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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Work logged] (BEAM-214) Create Parquet IO
Date Fri, 11 May 2018 20:17:00 GMT

     [ https://issues.apache.org/jira/browse/BEAM-214?focusedWorklogId=101292&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-101292
]

ASF GitHub Bot logged work on BEAM-214:
---------------------------------------

                Author: ASF GitHub Bot
            Created on: 11/May/18 20:16
            Start Date: 11/May/18 20:16
    Worklog Time Spent: 10m 
      Work Description: jkff commented on a change in pull request #5242: [BEAM-214] ParquetIO
URL: https://github.com/apache/beam/pull/5242#discussion_r187721225
 
 

 ##########
 File path: sdks/java/io/parquet/src/main/java/org/apache/beam/sdk/io/parquet/ParquetIO.java
 ##########
 @@ -0,0 +1,562 @@
+/*
+ * 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.beam.sdk.io.parquet;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+import static org.apache.parquet.hadoop.ParquetFileWriter.Mode.OVERWRITE;
+
+import com.google.auto.value.AutoValue;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.channels.Channels;
+import java.nio.channels.SeekableByteChannel;
+import java.nio.channels.WritableByteChannel;
+import javax.annotation.Nullable;
+import org.apache.avro.Schema;
+import org.apache.avro.generic.GenericRecord;
+import org.apache.beam.sdk.annotations.Experimental;
+import org.apache.beam.sdk.coders.AvroCoder;
+import org.apache.beam.sdk.coders.StringUtf8Coder;
+import org.apache.beam.sdk.io.FileIO;
+import org.apache.beam.sdk.io.FileSystems;
+import org.apache.beam.sdk.io.fs.EmptyMatchTreatment;
+import org.apache.beam.sdk.io.fs.MatchResult;
+import org.apache.beam.sdk.io.fs.ResourceId;
+import org.apache.beam.sdk.options.ValueProvider;
+import org.apache.beam.sdk.transforms.Create;
+import org.apache.beam.sdk.transforms.DoFn;
+import org.apache.beam.sdk.transforms.PTransform;
+import org.apache.beam.sdk.transforms.ParDo;
+import org.apache.beam.sdk.transforms.Watch;
+import org.apache.beam.sdk.transforms.display.DisplayData;
+import org.apache.beam.sdk.values.PBegin;
+import org.apache.beam.sdk.values.PCollection;
+import org.apache.beam.sdk.values.PDone;
+import org.apache.parquet.avro.AvroParquetReader;
+import org.apache.parquet.avro.AvroParquetWriter;
+import org.apache.parquet.hadoop.ParquetReader;
+import org.apache.parquet.hadoop.ParquetWriter;
+import org.apache.parquet.io.DelegatingSeekableInputStream;
+import org.apache.parquet.io.InputFile;
+import org.apache.parquet.io.OutputFile;
+import org.apache.parquet.io.PositionOutputStream;
+import org.apache.parquet.io.SeekableInputStream;
+import org.joda.time.Duration;
+
+/**
+ * IO to read and write Parquet files.
+ *
+ * <h3>Reading Parquet files</h3>
+ *
+ * <p>{@link ParquetIO} source returns a {@link PCollection} for
+ * Parquet files. The elements in the {@link PCollection} are Avro {@link GenericRecord}.
+ *
+ * <p>To configure the {@link Read}, you have to provide the file patterns (from) of
the
+ * Parquet files and the Avro schema.
+ *
+ * <p>For example:
+ *
+ * <pre>{@code
+ *  pipeline.apply(ParquetIO.read().from("/foo/bar").withSchema(schema))
+ *  ...
+ * }
+ * </pre>
+ *
+ * <p>As {@link Read} is based on {@link FileIO}, it supports any filesystem (hdfs,
...).
+ *
+ * <h3>Writing Parquet files</h3>
+ *
+ * <p>{@link Write} allows you to write a {@link PCollection} of {@link GenericRecord}
into a
+ * Parquet file.
+ *
+ * <p>For example:
+ *
+ * <pre>{@code
+ *  pipeline
+ *    .apply(...) // PCollection<GenericRecord>
+ *    .apply(ParquetIO.write().to("/foo/bar").withSchema(schema));
+ * }</pre>
+ */
+public class ParquetIO {
+
+  /**
+   * Reads {@link GenericRecord} from a Parquet file (or multiple Parquet files matching
+   * the pattern).
+   */
+  public static Read read() {
+    return new AutoValue_ParquetIO_Read.Builder().setHintMatchesManyFiles(false)
+        .setMatchConfiguration(FileIO.MatchConfiguration.create(EmptyMatchTreatment.DISALLOW))
+        .build();
+  }
+
+  /**
+   * Like {@link #read()}, but reads each filepattern in the input {@link PCollection}.
+   */
+  public static ReadAll readAll() {
+    return new AutoValue_ParquetIO_ReadAll.Builder()
+        .setMatchConfiguration(FileIO.MatchConfiguration
