smiklosovic commented on code in PR #4411: URL: https://github.com/apache/cassandra/pull/4411#discussion_r2436455796
########## src/java/org/apache/cassandra/db/virtual/AbstractSchemaMetadataTable.java: ########## @@ -0,0 +1,299 @@ +/* + * 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.cassandra.db.virtual; + +import org.apache.cassandra.db.DecoratedKey; +import org.apache.cassandra.db.marshal.CompositeType; +import org.apache.cassandra.db.marshal.UTF8Type; +import org.apache.cassandra.dht.LocalPartitioner; +import org.apache.cassandra.schema.ColumnMetadata; +import org.apache.cassandra.schema.KeyspaceMetadata; +import org.apache.cassandra.schema.Schema; +import org.apache.cassandra.schema.SchemaProvider; +import org.apache.cassandra.schema.TableMetadata; +import org.apache.cassandra.db.marshal.UserType; +import org.apache.cassandra.utils.NoSpamLogger; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.nio.ByteBuffer; +import java.util.concurrent.TimeUnit; + +import com.google.common.base.Strings; + +/** + * Abstract base class for virtual tables that expose metadata on schema elements. + * <p> + * This class provides a unified implementation for tables that expose metadata across: + * <ul> + * <li>Keyspaces - metadata on keyspaces</li> + * <li>Tables - metadata on tables</li> + * <li>Columns - metadata on columns</li> + * <li>User-Defined Types (UDTs) - metadata on UDTs</li> + * </ul> + * </p> + * <p> + * Subclasses must implement methods to extract the specific metadata field + * (e.g., comment, security label) from each schema element type. + * </p> + */ +abstract class AbstractSchemaMetadataTable extends AbstractVirtualTable +{ + private static final Logger logger = LoggerFactory.getLogger(AbstractSchemaMetadataTable.class); + private static final NoSpamLogger noSpamLogger = NoSpamLogger.getLogger(logger, 1L, TimeUnit.MINUTES); + + private static final String OBJECT_TYPE = "object_type"; + private static final String KEYSPACE_NAME = "keyspace_name"; + private static final String TABLE_NAME = "table_name"; + private static final String COLUMN_NAME = "column_name"; + private static final String UDT_NAME = "udt_name"; + + private final SchemaTableType schemaTableType; + + /** + * Schema object types that can have metadata. + */ + protected enum ObjectType + { + KEYSPACE, + TABLE, + COLUMN, + UDT; + + @Override + public String toString() + { + return name(); + } + + /** + * Parse object type string to enum. + * @param objectType the string representation of the object type + * @return ObjectType enum value or null if invalid + */ + static ObjectType parse(String objectType) + { + try + { + return ObjectType.valueOf(objectType); + } + catch (IllegalArgumentException e) + { + return null; + } + } + } + + protected enum SchemaTableType + { + COMMENT("schema_comments", "comment"), + SECURITY_LABEL("schema_security_labels", "security_label"); + + private final String tableName; + private final String columnName; + + SchemaTableType(String tableName, String columnName) + { + this.tableName = tableName; + this.columnName = columnName; + } + } + + AbstractSchemaMetadataTable(String keyspace, SchemaTableType schemaTableType) + { + super(TableMetadata.builder(keyspace, schemaTableType.tableName) + .kind(TableMetadata.Kind.VIRTUAL) + .partitioner(new LocalPartitioner(CompositeType.getInstance(UTF8Type.instance, UTF8Type.instance))) + .addPartitionKeyColumn(OBJECT_TYPE, UTF8Type.instance) + .addPartitionKeyColumn(KEYSPACE_NAME, UTF8Type.instance) + .addClusteringColumn(TABLE_NAME, UTF8Type.instance) + .addClusteringColumn(COLUMN_NAME, UTF8Type.instance) + .addClusteringColumn(UDT_NAME, UTF8Type.instance) + .addRegularColumn(schemaTableType.columnName, UTF8Type.instance) + .build()); + this.schemaTableType = schemaTableType; + } + + /** + * Extract metadata from a keyspace. + * @param keyspace the keyspace metadata + * @return the metadata value, or null if not present + */ + protected abstract String extractKeyspaceMetadata(KeyspaceMetadata keyspace); + + /** + * Extract metadata from a table. + * @param table the table metadata + * @return the metadata value, or null if not present + */ + protected abstract String extractTableMetadata(TableMetadata table); + + /** + * Extract metadata from a column. + * @param column the column metadata + * @return the metadata value, or null if not present + */ + protected abstract String extractColumnMetadata(ColumnMetadata column); + + /** + * Extract metadata from a UDT. + * @param udt the user-defined type + * @return the metadata value, or null if not present + */ + protected abstract String extractUdtMetadata(UserType udt); + + @Override + public DataSet data() + { + SimpleDataSet result = new SimpleDataSet(metadata()); + SchemaProvider schemaProvider = Schema.instance; + for (String keyspaceName : schemaProvider.getKeyspaces()) + { + KeyspaceMetadata keyspace = schemaProvider.getKeyspaceMetadata(keyspaceName); + if(keyspace == null) + { + noSpamLogger.warn("Keyspace metadata not found for keyspace: {}", keyspaceName); + continue; + } + addKeyspaceRow(result, keyspace); + + for (TableMetadata table : keyspace.tables) + { + addTableRow(result, keyspace, table); + + for (ColumnMetadata column : table.columns()) + { + addColumnRow(result, keyspace, table, column); + } + } + + for (UserType udt : keyspace.types) + { + addUdtRow(result, keyspace, udt); + } + } + + return result; + } + + @Override + public DataSet data(DecoratedKey partitionKey) + { + SimpleDataSet result = new SimpleDataSet(metadata()); + + ByteBuffer key = partitionKey.getKey(); + ByteBuffer[] components = ((CompositeType) metadata().partitionKeyType).split(key); + String objectType = UTF8Type.instance.compose(components[0]); + String keyspaceName = UTF8Type.instance.compose(components[1]); + + KeyspaceMetadata keyspace = Schema.instance.getKeyspaceMetadata(keyspaceName); + if (keyspace == null) + { + logger.debug("Keyspace not found: {}", keyspaceName); + return result; + } + + ObjectType type = ObjectType.parse(objectType); + if (type == null) + { + noSpamLogger.warn("Invalid object_type in query: '{}'. Valid types are: KEYSPACE, TABLE, COLUMN, UDT", objectType); + return result; + } + + switch (type) + { + case KEYSPACE: + addKeyspaceRow(result, keyspace); + break; + Review Comment: +1 for no braces why empty lines after `break;`s? -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
