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hudi/hoodie-client/src/main/java/com/uber/hoodie/HoodieReadClient.java
2017-02-27 15:52:13 -08:00

296 lines
12 KiB
Java

/*
* Copyright (c) 2016 Uber Technologies, Inc. (hoodie-dev-group@uber.com)
*
* Licensed 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 com.uber.hoodie;
import com.google.common.base.Optional;
import com.uber.hoodie.common.model.HoodieCommitMetadata;
import com.uber.hoodie.common.model.HoodieDataFile;
import com.uber.hoodie.common.model.HoodieKey;
import com.uber.hoodie.common.model.HoodieRecord;
import com.uber.hoodie.common.table.HoodieTableMetaClient;
import com.uber.hoodie.common.table.HoodieTimeline;
import com.uber.hoodie.common.table.TableFileSystemView;
import com.uber.hoodie.common.table.timeline.HoodieInstant;
import com.uber.hoodie.common.util.FSUtils;
import com.uber.hoodie.config.HoodieWriteConfig;
import com.uber.hoodie.exception.HoodieException;
import com.uber.hoodie.index.HoodieBloomIndex;
import com.uber.hoodie.table.HoodieTable;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaPairRDD;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.sql.Dataset;
import org.apache.spark.sql.Row;
import org.apache.spark.sql.SQLContext;
import org.apache.spark.sql.types.StructType;
import java.io.IOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;
import scala.Tuple2;
/**
* Provides first class support for accessing Hoodie tables for data processing via Apache Spark.
*
*
* TODO: Need to move all read operations here, since Hoodie is a single writer and multiple reader
*/
public class HoodieReadClient implements Serializable {
private static Logger logger = LogManager.getLogger(HoodieReadClient.class);
private transient final JavaSparkContext jsc;
private transient final FileSystem fs;
/**
* TODO: We need to persist the index type into hoodie.properties and be able to access the
* index just with a simple basepath pointing to the dataset. Until, then just always assume a
* BloomIndex
*/
private transient final HoodieBloomIndex index;
private final HoodieTimeline commitTimeline;
private HoodieTable hoodieTable;
private transient Optional<SQLContext> sqlContextOpt;
/**
* @param basePath path to Hoodie dataset
*/
public HoodieReadClient(JavaSparkContext jsc, String basePath) {
this.jsc = jsc;
this.fs = FSUtils.getFs();
// Create a Hoodie table which encapsulated the commits and files visible
this.hoodieTable = HoodieTable
.getHoodieTable(new HoodieTableMetaClient(fs, basePath, true), null);
this.commitTimeline = hoodieTable.getCompletedCompactionCommitTimeline();
this.index =
new HoodieBloomIndex(HoodieWriteConfig.newBuilder().withPath(basePath).build(), jsc);
this.sqlContextOpt = Optional.absent();
}
/**
*
* @param jsc
* @param basePath
* @param sqlContext
*/
public HoodieReadClient(JavaSparkContext jsc, String basePath, SQLContext sqlContext) {
this(jsc, basePath);
this.sqlContextOpt = Optional.of(sqlContext);
}
/**
* Adds support for accessing Hoodie built tables from SparkSQL, as you normally would.
*
* @return SparkConf object to be used to construct the SparkContext by caller
*/
public static SparkConf addHoodieSupport(SparkConf conf) {
conf.set("spark.sql.hive.convertMetastoreParquet", "false");
return conf;
}
private void assertSqlContext() {
if (!sqlContextOpt.isPresent()) {
throw new IllegalStateException("SQLContext must be set, when performing dataframe operations");
}
}
/**
* Given a bunch of hoodie keys, fetches all the individual records out as a data frame
*
* @return a dataframe
*/
public Dataset<Row> read(JavaRDD<HoodieKey> hoodieKeys, int parallelism)
throws Exception {
assertSqlContext();
JavaPairRDD<HoodieKey, Optional<String>> keyToFileRDD =
index.fetchRecordLocation(hoodieKeys, hoodieTable);
List<String> paths = keyToFileRDD
.filter(keyFileTuple -> keyFileTuple._2().isPresent())
.map(keyFileTuple -> keyFileTuple._2().get())
.collect();
// record locations might be same for multiple keys, so need a unique list
Set<String> uniquePaths = new HashSet<>(paths);
Dataset<Row> originalDF = sqlContextOpt.get().read()
.parquet(uniquePaths.toArray(new String[uniquePaths.size()]));
StructType schema = originalDF.schema();
JavaPairRDD<HoodieKey, Row> keyRowRDD = originalDF.javaRDD()
.mapToPair(row -> {
HoodieKey key = new HoodieKey(
row.<String>getAs(HoodieRecord.RECORD_KEY_METADATA_FIELD),
row.<String>getAs(HoodieRecord.PARTITION_PATH_METADATA_FIELD));
return new Tuple2<>(key, row);
});
// Now, we need to further filter out, for only rows that match the supplied hoodie keys
JavaRDD<Row> rowRDD = keyRowRDD.join(keyToFileRDD, parallelism)
.map(tuple -> tuple._2()._1());
return sqlContextOpt.get().createDataFrame(rowRDD, schema);
}
/**
* Reads the paths under the a hoodie dataset out as a DataFrame
*/
public Dataset<Row> read(String... paths) {
assertSqlContext();
List<String> filteredPaths = new ArrayList<>();
TableFileSystemView fileSystemView = hoodieTable.getFileSystemView();
try {
for (String path : paths) {
if (!path.contains(hoodieTable.getMetaClient().getBasePath())) {
throw new HoodieException("Path " + path
+ " does not seem to be a part of a Hoodie dataset at base path "
+ hoodieTable.getMetaClient().getBasePath());
}
List<HoodieDataFile> latestFiles = fileSystemView.getLatestVersions(fs.globStatus(new Path(path))).collect(
Collectors.toList());
for (HoodieDataFile file : latestFiles) {
filteredPaths.add(file.getPath());
}
}
return sqlContextOpt.get().read()
.parquet(filteredPaths.toArray(new String[filteredPaths.size()]));
} catch (Exception e) {
throw new HoodieException("Error reading hoodie dataset as a dataframe", e);
}
}
/**
* Obtain all new data written into the Hoodie dataset since the given timestamp.
