JonasJ-ap commented on code in PR #6449: URL: https://github.com/apache/iceberg/pull/6449#discussion_r1056755061
########## delta-lake/src/main/java/org/apache/iceberg/BaseMigrateDeltaLakeTableAction.java: ########## @@ -0,0 +1,322 @@ +/* + * 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.iceberg; + +import io.delta.standalone.DeltaLog; +import io.delta.standalone.VersionLog; +import io.delta.standalone.actions.Action; +import io.delta.standalone.actions.AddFile; +import io.delta.standalone.actions.RemoveFile; +import java.io.File; +import java.util.Iterator; +import java.util.List; +import java.util.Map; +import java.util.Optional; +import java.util.stream.Collectors; +import javax.annotation.Nullable; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.fs.Path; +import org.apache.iceberg.actions.BaseMigrateDeltaLakeTableActionResult; +import org.apache.iceberg.actions.MigrateDeltaLakeTable; +import org.apache.iceberg.catalog.Catalog; +import org.apache.iceberg.catalog.TableIdentifier; +import org.apache.iceberg.data.TableMigrationUtil; +import org.apache.iceberg.mapping.NameMapping; +import org.apache.iceberg.mapping.NameMappingParser; +import org.apache.iceberg.relocated.com.google.common.collect.ImmutableMap; +import org.apache.iceberg.relocated.com.google.common.collect.Iterables; +import org.apache.iceberg.relocated.com.google.common.collect.Lists; +import org.apache.iceberg.relocated.com.google.common.collect.Maps; +import org.apache.iceberg.types.Type; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +public class BaseMigrateDeltaLakeTableAction implements MigrateDeltaLakeTable { + + private static final Logger LOG = LoggerFactory.getLogger(BaseMigrateDeltaLakeTableAction.class); + private final String parquetSuffix = ".parquet"; + private final String avroSuffix = ".avro"; + private final String orcSuffix = ".orc"; + private final Map<String, String> additionalProperties = Maps.newHashMap(); + private final DeltaLog deltaLog; + private final Catalog icebergCatalog; + private final String deltaTableLocation; + private final TableIdentifier newTableIdentifier; + private final Configuration hadoopConfiguration; + + public BaseMigrateDeltaLakeTableAction( + Catalog icebergCatalog, + String deltaTableLocation, + TableIdentifier newTableIdentifier, + Configuration hadoopConfiguration) { + this.icebergCatalog = icebergCatalog; + this.deltaTableLocation = deltaTableLocation; + this.newTableIdentifier = newTableIdentifier; + this.hadoopConfiguration = hadoopConfiguration; + // TODO: check whether we can retrieve hadoopConfiguration directly + this.deltaLog = DeltaLog.forTable(this.hadoopConfiguration, this.deltaTableLocation); + } + + @Override + public MigrateDeltaLakeTable tableProperties(Map<String, String> properties) { + additionalProperties.putAll(properties); + return this; + } + + @Override + public Result execute() { + io.delta.standalone.Snapshot updatedSnapshot = deltaLog.update(); + Schema schema = convertDeltaLakeSchema(updatedSnapshot.getMetadata().getSchema()); + PartitionSpec partitionSpec = getPartitionSpecFromDeltaSnapshot(schema); + // TODO: check whether we need more info when initializing the table + Table icebergTable = + this.icebergCatalog.createTable( + newTableIdentifier, + schema, + partitionSpec, + destTableProperties( + updatedSnapshot, this.deltaTableLocation, this.additionalProperties)); + + copyFromDeltaLakeToIceberg(icebergTable, partitionSpec); + + Snapshot snapshot = icebergTable.currentSnapshot(); + long totalDataFiles = + Long.parseLong(snapshot.summary().get(SnapshotSummary.TOTAL_DATA_FILES_PROP)); + LOG.info( + "Successfully loaded Iceberg metadata for {} files to {}", + totalDataFiles, + deltaTableLocation); + return new BaseMigrateDeltaLakeTableActionResult(totalDataFiles); + } + + /** TODO: check the correctness for nested schema */ + private Schema convertDeltaLakeSchema(io.delta.standalone.types.StructType deltaSchema) { + Type converted = + DeltaLakeDataTypeVisitor.visit(deltaSchema, new DeltaLakeTypeToType(deltaSchema)); + return new Schema(converted.asNestedType().asStructType().fields()); + } + + private PartitionSpec getPartitionSpecFromDeltaSnapshot(Schema schema) { + List<String> partitionNames = deltaLog.snapshot().getMetadata().getPartitionColumns(); + if (partitionNames.isEmpty()) { + return PartitionSpec.unpartitioned(); + } + + PartitionSpec.Builder builder = PartitionSpec.builderFor(schema); + for (String partitionName : partitionNames) { + builder.identity(partitionName); + } + return builder.build(); + } + + private void copyFromDeltaLakeToIceberg(Table table, PartitionSpec spec) { + // TODO: double check the arguments' meaning here + Iterator<VersionLog> it = + deltaLog.getChanges( + 0, // retrieve actions starting from the initial version + false); // not throw exception when data loss detected + + while (it.hasNext()) { + VersionLog versionLog = it.next(); + List<Action> actions = versionLog.getActions(); + + // We first need to iterate through to see what kind of transaction this was. There are 3 + // cases: + // 1. AppendFile - when there are only AddFile instances (an INSERT on the table) + // 2. DeleteFiles - when there are only RemoveFile instances (a DELETE where all the records + // of file(s) were removed + // 3. OverwriteFiles - when there are a mix of AddFile and RemoveFile (a DELETE/UPDATE) + + // Create a map of Delta Lake Action (AddFile, RemoveFile, etc.) --> List<Action> + Map<String, List<Action>> deltaLakeActionMap = + actions.stream() + .filter(action -> action instanceof AddFile || action instanceof RemoveFile) + .collect(Collectors.groupingBy(a -> a.getClass().getSimpleName())); + + // Scan the map so that we know what type of transaction this will be in Iceberg + IcebergTransactionType icebergTransactionType = + getIcebergTransactionTypeFromDeltaActions(deltaLakeActionMap); + if (icebergTransactionType == null) { + // TODO: my understanding here is that if the transaction type is undefined, + // we can no longer continue even the next versionLog contains valid transaction type + // may need further check + return; + } + + List<DataFile> filesToAdd = Lists.newArrayList(); Review Comment: Thank you for your suggestion. I refactored the logic to rely on the size of `filesToAdd` and `filesToRemove` to directly determine what transaction to use. -- 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: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
