chamikaramj commented on a change in pull request #15916: URL: https://github.com/apache/beam/pull/15916#discussion_r783308658
########## File path: sdks/java/io/neo4j/src/main/java/org/apache/beam/sdk/io/neo4j/Neo4jIO.java ########## @@ -0,0 +1,1221 @@ +/* + * 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.util.ArrayList; +import java.util.Collections; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.concurrent.atomic.AtomicBoolean; +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.initialization.qual.Initialized; +import org.checkerframework.checker.nullness.qual.NonNull; +import org.checkerframework.checker.nullness.qual.Nullable; +import org.neo4j.driver.AuthToken; +import org.neo4j.driver.AuthTokens; +import org.neo4j.driver.Config; +import org.neo4j.driver.Driver; +import org.neo4j.driver.GraphDatabase; +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> + * {@link DriverConfiguration#create()} or {@link DriverConfiguration#create(String, String, + * String)} (URL, username and password). Note that subclasses of DriverConfiguration must also be + * {@link Serializable}). <br> + * At the level of the Neo4j driver configuration you can specify a Neo4j {@link Config} object with + * {@link DriverConfiguration#withConfig(Config)}. This way you can configure the Neo4j driver + * characteristics. Likewise, you can control the characteristics of Neo4j sessions by optionally + * passing a {@link SessionConfig} object to {@link ReadAll} or {@link WriteUnwind}. For example, + * the session configuration will allow you to target a specific database or set a fetch size. + * Finally, in even rarer cases you might need to configure the various aspects of Neo4j + * transactions, for example their timeout. You can do this with a Neo4j {@link TransactionConfig} + * object. + * + * <p> + * + * <p> + * + * <h3>Neo4j Aura</h3> + * + * <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#readAll()} 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 mapping {@link SerializableFunction} maps input values to each execution of the Cypher + * statement. In the function simply return a map containing the parameters you want to set. + * + * <p>The {@link RowMapper} converts output Neo4j {@link Record} values to the output of the source. + * + * <pre>{@code + * pipeline + * .apply(Create.of(40, 50, 60)) + * .apply(Neo4jIO.<Integer, String>readAll() + * .withDriverConfiguration(Neo4jIO.DriverConfiguration.create("neo4j://localhost:7687", "neo4j", "password")) + * .withCypher("MATCH(n:Person) WHERE n.age = $age RETURN n.id") + * .withReadTransaction() + * .withCoder(StringUtf8Coder.of()) + * .withParametersFunction( age -> Collections.singletonMap( "age", age )) + * .withRowMapper( record -> return record.get(0).asString() ) + * ); + * }</pre> + * + * <h3>Writing to Neo4j</h3> + * + * <p>The Neo4j {@link WriteUnwind} transform supports writing data to a graph. It writes a {@link + * PCollection} to the graph by collecting a batch of elements after which all elements in the batch + * are written together to Neo4j. + * + * <p>Like the source, to configure this 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 parameters {@link + * SerializableFunction} converts parameter values to a {@link Map}. The difference here 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") + * .withParametersFunction( row -> ImmutableMap.of( + * "id", row.getString("id), + * "first", row.getString("firstName") + * "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> ReadAll<ParameterT, OutputT> readAll() { + return new AutoValue_Neo4jIO_ReadAll.Builder<ParameterT, OutputT>().build(); + } + + /** + * Write all rows using a Neo4j Cypher UNWIND cypher statement. This sets a default 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, + @Nullable Coder<OutputT> coder) { + PCollection<OutputT> output = input.apply(ParDo.of(writeFn)); + if (coder != null) { + output.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 ReadAll} 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; + } + + /** + * A convenience method to clarify the way {@link ValueProvider} works to the static code checker + * framework for {@link Nullable} values. + * + * @param valueProvider + * @param <T> + * @return The provided value or null if none was specified. + */ + private static <T> T getProvidedValue(@Nullable ValueProvider<T> valueProvider) { + if (valueProvider == null) { + return (T) null; + } + return valueProvider.get(); + } + + /** This describes all the information needed to create a Neo4j {@link Session}. */ + @AutoValue + public abstract static class DriverConfiguration implements Serializable { + public static DriverConfiguration create() { + return new AutoValue_Neo4jIO_DriverConfiguration.Builder() + .build() + .withDefaultConfig(true) + .withConfig(Config.defaultConfig()); + } + + public static DriverConfiguration create(String url, String username, String password) { + checkArgument(url != null, "url can not be null"); + checkArgument(username != null, "username can not be null"); + checkArgument(password != null, "password can not be null"); + return