rdblue commented on a change in pull request #695: [WIP] Cherrypick snapshot feature URL: https://github.com/apache/incubator-iceberg/pull/695#discussion_r358522255
########## File path: core/src/main/java/org/apache/iceberg/CherryPickFromSnapshot.java ########## @@ -0,0 +1,225 @@ +/* + * 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 com.google.common.base.Preconditions; +import com.google.common.collect.Iterables; +import com.google.common.collect.Lists; +import java.io.IOException; +import java.util.Arrays; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.concurrent.atomic.AtomicInteger; +import org.apache.iceberg.exceptions.CommitFailedException; +import org.apache.iceberg.exceptions.RuntimeIOException; +import org.apache.iceberg.exceptions.ValidationException; +import org.apache.iceberg.io.OutputFile; +import org.apache.iceberg.util.Tasks; +import org.apache.iceberg.util.ThreadPools; + +/** + * In an audit workflow, new data is written to an orphan snapshot that is not committed as the table's + * current state until it is audited. After auditing a change, it may need to be applied or cherry-picked + * on top of the latest snapshot instead of the one that was current when the audited changes were created. + * + * This class adds support for cherry-picking the changes from an orphan snapshot by applying them to + * the current snapshot. The output of the operation is a new snapshot with the changes from cherry-picked + * snapshot. + * + * Cherry-picking should apply the exact set of changes that were done in the original commit. + * - All added files should be added to the new version. + * - Todo: If files were deleted, then those files must still exist in the data set. + * - Does not support Overwrite operations currently. Overwrites are considered as conflicts. + * + */ +class CherryPickFromSnapshot extends MergingSnapshotProducer<AppendFiles> implements CherryPick { + private final TableOperations ops; + private TableMetadata base = null; + private Long cherryPickSnapshotId = null; + private final AtomicInteger manifestCount = new AtomicInteger(0); + + CherryPickFromSnapshot(TableOperations ops) { + super(ops); + this.ops = ops; + this.base = ops.refresh(); + } + + @Override + protected AppendFiles self() { + throw new UnsupportedOperationException("Not supported"); + } + + /** + * We only cherry pick for appends right now + * @return + */ + @Override + protected String operation() { + return DataOperations.APPEND; + } + + @Override + public CherryPickFromSnapshot fromSnapshotId(long snapshotId) { + Preconditions.checkArgument(base.snapshot(snapshotId) != null, + "Cannot cherry pick unknown snapshot id: %s", snapshotId); + + this.cherryPickSnapshotId = snapshotId; + return this; + } + + /** + * Apply the pending changes and return the uncommitted changes for validation. + * <p> + * This does not result in a permanent update. + * + * @return the uncommitted changes that would be committed by calling {@link #commit()} + * @throws ValidationException If the pending changes cannot be applied to the current metadata + * @throws IllegalArgumentException If the pending changes are conflicting or invalid + */ + @Override + public Snapshot apply() { + ValidationException.check(cherryPickSnapshotId != null, + "Cannot cherry pick unknown version: call fromSnapshotId"); + + Snapshot cherryPickSnapshot = base.snapshot(cherryPickSnapshotId); + String wapId = stagedWapId(cherryPickSnapshot); + ValidationException.check(wapId != null, + "Snapshot provided for cherrypick didn't have wap.id set on it. " + + "Only snapshots that were staged can be cherrypicked from."); + ValidationException.check(!base.isWapIdPublished(Long.parseLong(wapId)), + "Duplicate request to cherry pick wap id that was published already: %s", wapId); + + // only append operations are currently supported + if (!cherryPickSnapshot.operation().equals(DataOperations.APPEND)) { + throw new UnsupportedOperationException("Can cherry pick only append operations"); + } + + Snapshot currentSnapshot = base.currentSnapshot(); + Long parentSnapshotId = base.currentSnapshot() != null ? + base.currentSnapshot().snapshotId() : null; + + // Todo: + // - Check if files to be deleted exist in current snapshot, + // ignore those files or reject incoming snapshot entirely? + // - Check if there are overwrites, ignore those files or reject incoming snapshot entirely? + + // create manifest file by picking Appends from cherry-pick snapshot + List<ManifestFile> newManifestFiles = Lists.newArrayList(); + long outputSnapshotId = snapshotId(); + try { + ManifestFile newManifestFile = createManifestFromAppends(cherryPickSnapshot.manifests(), outputSnapshotId); + newManifestFiles.add(newManifestFile); + } catch (IOException ioe) { + throw new RuntimeIOException(ioe, "Failed to create new manifest from cherry pick snapshot"); + } + List<ManifestFile> manifestsForNewSnapshot = Lists.newArrayList(Iterables.concat( + newManifestFiles, currentSnapshot.manifests())); + + // write out the manifest list + OutputFile manifestList = createManifestList(parentSnapshotId, outputSnapshotId, manifestsForNewSnapshot); + + // create a fresh snapshot with changes from cherry pick snapshot and previous Table metadata + Map<String, String> summaryForNewSnapshot = new HashMap<>(summary(base)); + // register this wap id as che + summaryForNewSnapshot.put(SnapshotSummary.PUBLISHED_WAP_ID_PROP, wapId); + Snapshot outputSnapshot = new BaseSnapshot(ops.io(), + outputSnapshotId, parentSnapshotId, System.currentTimeMillis(), cherryPickSnapshot.operation(), + summaryForNewSnapshot, ops.io().newInputFile(manifestList.location())); + TableMetadata updated = base.addStagedSnapshot(outputSnapshot); + ops.commit(base, updated); + + return outputSnapshot; + } + + private static String stagedWapId(Snapshot snapshot) { + return snapshot.summary() != null ? snapshot.summary().getOrDefault("wap.id", null) : null; + } + + private OutputFile createManifestList( + Long parentSnapshotId, + long outputSnapshotId, + List<ManifestFile> manifestsForNewSnapshot) { + OutputFile manifestList = manifestListPath(); + try (ManifestListWriter listWriter = new ManifestListWriter( + manifestList, outputSnapshotId, parentSnapshotId)) { + + ManifestFile[] manifestFiles = new ManifestFile[manifestsForNewSnapshot.size()]; + Tasks.range(manifestFiles.length) + .stopOnFailure().throwFailureWhenFinished() + .executeWith(ThreadPools.getWorkerPool()) + .run(index -> + manifestFiles[index] = manifestsForNewSnapshot.get(index)); + + listWriter.addAll(Arrays.asList(manifestFiles)); + + } catch (IOException e) { + throw new RuntimeIOException(e, "Failed to write manifest list file"); + } + return manifestList; + } + + /** + * Apply the pending changes and commit. + * <p> + * Changes are committed by calling the underlying table's commit method. + * <p> + * Once the commit is successful, the updated table will be refreshed. + * + * @throws ValidationException If the update cannot be applied to the current table metadata. + * @throws CommitFailedException If the update cannot be committed due to conflicts. + */ + @Override + public void commit() { + // Todo: Need to add retry + Snapshot outputSnapshot = apply(); + base = ops.refresh(); + ops.commit(base, base.cherrypickFrom(outputSnapshot)); + } + + /** + * Looks for manifest entries that have append files from cherry-pick snapshot + * and creates a new ManifestFile with a new snapshot + */ + private ManifestFile createManifestFromAppends(List<ManifestFile> inputManifests, long outputSnapshotId) + throws IOException { + + OutputFile out = manifestPath(manifestCount.getAndIncrement()); + // create a manifest writer with new snapshot id + ManifestWriter writer = new ManifestWriter(ops.current().spec(), out, outputSnapshotId); + try { + for (ManifestFile manifest : inputManifests) { Review comment: This should filter the manifests that are scanned using metadata, like [`Snapshot.addedFiles`](https://github.com/apache/incubator-iceberg/blob/master/core/src/main/java/org/apache/iceberg/BaseSnapshot.java#L162-L167) does. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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