+            .create(EmptyMatchTreatment.ALLOW_IF_WILDCARD))
+        .build();
+  }
+
+  /**
+   * Like {@link #read()}, but reads each file in a {@link PCollection}
+   * of {@link org.apache.beam.sdk.io.FileIO.ReadableFile},
+   * which allows more flexible usage.
+   */
+  public static ReadFiles readFiles() {
+    return new AutoValue_ParquetIO_ReadFiles.Builder().build();
+  }
+
+  /**
+   * Writes a {@link PCollection} to an Parquet file.
+   */
+  public static Write write() {
+    return new AutoValue_ParquetIO_Write.Builder().build();
+  }
+
+  /**
+   * Implementation of {@link #read()}.
+   */
+  @AutoValue
+  public abstract static class Read extends PTransform<PBegin, PCollection<GenericRecord>>
{
+
+    @Nullable abstract ValueProvider<String> filepattern();
+    abstract FileIO.MatchConfiguration matchConfiguration();
+    @Nullable abstract Schema schema();
+    abstract boolean hintMatchesManyFiles();
+
+    abstract Builder builder();
+
+    @AutoValue.Builder
+    abstract static class Builder {
+      abstract Builder setFilepattern(ValueProvider<String> filepattern);
+      abstract Builder setMatchConfiguration(FileIO.MatchConfiguration matchConfiguration);
+      abstract Builder setSchema(Schema schema);
+      abstract Builder setHintMatchesManyFiles(boolean hintManyFiles);
+
+      abstract Read build();
+    }
+
+    /**
+     * Reads from the given filename or filepattern.
+     *
+     * <p>If it is known that the filepattern will match a very large number of files
(at least tens
+     * of thousands), use {@link #withHintMatchesManyFiles} for better performance and scalability.
+     */
+    public Read from(ValueProvider<String> filepattern) {
+      return builder().setFilepattern(filepattern).build();
+    }
+
+    /** Like {@link #from(ValueProvider)}. */
+    public Read from(String filepattern) {
+      return from(ValueProvider.StaticValueProvider.of(filepattern));
+    }
+
+    /**
+     * Schema of the record in the Parquet file.
+     */
+    public Read withSchema(Schema schema) {
+      return builder().setSchema(schema).build();
+    }
+
+    /** Sets the {@link FileIO.MatchConfiguration}. */
+    public Read withMatchConfiguration(FileIO.MatchConfiguration matchConfiguration) {
+      return builder().setMatchConfiguration(matchConfiguration).build();
+    }
+
+    /** Configures whether or not a filepattern matching no files is allowed. */
+    public Read withEmptyMatchTreatment(EmptyMatchTreatment treatment) {
+      return withMatchConfiguration(matchConfiguration().withEmptyMatchTreatment(treatment));
+    }
+
+    /**
+     * Continuously watches for new files matching the filepattern, polling it at the given
+     * interval, until the given termination condition is reached. The returned {@link PCollection}
+     * is unbounded.
+     *
+     * <p>This works only in runners supporting {@link Experimental.Kind#SPLITTABLE_DO_FN}.
+     */
+    @Experimental(Experimental.Kind.SPLITTABLE_DO_FN)
+    public Read watchForNewFiles(
+        Duration pollInterval, Watch.Growth.TerminationCondition<String, ?> terminationCondition)
{
+      return withMatchConfiguration(
+          matchConfiguration().continuously(pollInterval, terminationCondition));
+    }
+
+    /**
+     * Hints that the filepattern specified in {@link #from(String)} matches a very large
number of
+     * files.
+     *
+     * <p>This hint may cause a runner to execute the transform differently, in a way
that improves
+     * performance for this case, but it may worsen performance if the filepattern matches
only a
+     * small number of files (e.g., in a runner that supports dynamic work rebalancing, it
will
+     * happen less efficiently within individual files).
+     */
+    public Read withHintMatchesManyFiles() {
+      return builder().setHintMatchesManyFiles(true).build();
+    }
+
+    @Override
+    public PCollection<GenericRecord> expand(PBegin input) {
+      checkNotNull(filepattern(), "filepattern");
+      checkNotNull(schema(), "schema");
+
+      ReadAll readAll = readAll().withMatchConfiguration(matchConfiguration()).withSchema(schema());
+      return input
+          .apply("Create filepattern", Create.ofProvider(filepattern(),
+              StringUtf8Coder.of()))
+          .apply("Via ReadAll", readAll);