*
* If you made a prior call to {@link HoodieReadClient#latestCommit()}, it gives you all data in
* the time window (commitTimestamp, latestCommit)
*/
public Dataset<Row> readSince(String lastCommitTimestamp) {
List<HoodieInstant> commitsToReturn =
commitTimeline.findInstantsAfter(lastCommitTimestamp, Integer.MAX_VALUE)
.getInstants().collect(Collectors.toList());
//TODO: we can potentially trim this down to only affected partitions, using CommitMetadata
try {
// Go over the commit metadata, and obtain the new files that need to be read.
HashMap<String, String> fileIdToFullPath = new HashMap<>();
for (HoodieInstant commit : commitsToReturn) {
HoodieCommitMetadata metadata =
HoodieCommitMetadata.fromBytes(commitTimeline.getInstantDetails(commit).get());
// get files from each commit, and replace any previous versions
fileIdToFullPath.putAll(metadata.getFileIdAndFullPaths());
}
return sqlContextOpt.get().read()
.parquet(fileIdToFullPath.values().toArray(new String[fileIdToFullPath.size()]))
.filter(String.format("%s >'%s'", HoodieRecord.COMMIT_TIME_METADATA_FIELD, lastCommitTimestamp));
} catch (IOException e) {
throw new HoodieException("Error pulling data incrementally from commitTimestamp :" + lastCommitTimestamp, e);
}
}
/**
* Obtain
*/
public Dataset<Row> readCommit(String commitTime) {
assertSqlContext();
String actionType = hoodieTable.getCompactedCommitActionType();
HoodieInstant commitInstant =
new HoodieInstant(false, actionType, commitTime);
if (!commitTimeline.containsInstant(commitInstant)) {
new HoodieException("No commit exists at " + commitTime);
}
try {
HoodieCommitMetadata commitMetdata =
HoodieCommitMetadata.fromBytes(commitTimeline.getInstantDetails(commitInstant).get());
Collection<String> paths = commitMetdata.getFileIdAndFullPaths().values();
return sqlContextOpt.get().read()
.parquet(paths.toArray(new String[paths.size()]))
.filter(String.format("%s ='%s'", HoodieRecord.COMMIT_TIME_METADATA_FIELD, commitTime));
} catch (Exception e) {
throw new HoodieException("Error reading commit " + commitTime, e);
}
}
/**
* Checks if the given [Keys] exists in the hoodie table and returns [Key,
* Optional[FullFilePath]] If the optional FullFilePath value is not present, then the key is
* not found. If the FullFilePath value is present, it is the path component (without scheme) of
* the URI underlying file
*/
public JavaPairRDD<HoodieKey, Optional<String>> checkExists(JavaRDD<HoodieKey> hoodieKeys) {
return index.fetchRecordLocation(hoodieKeys, hoodieTable);
}
/**
* Filter out HoodieRecords that already exists in the output folder. This is useful in
* deduplication.
*
* @param hoodieRecords Input RDD of Hoodie records.
* @return A subset of hoodieRecords RDD, with existing records filtered out.
*/
public JavaRDD<HoodieRecord> filterExists(JavaRDD<HoodieRecord> hoodieRecords) {
JavaRDD<HoodieRecord> recordsWithLocation = index.tagLocation(hoodieRecords, hoodieTable);
return recordsWithLocation.filter(v1 -> !v1.isCurrentLocationKnown());
}
/**
* Checks if the Hoodie dataset has new data since given timestamp. This can be subsequently
* used to call {@link HoodieReadClient#readSince(String)} to perform incremental processing.
*/
public boolean hasNewCommits(String commitTimestamp) {
return listCommitsSince(commitTimestamp).size() > 0;
}
/**
*
* @param commitTimestamp
* @return
*/
public List<String> listCommitsSince(String commitTimestamp) {
return commitTimeline.findInstantsAfter(commitTimestamp, Integer.MAX_VALUE).getInstants()
.map(HoodieInstant::getTimestamp).collect(Collectors.toList());
}
/**
* Returns the last successful commit (a successful write operation) into a Hoodie table.
*/
public String latestCommit() {
return commitTimeline.lastInstant().get().getTimestamp();
}
}