mattcasters commented on a change in pull request #15916: URL: https://github.com/apache/beam/pull/15916#discussion_r745678492
########## File path: sdks/java/io/neo4j/src/main/java/org/apache/beam/sdk/io/neo4j/Neo4jIO.java ########## @@ -0,0 +1,1358 @@ +/* + * 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.neo4j; + +import static org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkArgument; + +import com.google.auto.value.AutoValue; +import java.io.Serializable; +import java.net.URI; +import java.net.URISyntaxException; +import java.time.Duration; +import java.util.ArrayList; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.TimeUnit; +import java.util.logging.Level; +import org.apache.beam.repackaged.core.org.apache.commons.lang3.StringUtils; +import org.apache.beam.sdk.annotations.Experimental; +import org.apache.beam.sdk.coders.Coder; +import org.apache.beam.sdk.harness.JvmInitializer; +import org.apache.beam.sdk.options.ValueProvider; +import org.apache.beam.sdk.schemas.NoSuchSchemaException; +import org.apache.beam.sdk.schemas.Schema; +import org.apache.beam.sdk.schemas.SchemaRegistry; +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.transforms.display.DisplayData; +import org.apache.beam.sdk.transforms.display.HasDisplayData; +import org.apache.beam.sdk.values.PCollection; +import org.apache.beam.sdk.values.PDone; +import org.apache.beam.sdk.values.TypeDescriptor; +import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions; +import org.checkerframework.checker.nullness.qual.Nullable; +import org.neo4j.driver.AuthTokens; +import org.neo4j.driver.Config; +import org.neo4j.driver.Driver; +import org.neo4j.driver.GraphDatabase; +import org.neo4j.driver.Logging; +import org.neo4j.driver.Record; +import org.neo4j.driver.Result; +import org.neo4j.driver.Session; +import org.neo4j.driver.SessionConfig; +import org.neo4j.driver.TransactionConfig; +import org.neo4j.driver.TransactionWork; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * This is a Beam IO to read from, and write data to, Neo4j. + * + * <p> + * + * <p> + * + * <h3>Driver configuration</h3> + * + * <p>To read from or write to Neo4j you have to provide a {@link DriverConfiguration} using<br> + * 1. {@link DriverConfiguration#create()} (which must be {@link Serializable});<br> + * 2. or {@link DriverConfiguration#create(String, String, String)} (URL, username and password). + * + * <p>If you have trouble connecting to a Neo4j Aura database please try to disable a few security + * algorithms in your JVM. This makes sure that the right one is picked to connect: + * + * <p> + * + * <pre>{@code + * Security.setProperty( + * "jdk.tls.disabledAlgorithms", + * "SSLv3, RC4, DES, MD5withRSA, DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL"); + * }</pre> + * + * <p> + * + * <p> + * + * <p>To execute this code on GCP Dataflow you can create a class which extends {@link + * JvmInitializer} and implement the {@link JvmInitializer#onStartup()} method. You need to annotate + * this new class with {@link com.google.auto.service.AutoService} + * + * <pre>{@code + * @AutoService(value = JvmInitializer.class) + * }</pre> + * + * <p> + * + * <h3>Reading from Neo4j</h3> + * + * <p>{@link Neo4jIO#read()} source returns a bounded collection of {@code OuptutT} as a {@code + * PCollection<OutputT>}. OutputT is the type returned by the provided {@link RowMapper}. It accepts + * parameters as input in the form of {@code ParameterT} as a {@code PCollection<ParameterT>} + * + * <p>The following example reads ages to return the IDs of Person nodes. It runs a Cypher query for + * each provided age. + * + * <p>The {@link ParametersMapper} maps input values to each execution of the Cypher statement. + * These parameter values are stored in a {@link Map} (mapping String to Object). The map is cleared + * after each execution. + * + * <p>The {@link RowMapper} converts output Neo4j {@link Record} values to the output of the source. + * + * <pre>{@code + * pipeline.apply( Neo4jIO.