TheNeuralBit commented on a change in pull request #12838: URL: https://github.com/apache/beam/pull/12838#discussion_r499086983
########## File path: sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/meta/provider/kafka/BeamKafkaProtoTable.java ########## @@ -0,0 +1,140 @@ +/* + * 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.extensions.sql.meta.provider.kafka; + +import com.google.protobuf.Message; +import java.io.ByteArrayInputStream; +import java.io.ByteArrayOutputStream; +import java.io.IOException; +import java.io.InputStream; +import java.util.List; +import org.apache.beam.sdk.extensions.protobuf.ProtoCoder; +import org.apache.beam.sdk.extensions.protobuf.ProtoMessageSchema; +import org.apache.beam.sdk.schemas.Schema; +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.SerializableFunction; +import org.apache.beam.sdk.values.KV; +import org.apache.beam.sdk.values.PCollection; +import org.apache.beam.sdk.values.Row; +import org.apache.beam.sdk.values.TypeDescriptor; + +public class BeamKafkaProtoTable<ProtoT extends Message> extends BeamKafkaTable { + private final transient Class<ProtoT> protoClass; + + public BeamKafkaProtoTable( + Schema beamSchema, String bootstrapServers, List<String> topics, Class<ProtoT> protoClass) { + super(beamSchema, bootstrapServers, topics); + this.protoClass = protoClass; Review comment: We should verify early that `beamSchema` and the schema inferred from `protoClass` by `ProtoSchemaRegistry` are equivalent. In theory we could also allow the table definition to omit the schema in the case, since it can be determined fully from the protoClass. ########## File path: sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/meta/provider/kafka/BeamKafkaProtoTable.java ########## @@ -0,0 +1,140 @@ +/* + * 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.extensions.sql.meta.provider.kafka; + +import com.google.protobuf.Message; +import java.io.ByteArrayInputStream; +import java.io.ByteArrayOutputStream; +import java.io.IOException; +import java.io.InputStream; +import java.util.List; +import org.apache.beam.sdk.extensions.protobuf.ProtoCoder; +import org.apache.beam.sdk.extensions.protobuf.ProtoMessageSchema; +import org.apache.beam.sdk.schemas.Schema; +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.SerializableFunction; +import org.apache.beam.sdk.values.KV; +import org.apache.beam.sdk.values.PCollection; +import org.apache.beam.sdk.values.Row; +import org.apache.beam.sdk.values.TypeDescriptor; + +public class BeamKafkaProtoTable<ProtoT extends Message> extends BeamKafkaTable { + private final transient Class<ProtoT> protoClass; + + public BeamKafkaProtoTable( + Schema beamSchema, String bootstrapServers, List<String> topics, Class<ProtoT> protoClass) { + super(beamSchema, bootstrapServers, topics); + this.protoClass = protoClass; + } + + @Override + protected BeamKafkaTable getTable() { + return this; + } + + @Override + public PTransform<PCollection<KV<byte[], byte[]>>, PCollection<Row>> getPTransformForInput() { + return new ProtoRecorderDecoder<>(schema, protoClass); + } + + @Override + public PTransform<PCollection<Row>, PCollection<KV<byte[], byte[]>>> getPTransformForOutput() { + return new ProtoRecorderEncoder<>(protoClass); + } + + /** A PTransform to convert {@code KV<byte[], byte[]>} to {@link Row}. */ + private static class ProtoRecorderDecoder<ProtoT extends Message> + extends PTransform<PCollection<KV<byte[], byte[]>>, PCollection<Row>> { + private final Schema schema; + private final ProtoCoder<ProtoT> protoCoder; + private final SerializableFunction<ProtoT, Row> toRowFunction; + + ProtoRecorderDecoder(Schema schema, Class<ProtoT> clazz) { + this.schema = schema; + this.protoCoder = ProtoCoder.of(clazz); + this.toRowFunction = new ProtoMessageSchema().toRowFunction(TypeDescriptor.of(clazz)); + } + + @Override + public PCollection<Row> expand(PCollection<KV<byte[], byte[]>> input) { + return input + .apply( + "decodeProtoRecord", + ParDo.of( + new DoFn<KV<byte[], byte[]>, Row>() { + @ProcessElement + public void processElement(ProcessContext c) { + Row decodedRow = decodeBytesToRow(c.element().getValue()); + c.output(decodedRow); + } + })) + .setRowSchema(schema); + } + + private Row decodeBytesToRow(byte[] bytes) { + try { + InputStream inputStream = new ByteArrayInputStream(bytes); + ProtoT message = protoCoder.decode(inputStream); + return toRowFunction.apply(message); + } catch (IOException e) { + throw new IllegalArgumentException("Could not decode row from proto payload.", e); + } + } + } + + /** A PTransform to convert {@link Row} to {@code KV<byte[], byte[]>}. */ + private static class ProtoRecorderEncoder<ProtoT extends Message> + extends PTransform<PCollection<Row>, PCollection<KV<byte[], byte[]>>> { + private final SerializableFunction<Row, ProtoT> toProtoFunction; + private final ProtoCoder<ProtoT> protoCoder; + private final Class<ProtoT> clazz; + + public ProtoRecorderEncoder(Class<ProtoT> clazz) { + this.protoCoder = ProtoCoder.of(clazz); + this.toProtoFunction = new ProtoMessageSchema().fromRowFunction(TypeDescriptor.of(clazz)); + this.clazz = clazz; + } + + @Override + public PCollection<KV<byte[], byte[]>> expand(PCollection<Row> input) { + return input.apply( + "encodeProtoRecord", + ParDo.of( + new DoFn<Row, KV<byte[], byte[]>>() { + @ProcessElement + public void processElement(ProcessContext c) { + Row row = c.element(); + c.output(KV.of(new byte[] {}, encodeRowToProtoBytes(row))); + } + })); + } + + byte[] encodeRowToProtoBytes(Row row) { + ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); + try { + Message message = toProtoFunction.apply(row); Review comment: There's the possibility for some subtle errors here because SQL's concept of the schema could have the fields in a different order than the order in the protobuf descriptor, lets make sure to test that case, and consider adding a step to "convert" between the protobuf-generated schema and the SQL schema when encoding and decoding. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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