How to use Apache Flink write parquet file on HDFS by datetime partition?

Question

During ingest json data from kafka and save them as parquet files which be loaded into hive, I met the same issue mentioned in Flink BucketingSink with Custom AvroParquetWriter create empty file . Does anyone know how to resolve it? Thank you. I used Apache Flink 1.4.0 + HDFS 2.7.3

Answer 1

You can directly implement the Writer interface. It could look the following way:

import org.apache.flink.util.Preconditions;

import org.apache.avro.Schema;
import org.apache.avro.generic.GenericData;
import org.apache.avro.generic.GenericRecord;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.parquet.avro.AvroParquetWriter;
import org.apache.parquet.hadoop.ParquetWriter;
import org.apache.parquet.hadoop.metadata.CompressionCodecName;

import java.io.IOException;

/**
 * Parquet writer.
 *
 * @param <T>
 */
public class ParquetSinkWriter<T extends GenericRecord> implements Writer<T> {

    private static final long serialVersionUID = -975302556515811398L;

    private final CompressionCodecName compressionCodecName = CompressionCodecName.SNAPPY;
    private final int pageSize = 64 * 1024;

    private final String schemaRepresentation;

    private transient Schema schema;
    private transient ParquetWriter<GenericRecord> writer;
    private transient Path path;

    private int position;

    public ParquetSinkWriter(String schemaRepresentation) {
        this.schemaRepresentation = Preconditions.checkNotNull(schemaRepresentation);
    }

    @Override
    public void open(FileSystem fs, Path path) throws IOException {
        this.position = 0;
        this.path = path;

        if (writer != null) {
            writer.close();
        }

        writer = createWriter();
    }

    @Override
    public long flush() throws IOException {
        Preconditions.checkNotNull(writer);
        position += writer.getDataSize();
        writer.close();
        writer = createWriter();

        return position;
    }

    @Override
    public long getPos() throws IOException {
        Preconditions.checkNotNull(writer);
        return position + writer.getDataSize();
    }

    @Override
    public void close() throws IOException {
        if (writer != null) {
            writer.close();
            writer = null;
        }
    }

    @Override
    public void write(T element) throws IOException {
        Preconditions.checkNotNull(writer);
        writer.write(element);
    }

    @Override
    public Writer<T> duplicate() {
        return new ParquetSinkWriter<>(schemaRepresentation);
    }

    private ParquetWriter<GenericRecord> createWriter() throws IOException {
        if (schema == null) {
            schema = new Schema.Parser().parse(schemaRepresentation);
        }

        return AvroParquetWriter.<GenericRecord>builder(path)
            .withSchema(schema)
            .withDataModel(new GenericData())
            .withCompressionCodec(compressionCodecName)
            .withPageSize(pageSize)
            .build();
    }
}