+    }
+
+    @Override
+    public void populateDisplayData(DisplayData.Builder builder) {
+      super.populateDisplayData(builder);
+      builder
+          .addIfNotNull(
+              DisplayData.item("filePattern", filepattern()).withLabel("Input File Pattern"))
+          .include("matchConfiguration", matchConfiguration());
+    }
+  }
+
+  /**
+   * Implementation of {@link #readAll()}.
+   */
+  @AutoValue
+  public abstract static class ReadAll extends PTransform<PCollection<String>,
+      PCollection<GenericRecord>> {
+
+    abstract FileIO.MatchConfiguration getMatchConfiguration();
+    @Nullable abstract Schema getSchema();
+
+    abstract Builder builder();
+
+    @AutoValue.Builder
+    abstract static class Builder {
+      abstract Builder setMatchConfiguration(FileIO.MatchConfiguration matchConfiguration);
+      abstract Builder setSchema(Schema schema);
+
+      abstract ReadAll build();
+    }
+
+    /**
+     * Sets the {@link org.apache.beam.sdk.io.FileIO.MatchConfiguration}.
+     */
+    public ReadAll withMatchConfiguration(FileIO.MatchConfiguration configuration) {
+      return builder().setMatchConfiguration(configuration).build();
+    }
+
+    /**
+     * Sets the {@link EmptyMatchTreatment}.
+     */
+    public ReadAll withEmptyMatchTreatment(EmptyMatchTreatment treatment) {
+      return withMatchConfiguration(getMatchConfiguration().withEmptyMatchTreatment(treatment));
+    }
+
+    /**
+     * Sets the schema of the records.
+     */
+    public ReadAll withSchema(Schema schema) {
+      return builder().setSchema(schema).build();
+    }
+
+    @Experimental(Experimental.Kind.SPLITTABLE_DO_FN)
+    public ReadAll watchForNewFiles(
+        Duration pollInterval, Watch.Growth.TerminationCondition<String, ?> terminationCondition)
{
+      return withMatchConfiguration(
+          getMatchConfiguration().continuously(pollInterval, terminationCondition));
+    }
+
+    @Override
+    public PCollection<GenericRecord> expand(PCollection<String> input) {
+      checkNotNull(getSchema(), "schema");
+      return input
+          .apply(FileIO.matchAll().withConfiguration(getMatchConfiguration()))
+          .apply(FileIO.readMatches())
+          .apply(readFiles().withSchema(getSchema()));
+    }
+
+    @Override
+    public void populateDisplayData(DisplayData.Builder builder) {
+      super.populateDisplayData(builder);
+      builder.include("matchConfiguration", getMatchConfiguration());
+    }
+
+  }
+
+  /**
+   * Implementation of {@link #readFiles()}.
+   */
+  @AutoValue
+  public abstract static class ReadFiles extends PTransform<PCollection<FileIO.ReadableFile>,
+      PCollection<GenericRecord>> {
+
+    @Nullable abstract Schema schema();
+
+    abstract Builder builder();
+
+    @AutoValue.Builder
+    abstract static class Builder {
+      abstract Builder setSchema(Schema schema);
+      abstract ReadFiles build();
+    }
+
+    /**
+     * Define the Avro schema of the record to read from the Parquet file.
+     */
+    public ReadFiles withSchema(Schema schema) {
+      checkArgument(schema != null,
+          "schema can not be null");
+      return builder().setSchema(schema).build();
+    }
+
+    @Override
+    public PCollection<GenericRecord> expand(PCollection<FileIO.ReadableFile>
input) {
+      return input
+          .apply(ParDo.of(new ReadFn()))
 
 Review comment:
   This means the reading of Parquet files will not be splittable, and it will be particularly
problematic in some streaming runners eg. Dataflow. It may be fine for a first version, but
is there a relatively easy way to make it splittable?

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Issue Time Tracking
-------------------

    Worklog Id:     (was: 101292)
    Time Spent: 7h 10m  (was: 7h)

> Create Parquet IO
> -----------------
>
>                 Key: BEAM-214
>                 URL: https://issues.apache.org/jira/browse/BEAM-214
>             Project: Beam
>          Issue Type: Improvement
>          Components: io-ideas
>            Reporter: Neville Li
>            Assignee: Jean-Baptiste Onofré
>            Priority: Minor
>          Time Spent: 7h 10m
>  Remaining Estimate: 0h
>
> Would be nice to support Parquet files with projection and predicates.



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