<Integer, String>read() + * .withDriverConfiguration(Neo4jIO.DriverConfiguration.create("neo4j://localhost:7687", "neo4j", "password")) + * .withCypher("MATCH(n:Person) WHERE n.age = $age RETURN n.id") + * .withReadTransaction() + * .withCoder(StringUtf8Coder.of()) + * .withParametersMapper((age, rowMap) -> rowMap.put("age", age)) + * .withRowMapper( record -> return record.get(0).asString() ) + * ); + * }</pre> + * + * <h3>Writing to Neo4j</h3> + * + * <p>Neo4j sink supports writing data to a graph. It writes a {@link PCollection} to the graph by + * collecting a batch of rows after which all rows in this batch are written together to Neo4j. This + * is done using the {@link WriteUnwind} sink transform. + * + * <p>Like the source, to configure the sink, you have to provide a {@link DriverConfiguration}. + * + * <p>In the following example we'll merge a collection of {@link org.apache.beam.sdk.values.Row} + * into Person nodes. Since this is a Sink it has no output and as such no RowMapper is needed. The + * rows are being used as a container for the parameters of the Cypher statement. The used Cypher in + * question needs to be an UNWIND statement. Like in the read case, the {@link ParametersMapper} + * maps values to a {@link Map<String, Object>}. The difference is that the resulting Map is stored + * in a {@link List} (containing maps) which in turn is stored in another Map under the name + * provided by the {@link WriteUnwind#withUnwindMapName(String)} method. All of this is handled + * automatically. You do need to provide the unwind map name so that you can reference that in the + * UNWIND statement. + * + * <p> + * + * <p>For example: + * + * <pre>{@code + * pipeline + * .apply(...) + * .apply(Neo4jIO.<Row>writeUnwind() + * .withDriverConfiguration(Neo4jIO.DriverConfiguration.create("neo4j://localhost:7687", "neo4j", "password")) + * .withUnwindMapName("rows") + * .withCypher("UNWIND $rows AS row MERGE(n:Person { id : row.id } ) SET n.firstName = row.first, n.lastName = row.last") + * .withParametersMapper( (row, map ) -> { + * map.put("id", row.getString("id)); + * map.put("first", row.getString("firstName")); + * map.put("last", row.getString("lastName")); + * }) + * ); + * }</pre> + */ +@Experimental(Experimental.Kind.SOURCE_SINK) +public class Neo4jIO { + + private static final Logger LOG = LoggerFactory.getLogger(Neo4jIO.class); + + /** + * Read all rows using a Neo4j Cypher query. + * + * @param <ParameterT> Type of the data representing query parameters. + * @param <OutputT> Type of the data to be read. + */ + public static <ParameterT, OutputT> Read<ParameterT, OutputT> read() { + return new AutoValue_Neo4jIO_Read.Builder<ParameterT, OutputT>() + .setFetchSize(ValueProvider.StaticValueProvider.of(Config.defaultConfig().fetchSize())) + .build(); + } + + /** + * Write all rows using a Neo4j Cypher UNWIND cypher statement. This sets a default batch batch + * size of 5000. + * + * @param <ParameterT> Type of the data representing query parameters. + */ + public static <ParameterT> WriteUnwind<ParameterT> writeUnwind() { + return new AutoValue_Neo4jIO_WriteUnwind.Builder<ParameterT>() + .setBatchSize(ValueProvider.StaticValueProvider.of(5000L)) + .build(); + } + + private static <ParameterT, OutputT> PCollection<OutputT> getOutputPCollection( + PCollection<ParameterT> input, DoFn<ParameterT, OutputT> writeFn, Coder<OutputT> coder) { + PCollection<OutputT> output = input.apply(ParDo.of(writeFn)).setCoder(coder); + + try { + TypeDescriptor<OutputT> typeDesc = coder.getEncodedTypeDescriptor(); + SchemaRegistry registry = input.getPipeline().getSchemaRegistry(); + Schema schema = registry.getSchema(typeDesc); + output.setSchema( + schema, + typeDesc, + registry.getToRowFunction(typeDesc), + registry.getFromRowFunction(typeDesc)); + } catch (NoSuchSchemaException e) { + // ignore + } + return output; + } + + /** + * An interface used by {@link Read} for converting each row of a Neo4j {@link Result} record + * {@link Record} into an element of the resulting {@link PCollection}. + */ + @FunctionalInterface + public interface RowMapper<T> extends Serializable { + T mapRow(Record record) throws Exception; + } + + /** + * An interface used by {@link Read} for converting input parameter data to a parameters map which + * can be used by your Neo4j cypher query. + */ + @FunctionalInterface + public interface ParametersMapper<ParameterT> extends Serializable { + /** + * Simply map an input record to a parameters map. + * + * @param input the input read + * @param parametersMap the parameters map to update in this llabmda + */ + void mapParameters(ParameterT input, Map<String, Object> parametersMap); Review comment: The recommended change from ParametersMapper to SerializableFunction was done in commit [a257cec](https://github.com/apache/beam/pull/15916/commits/a257ceced20d132f7a10e3ebcbd260f7b0fb4a2d) -- This is an automated message from the Apache Git Service. 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