ctubbsii commented on code in PR #5451: URL: https://github.com/apache/accumulo/pull/5451#discussion_r2054688720
########## core/src/main/java/org/apache/accumulo/core/util/tables/TableMapping.java: ########## @@ -0,0 +1,190 @@ +/* + * 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 + * + * https://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.accumulo.core.util.tables; + +import static java.util.Collections.emptySortedMap; +import static java.util.Objects.requireNonNull; +import static org.apache.accumulo.core.clientImpl.NamespaceMapping.deserializeMap; +import static org.apache.accumulo.core.clientImpl.NamespaceMapping.serializeMap; + +import java.util.Map; +import java.util.SortedMap; + +import org.apache.accumulo.core.Constants; +import org.apache.accumulo.core.clientImpl.AcceptableThriftTableOperationException; +import org.apache.accumulo.core.clientImpl.ClientContext; +import org.apache.accumulo.core.clientImpl.Namespace; +import org.apache.accumulo.core.clientImpl.thrift.TableOperation; +import org.apache.accumulo.core.clientImpl.thrift.TableOperationExceptionType; +import org.apache.accumulo.core.data.NamespaceId; +import org.apache.accumulo.core.data.TableId; +import org.apache.accumulo.core.metadata.AccumuloTable; +import org.apache.accumulo.core.zookeeper.ZcStat; +import org.apache.accumulo.core.zookeeper.ZooCache; +import org.apache.zookeeper.KeeperException; + +import com.google.common.base.MoreObjects; +import com.google.common.collect.ImmutableSortedMap; + +public class TableMapping { + + private final ClientContext context; + private final NamespaceId namespaceId; + private final String mappingPath; + private volatile SortedMap<TableId,String> currentTableMap = emptySortedMap(); + private volatile SortedMap<String,TableId> currentTableReverseMap = emptySortedMap(); + private volatile long lastMzxid; + + public TableMapping(ClientContext context, NamespaceId namespaceId) { + this.context = requireNonNull(context); + this.namespaceId = requireNonNull(namespaceId); + this.mappingPath = getZTableMapPath(namespaceId); + } + + public void put(TableId tableId, String tableName, TableOperation operation) + throws InterruptedException, KeeperException, AcceptableThriftTableOperationException { + requireNonNull(tableId); + var rawTableName = TableNameUtil.qualify(requireNonNull(tableName)).getSecond(); + requireNonNull(operation); + if (isBuiltInZKTable(tableId)) { + throw new AssertionError("Putting built-in tables in map should not be possible after init"); + } + context.getZooSession().asReaderWriter().mutateExisting(mappingPath, data -> { + var tables = deserializeMap(data); + final String currentName = tables.get(tableId.canonical()); + if (rawTableName.equals(currentName)) { + return null; // mapping already exists; operation is idempotent, so no change needed + } + if (currentName != null) { + throw new AcceptableThriftTableOperationException(tableId.canonical(), null, operation, + TableOperationExceptionType.EXISTS, "Table Id already exists"); + } + if (tables.containsValue(rawTableName)) { + throw new AcceptableThriftTableOperationException(tableId.canonical(), tableName, operation, + TableOperationExceptionType.EXISTS, "Table name already exists"); + } + tables.put(tableId.canonical(), rawTableName); + return serializeMap(tables); + }); + } + + public void remove(final TableId tableId) + throws InterruptedException, KeeperException, AcceptableThriftTableOperationException { + requireNonNull(tableId); + if (isBuiltInZKTable(tableId)) { + throw new AssertionError("Removing built-in tables in map should not be possible"); + } + context.getZooSession().asReaderWriter().mutateExisting(mappingPath, data -> { + var tables = deserializeMap(data); + if (!tables.containsKey(tableId.canonical())) { + throw new AcceptableThriftTableOperationException(null, tableId.canonical(), + TableOperation.DELETE, TableOperationExceptionType.NOTFOUND, + "Table already removed while processing"); + } + tables.remove(tableId.canonical()); + return serializeMap(tables); + }); + } + + public void rename(final TableId tableId, final String oldName, final String newName) + throws InterruptedException, KeeperException, AcceptableThriftTableOperationException { + requireNonNull(tableId); + var rawOldName = TableNameUtil.qualify(requireNonNull(oldName)).getSecond(); + var rawNewName = TableNameUtil.qualify(requireNonNull(newName)).getSecond(); + if (isBuiltInZKTable(tableId)) { + throw new AssertionError("Renaming built-in tables in map should not be possible"); + } + context.getZooSession().asReaderWriter().mutateExisting(mappingPath, data -> { + var tables = deserializeMap(data); + final String currentName = tables.get(tableId.canonical()); + if (rawNewName.equals(currentName)) { + return null; // assume in this case the operation is running again, so we are done + } + if (!rawOldName.equals(currentName)) { + throw new AcceptableThriftTableOperationException(null, oldName, TableOperation.RENAME, + TableOperationExceptionType.NOTFOUND, "Name changed while processing"); + } + if (tables.containsValue(rawNewName)) { + throw new AcceptableThriftTableOperationException(null, newName, TableOperation.RENAME, + TableOperationExceptionType.EXISTS, "Table name already exists"); + } + tables.put(tableId.canonical(), rawNewName); + return serializeMap(tables); + }); + } + + private synchronized void update() { + final ZooCache zc = context.getZooCache(); + final ZcStat stat = new ZcStat(); + + byte[] data = zc.get(mappingPath, stat); + if (stat.getMzxid() > lastMzxid) { + if (data == null) { + throw new IllegalStateException(mappingPath + " node should not be null"); + } + Map<String,String> idToName = deserializeMap(data); + if (namespaceId.equals(Namespace.ACCUMULO.id())) { + for (TableId tid : AccumuloTable.allTableIds()) { + if (!idToName.containsKey(tid.canonical())) { + throw new IllegalStateException("Built-in tables are not present in map"); + } + } Review Comment: Instead of the loop to check that everything is contained as a subset of the keys, you could so something like the following to check the whole mapping and print the expected and actual mapping contents in the error message ```java if (!idToName.equals(AccumuloTable.tableMapping()) { throw new IllegalStateException ("Accumulo namespace expected to contain tables " + AccumuloTable.tableMapping() + ", but saw " + idToName); } ``` This new mapping method on the AccumuloTable class that I'm suggesting here could also be used by the initialize code for creating the initial mapping. It's also possible that the mapping for the Accumulo namespace doesn't need to be stored in ZooKeeper at all, and we could just use the in-code mapping and return that when the mapping is looked up for the namespace, rather than read from ZooKeeper. However, I'd be concerned about having too many "special" code paths for these special cases, as that's harder to maintain later. It might be better to use the same code path for all namespaces, and just have these kinds of built-in checks for detectable corruption. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: notifications-unsubscr...@accumulo.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
