/*
* Copyright 2010 The Apache Software Foundation
*
* 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.hadoop.hbase.rest;
import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.ws.rs.Encoded;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.QueryParam;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.TableNotFoundException;
import org.apache.hadoop.hbase.client.HBaseAdmin;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.rest.transform.NullTransform;
import org.apache.hadoop.hbase.rest.transform.Transform;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.util.StringUtils;
public class TableResource extends ResourceBase {
private static final Log LOG = LogFactory.getLog(TableResource.class);
/**
* HCD attributes starting with this string are considered transform
* directives
*/
private static final String DIRECTIVE_KEY = "Transform$";
/**
* Transform directives are of the form <tt><qualifier>:<class></tt>
* where <tt>qualifier</tt> is a string for exact matching or '*' as a wildcard
* that will match anything; and <tt>class</tt> is either the fully qualified
* class name of a transform implementation or can be the short name of a
* transform in the <tt>org.apache.hadoop.hbase.rest.transform package</tt>.
*/
private static final Pattern DIRECTIVE_PATTERN =
Pattern.compile("([^\\:]+)\\:([^\\,]+)\\,?");
private static final Transform defaultTransform = new NullTransform();
private static final
Map<String,Map<byte[],Map<byte[],Transform>>> transformMap =
new ConcurrentHashMap<String,Map<byte[],Map<byte[],Transform>>>();
private static final Map<String,Long> lastCheckedMap =
new ConcurrentHashMap<String,Long>();
/**
* @param table the table
* @param family the column family
* @param qualifier the column qualifier, or null
* @return the transformation specified for the given family or qualifier, if
* any, otherwise the default
*/
static Transform getTransform(String table, byte[] family, byte[] qualifier) {
if (qualifier == null) {
qualifier = HConstants.EMPTY_BYTE_ARRAY;
}
Map<byte[],Map<byte[],Transform>> familyMap = transformMap.get(table);
if (familyMap != null) {
Map<byte[],Transform> columnMap = familyMap.get(family);
if (columnMap != null) {
Transform t = columnMap.get(qualifier);
// check as necessary if there is a wildcard entry
if (t == null) {
t = columnMap.get(HConstants.EMPTY_BYTE_ARRAY);
}
// if we found something, return it, otherwise we will return the
// default by falling through
if (t != null) {
return t;
}
}
}
return defaultTransform;
}
synchronized static void setTransform(String table, byte[] family,
byte[] qualifier, Transform transform) {
Map<byte[],Map<byte[],Transform>> familyMap = transformMap.get(table);
if (familyMap == null) {
familyMap = new ConcurrentSkipListMap<byte[],Map<byte[],Transform>>(
Bytes.BYTES_COMPARATOR);
transformMap.put(table, familyMap);
}
Map<byte[],Transform> columnMap = familyMap.get(family);
if (columnMap == null) {
columnMap = new ConcurrentSkipListMap<byte[],Transform>(
Bytes.BYTES_COMPARATOR);
familyMap.put(family, columnMap);
}
// if transform is null, remove any existing entry
if (transform != null) {
columnMap.put(qualifier, transform);
} else {
columnMap.remove(qualifier);
}
}
String table;
/**
* Scan the table schema for transform directives. These are column family
* attributes containing a comma-separated list of elements of the form
* <tt><qualifier>:<transform-class></tt>, where qualifier
* can be a string for exact matching or '*' as a wildcard to match anything.
* The attribute key must begin with the string "Transform$".
*/
void scanTransformAttrs() throws IOException {
try {
HBaseAdmin admin = new HBaseAdmin(servlet.getConfiguration());
HTableDescriptor htd = admin.getTableDescriptor(Bytes.toBytes(table));
for (HColumnDescriptor hcd: htd.getFamilies()) {
for (Map.Entry<ImmutableBytesWritable, ImmutableBytesWritable> e:
hcd.getValues().entrySet()) {
// does the key start with the transform directive tag?
String key = Bytes.toString(e.getKey().get());
if (!key.startsWith(DIRECTIVE_KEY)) {
// no, skip
continue;
}
// match a comma separated list of one or more directives
byte[] value = e.getValue().get();
Matcher m = DIRECTIVE_PATTERN.matcher(Bytes.toString(value));
while (m.find()) {
byte[] qualifier = HConstants.EMPTY_BYTE_ARRAY;
String s = m.group(1);
if (s.length() > 0 && !s.equals("*")) {
qualifier = Bytes.toBytes(s);
}
boolean retry = false;
String className = m.group(2);
while (true) {
try {
// if a transform was previously configured for the qualifier,
// this will simply replace it
setTransform(table, hcd.getName(), qualifier,
(Transform)Class.forName(className).newInstance());
break;
} catch (InstantiationException ex) {
LOG.error(StringUtils.stringifyException(ex));
if (retry) {
break;
}
retry = true;
} catch (IllegalAccessException ex) {
LOG.error(StringUtils.stringifyException(ex));
if (retry) {
break;
}
retry = true;
} catch (ClassNotFoundException ex) {
if (retry) {
LOG.error(StringUtils.stringifyException(ex));
break;
}
className = "org.apache.hadoop.hbase.rest.transform." + className;
retry = true;
}
}
}
}
}
} catch (TableNotFoundException e) {
// ignore
}
}
/**
* Constructor
* @param table
* @throws IOException
*/
public TableResource(String table) throws IOException {
super();
this.table = table;
// Scanning the table schema is too expensive to do for every operation.
// Do it once per minute by default.
// Setting hbase.rest.transform.check.interval to <= 0 disables rescanning.
long now = System.currentTimeMillis();
Long lastChecked = lastCheckedMap.get(table);
if (lastChecked != null) {
long interval = servlet.getConfiguration()
.getLong("hbase.rest.transform.check.interval", 60000);
if (interval > 0 && (now - lastChecked.longValue()) > interval) {
scanTransformAttrs();
lastCheckedMap.put(table, now);
}
} else {
scanTransformAttrs();
lastCheckedMap.put(table, now);
}
}
/** @return the table name */
String getName() {
return table;
}
/**
* @return true if the table exists
* @throws IOException
*/
boolean exists() throws IOException {
HBaseAdmin admin = new HBaseAdmin(servlet.getConfiguration());
return admin.tableExists(table);
}
/**
* Apply any configured transformations to the value
* @param family
* @param qualifier
* @param value
* @param direction
* @return
* @throws IOException
*/
byte[] transform(byte[] family, byte[] qualifier, byte[] value,
Transform.Direction direction) throws IOException {
Transform t = getTransform(table, family, qualifier);
if (t != null) {
return t.transform(value, direction);
}
return value;
}
@Path("exists")
public ExistsResource getExistsResource() throws IOException {
return new ExistsResource(this);
}
@Path("regions")
public RegionsResource getRegionsResource() throws IOException {
return new RegionsResource(this);
}
@Path("scanner")
public ScannerResource getScannerResource() throws IOException {
return new ScannerResource(this);
}
@Path("schema")
public SchemaResource getSchemaResource() throws IOException {
return new SchemaResource(this);
}
@Path("multiget")
public MultiRowResource getMultipleRowResource(
final @QueryParam("v") String versions) throws IOException {
return new MultiRowResource(this, versions);
}
@Path("{rowspec: .+}")
public RowResource getRowResource(
// We need the @Encoded decorator so Jersey won't urldecode before
// the RowSpec constructor has a chance to parse
final @PathParam("rowspec") @Encoded String rowspec,
final @QueryParam("v") String versions) throws IOException {
return new RowResource(this, rowspec, versions);
}
}