ndimiduk commented on a change in pull request #1020: HBASE-23653 Expose content of meta table in web ui URL: https://github.com/apache/hbase/pull/1020#discussion_r366467988
########## File path: hbase-server/src/main/java/org/apache/hadoop/hbase/master/webapp/MetaBrowser.java ########## @@ -0,0 +1,378 @@ +/* + * 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.master.webapp; + +import java.io.UnsupportedEncodingException; +import java.net.URLDecoder; +import java.net.URLEncoder; +import java.nio.charset.StandardCharsets; +import java.util.ArrayList; +import java.util.Collection; +import java.util.Iterator; +import java.util.LinkedList; +import java.util.List; +import java.util.stream.StreamSupport; +import javax.servlet.http.HttpServletRequest; +import org.apache.commons.lang3.StringUtils; +import org.apache.commons.lang3.builder.ToStringBuilder; +import org.apache.commons.lang3.builder.ToStringStyle; +import org.apache.hadoop.hbase.CompareOperator; +import org.apache.hadoop.hbase.HConstants; +import org.apache.hadoop.hbase.TableName; +import org.apache.hadoop.hbase.client.AdvancedScanResultConsumer; +import org.apache.hadoop.hbase.client.AsyncConnection; +import org.apache.hadoop.hbase.client.AsyncTable; +import org.apache.hadoop.hbase.client.ResultScanner; +import org.apache.hadoop.hbase.client.Scan; +import org.apache.hadoop.hbase.filter.Filter; +import org.apache.hadoop.hbase.filter.FilterList; +import org.apache.hadoop.hbase.filter.PrefixFilter; +import org.apache.hadoop.hbase.filter.SingleColumnValueFilter; +import org.apache.hadoop.hbase.master.RegionState; +import org.apache.hadoop.hbase.util.Bytes; +import org.apache.yetus.audience.InterfaceAudience; +import org.apache.hbase.thirdparty.com.google.common.collect.Iterators; +import org.apache.hbase.thirdparty.io.netty.handler.codec.http.QueryStringEncoder; + +/** + * A support class for the "Meta Entries" section in + * {@code resources/hbase-webapps/master/table.jsp}. + */ +@InterfaceAudience.Private +public class MetaBrowser { + public static final String NAME_PARAM = "name"; + public static final String SCAN_LIMIT_PARAM = "scan_limit"; + public static final String SCAN_REGION_STATE_PARAM = "scan_region_state"; + public static final String SCAN_START_PARAM = "scan_start"; + public static final String SCAN_TABLE_PARAM = "scan_table"; + + public static final int SCAN_LIMIT_DEFAULT = 10; + public static final int SCAN_LIMIT_MAX = 10_000; + + private final AsyncConnection connection; + private final HttpServletRequest request; + private final List<String> errorMessages; + private final String name; + private final Integer scanLimit; + private final RegionState.State scanRegionState; + private final byte[] scanStart; + private final TableName scanTable; + + public MetaBrowser(final AsyncConnection connection, final HttpServletRequest request) { + this.connection = connection; + this.request = request; + this.errorMessages = new LinkedList<>(); + this.name = resolveName(request); + this.scanLimit = resolveScanLimit(request); + this.scanRegionState = resolveScanRegionState(request); + this.scanStart = resolveScanStart(request); + this.scanTable = resolveScanTable(request); + } + + public List<String> getErrorMessages() { + return errorMessages; + } + + public String getName() { + return name; + } + + public Integer getScanLimit() { + return scanLimit; + } + + public byte[] getScanStart() { + return scanStart; + } + + public RegionState.State getScanRegionState() { + return scanRegionState; + } + + public TableName getScanTable() { + return scanTable; + } + + public Results getResults() { + final AsyncTable<AdvancedScanResultConsumer> asyncTable = + connection.getTable(TableName.META_TABLE_NAME); + return new Results(asyncTable.getScanner(buildScan())); + } + + @Override + public String toString() { + return new ToStringBuilder(this, ToStringStyle.SHORT_PREFIX_STYLE) + .append("scanStart", scanStart) + .append("scanLimit", scanLimit) + .append("scanTable", scanTable) + .append("scanRegionState", scanRegionState) + .toString(); + } + + private static String resolveName(final HttpServletRequest request) { + return resolveRequestParameter(request, NAME_PARAM); + } + + private Integer resolveScanLimit(final HttpServletRequest request) { + final String requestValueStr = resolveRequestParameter(request, SCAN_LIMIT_PARAM); + if (StringUtils.isBlank(requestValueStr)) { + return null; + } + + final Integer requestValue = tryParseInt(requestValueStr); + if (requestValue == null) { + errorMessages.add(buildScanLimitMalformedErrorMessage(requestValueStr)); + return null; + } + if (requestValue <= 0) { + errorMessages.add(buildScanLimitLTEZero(requestValue)); + return SCAN_LIMIT_DEFAULT; + } + + final int truncatedValue = Math.min(requestValue, SCAN_LIMIT_MAX); + if (requestValue != truncatedValue) { + errorMessages.add(buildScanLimitExceededErrorMessage(requestValue)); + } + return truncatedValue; + } + + private RegionState.State resolveScanRegionState(final HttpServletRequest request) { + final String requestValueStr = resolveRequestParameter(request, SCAN_REGION_STATE_PARAM); + if (requestValueStr == null) { + return null; + } + final RegionState.State requestValue = tryValueOf(RegionState.State.class, requestValueStr); + if (requestValue == null) { + errorMessages.add(buildScanRegionStateMalformedErrorMessage(requestValueStr)); + return null; + } + return requestValue; + } + + private static byte[] resolveScanStart(final HttpServletRequest request) { + final String requestValue = resolveRequestParameter(request, SCAN_START_PARAM); + if (requestValue == null) { + return null; + } + return Bytes.toBytesBinary(requestValue); + } + + private static TableName resolveScanTable(final HttpServletRequest request) { + final String requestValue = resolveRequestParameter(request, SCAN_TABLE_PARAM); + if (requestValue == null) { + return null; + } + return TableName.valueOf(requestValue); + } + + private static String resolveRequestParameter(final HttpServletRequest request, + final String param) { + if (request == null) { + return null; + } + final String requestValueStrEnc = request.getParameter(param); + if (StringUtils.isBlank(requestValueStrEnc)) { + return null; + } + return urlDecode(requestValueStrEnc); + } + + private static Filter buildTableFilter(final TableName tableName) { + return new PrefixFilter(tableName.toBytes()); + } + + private static Filter buildScanRegionStateFilter(final RegionState.State state) { + return new SingleColumnValueFilter( + HConstants.CATALOG_FAMILY, + HConstants.STATE_QUALIFIER, + CompareOperator.EQUAL, + // use the same serialization strategy as found in MetaTableAccessor#addRegionStateToPut + Bytes.toBytes(state.name())); + } + + private Filter buildScanFilter() { + if (scanTable == null && scanRegionState == null) { + return null; + } + + final List<Filter> filters = new ArrayList<>(2); + if (scanTable != null) { + filters.add(buildTableFilter(scanTable)); + } + if (scanRegionState != null) { + filters.add(buildScanRegionStateFilter(scanRegionState)); + } + if (filters.size() == 1) { + return filters.get(0); + } + return new FilterList(FilterList.Operator.MUST_PASS_ALL, filters); + } + + private Scan buildScan() { + final Scan metaScan = new Scan() + .addFamily(HConstants.CATALOG_FAMILY) + .readVersions(1) + .setLimit((scanLimit != null ? scanLimit : SCAN_LIMIT_DEFAULT) + 1); 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