Type.STRING covers sql types - VARCHAR,CHAR,CLOB,LONGNVARCHAR,LONGVARCHAR,NCHAR,NCLOB,NVARCHAR
Schema.Type type = Schema.Type.STRING;
switch (sqlType) {
case Types.NULL:
type = Schema.Type.NULL;
break;
case Types.ROWID:
break;
case Types.BOOLEAN:
case Types.BIT:
type = Schema.Type.BOOLEAN;
break;
case Types.TINYINT:
case Types.SMALLINT:
case Types.INTEGER:
type = Schema.Type.INT;
break;
case Types.BIGINT:
type = Schema.Type.LONG;
break;
case Types.REAL:
case Types.FLOAT:
type = Schema.Type.FLOAT;
break;
case Types.NUMERIC:
case Types.DECIMAL:
// if there are no digits after the point, use integer types
type = scale != 0 ? Schema.Type.DOUBLE :
// with 10 digits we can represent 2^32 and LONG is required
precision > 9 ? Schema.Type.LONG : Schema.Type.INT;
break;
case Types.DOUBLE:
type = Schema.Type.DOUBLE;
break;
case Types.DATE:
case Types.TIME:
case Types.TIMESTAMP:
type = Schema.Type.LONG;
break;
case Types.BINARY:
case Types.VARBINARY:
case Types.LONGVARBINARY:
case Types.BLOB:
type = Schema.Type.BYTES;
break;
case Types.ARRAY:
case Types.DATALINK:
case Types.DISTINCT:
case Types.JAVA_OBJECT:
case Types.OTHER:
case Types.REF:
case Types.SQLXML:
case Types.STRUCT:
throw new SQLException(new UnsupportedTypeException("Unsupported SQL Type: " + sqlType));
}
return type;
}
@Nullable
public static Object transformValue(int sqlType, int precision, int scale,
ResultSet resultSet, String fieldName) throws SQLException {
Object original = resultSet.getObject(fieldName);
if (original != null) {
switch (sqlType) {
case Types.SMALLINT:
case Types.TINYINT:
return ((Number) original).intValue();
case Types.NUMERIC:
case Types.DECIMAL:
BigDecimal decimal = (BigDecimal) original;
if (scale != 0) {
// if there are digits after the point, use double types
return decimal.doubleValue();
} else if (precision > 9) {
// with 10 digits we can represent 2^32 and LONG is required
return decimal.longValue();
} else {
return decimal.intValue();
}
case Types.DATE:
return resultSet.getDate(fieldName).getTime();
case Types.TIME:
return resultSet.getTime(fieldName).getTime();
case Types.TIMESTAMP:
return resultSet.getTimestamp(fieldName).getTime();
case Types.ROWID:
return resultSet.getString(fieldName);
case Types.BLOB:
Blob blob = (Blob) original;
try {
return blob.getBytes(1, (int) blob.length());
} finally {
blob.free();
}
case Types.CLOB:
Clob clob = (Clob) original;
try {
return clob.getSubString(1, (int) clob.length());
} finally {
clob.free();
}
}
}
return original;
}
/**
* De-register all SQL drivers that are associated with the class
*/
public static void deregisterAllDrivers(Class driverClass)
throws NoSuchFieldException, IllegalAccessException, ClassNotFoundException {
Field field = DriverManager.class.getDeclaredField("registeredDrivers");
field.setAccessible(true);
List list = (List) field.get(null);
for (Object driverInfo : list) {
Class driverInfoClass = DBUtils.class.getClassLoader().loadClass("java.sql.DriverInfo");
Field driverField = driverInfoClass.getDeclaredField("driver");
driverField.setAccessible(true);
Driver d = (Driver) driverField.get(driverInfo);
if (d == null) {
LOG.debug("Found null driver object in drivers list. Ignoring.");
continue;
}
LOG.debug("Removing non-null driver object from drivers list.");
ClassLoader registeredDriverClassLoader = d.getClass().getClassLoader();
if (registeredDriverClassLoader == null) {
LOG.debug("Found null classloader for default driver {}. Ignoring since this may be using system classloader.",
d.getClass().getName());
continue;
}
// Remove all objects in this list that were created using the classloader of the caller.
if (d.getClass().getClassLoader().equals(driverClass.getClassLoader())) {
LOG.debug("Removing default driver {} from registeredDrivers", d.getClass().getName());
list.remove(driverInfo);
}
}
}
/**
* Shuts down a cleanup thread com.mysql.jdbc.AbandonedConnectionCleanupThread that mysql driver fails to destroy
* If this is not done, the thread keeps a reference to the classloader, thereby causing OOMs or too many open files
*
* @param classLoader the unfiltered classloader of the jdbc driver class
*/
private static void shutDownMySQLAbandonedConnectionCleanupThread(ClassLoader classLoader) {
try {
Class mysqlCleanupThreadClass;
try {
mysqlCleanupThreadClass = classLoader.loadClass("com.mysql.jdbc.AbandonedConnectionCleanupThread");
} catch (ClassNotFoundException e) {
// Ok to ignore, since we may not be running mysql
LOG.trace("Failed to load MySQL abandoned connection cleanup thread class. Presuming DB App is " +
"not being run with MySQL and ignoring", e);
return;
}
Method shutdownMethod = mysqlCleanupThreadClass.getMethod("shutdown");
shutdownMethod.invoke(null);
LOG.debug("Successfully shutdown MySQL connection cleanup thread.");
} catch (Throwable e) {
// cleanup failed, ignoring silently with a log, since not much can be done.
LOG.warn("Failed to shutdown MySQL connection cleanup thread. Ignoring.", e);
}
}
private static void unregisterOracleMBean(ClassLoader classLoader) {
try {
classLoader.loadClass("oracle.jdbc.driver.OracleDriver");
} catch (ClassNotFoundException e) {
LOG.debug("Oracle JDBC Driver not found. Presuming that the DB App is not being run with an Oracle DB. " +
"Not attempting to cleanup Oracle MBean.");
return;
}
MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
Hashtable keys = new Hashtable<>();
keys.put("type", "diagnosability");
keys.put("name",
classLoader.getClass().getName() + "@" + Integer.toHexString(classLoader.hashCode()).toLowerCase());
ObjectName oracleJdbcMBeanName;
try {
oracleJdbcMBeanName = new ObjectName("com.oracle.jdbc", keys);
} catch (MalformedObjectNameException e) {
// This should never happen, since we're constructing the ObjectName correctly
LOG.debug("Exception while constructing Oracle JDBC MBean Name. Aborting cleanup.", e);
return;
}
try {
mbs.getMBeanInfo(oracleJdbcMBeanName);
} catch (InstanceNotFoundException e) {
LOG.debug("Oracle JDBC MBean not found. No cleanup necessary.");
return;
} catch (IntrospectionException | ReflectionException e) {
LOG.debug("Exception while attempting to retrieve Oracle JDBC MBean. Aborting cleanup.", e);
return;
}
try {
mbs.unregisterMBean(oracleJdbcMBeanName);
LOG.debug("Oracle MBean unregistered successfully.");
} catch (InstanceNotFoundException | MBeanRegistrationException e) {
LOG.debug("Exception while attempting to cleanup Oracle JDBCMBean. Aborting cleanup.", e);
}
}
private DBUtils() {
throw new AssertionError("Should not instantiate static utility class.");
}
}