new AutoValue_Neo4jIO_DriverConfiguration.Builder() + .build() + .withDefaultConfig(true) + .withConfig(Config.defaultConfig()) + .withUrl(url) + .withUsername(username) + .withPassword(password); + } + + abstract @Nullable ValueProvider<String> getUrl(); + + abstract @Nullable ValueProvider<List<String>> getUrls(); + + abstract @Nullable ValueProvider<String> getUsername(); + + abstract @Nullable ValueProvider<String> getPassword(); + + abstract @Nullable Config getConfig(); + + abstract @Nullable ValueProvider<Boolean> getHasDefaultConfig(); + + abstract Builder builder(); + + public DriverConfiguration withUrl(String url) { + return withUrl(ValueProvider.StaticValueProvider.of(url)); + } + + public DriverConfiguration withUrl(ValueProvider<String> url) { + Preconditions.checkArgument( + url != null, "a neo4j connection URL can not be empty or null", url); + Preconditions.checkArgument( + StringUtils.isNotEmpty(url.get()), + "a neo4j connection URL can not be empty or null", + url); + return builder().setUrl(url).build(); + } + + public DriverConfiguration withUrls(List<String> urls) { + return withUrls(ValueProvider.StaticValueProvider.of(urls)); + } + + public DriverConfiguration withUrls(ValueProvider<List<String>> urls) { + Preconditions.checkArgument( + urls != null, "a list of neo4j connection URLs can not be empty or null", urls); + Preconditions.checkArgument( + urls.get() != null && !urls.get().isEmpty(), + "a neo4j connection URL can not be empty or null", + urls); + return builder().setUrls(urls).build(); + } + + public DriverConfiguration withConfig(Config config) { + return builder().setConfig(config).build(); + } + + public DriverConfiguration withUsername(String username) { + return withUsername(ValueProvider.StaticValueProvider.of(username)); + } + + public DriverConfiguration withUsername(ValueProvider<String> username) { + Preconditions.checkArgument(username != null, "neo4j username can not be null", username); + Preconditions.checkArgument( + username.get() != null, "neo4j username can not be null", username); + return builder().setUsername(username).build(); + } + + public DriverConfiguration withPassword(String password) { + return withPassword(ValueProvider.StaticValueProvider.of(password)); + } + + public DriverConfiguration withPassword(ValueProvider<String> password) { + Preconditions.checkArgument(password != null, "neo4j password can not be null", password); + Preconditions.checkArgument( + password.get() != null, "neo4j password can not be null", password); + return builder().setPassword(password).build(); + } + + public DriverConfiguration withDefaultConfig(boolean useDefault) { + return withDefaultConfig(ValueProvider.StaticValueProvider.of(useDefault)); + } + + public DriverConfiguration withDefaultConfig(ValueProvider<Boolean> useDefault) { + Preconditions.checkArgument( + useDefault != null, "withDefaultConfig parameter useDefault can not be null", useDefault); + Preconditions.checkArgument( + useDefault.get() != null, + "withDefaultConfig parameter useDefault can not be null", + useDefault); + return builder().setHasDefaultConfig(useDefault).build(); + } + + void populateDisplayData(DisplayData.Builder builder) { + builder.addIfNotNull(DisplayData.item("neo4j-url", getUrl())); + builder.addIfNotNull(DisplayData.item("neo4j-username", getUsername())); + builder.addIfNotNull( + DisplayData.item( + "neo4j-password", getPassword() != null ? "<provided>" : "<not-provided>")); + } + + Driver buildDriver() { + // Create the Neo4j Driver + // This uses the provided Neo4j configuration along with URLs, username and password + // + Config config = getConfig(); + if (config == null) { + throw new RuntimeException("please provide a neo4j config"); + } + // We're trying to work around a subtle serialisation bug in the Neo4j Java driver. + // The fix is work in progress. For now, we harden our code to avoid + // wild goose chases. + // + Boolean hasDefaultConfig = getProvidedValue(getHasDefaultConfig()); + if (hasDefaultConfig != null && hasDefaultConfig) { + config = Config.defaultConfig(); + } + + // Get the list of the URI to connect with + // + List<URI> uris = new ArrayList<>(); + String url = getProvidedValue(getUrl()); + if (url != null) { + try { + uris.add(new URI(url)); + } catch (URISyntaxException e) { + throw new RuntimeException("Error creating URI from URL '" + url + "'", e); + } + } + List<String> providedUrls = getProvidedValue(getUrls()); + if (providedUrls != null) { + for (String providedUrl : providedUrls) { + try { + uris.add(new URI(providedUrl)); + } catch (URISyntaxException e) { + throw new RuntimeException( + "Error creating URI '" + + providedUrl + + "' from a list of " + + providedUrls.size() + + " URLs", + e); + } + } + } + + // A specific routing driver can be used to connect to specific clustered configurations. + // Often we don't need it because the Java driver automatically can figure this out + // automatically. To keep things simple we use the routing driver in case we have more + // than one URL specified. This is an exceptional case. + // + Driver driver; + AuthToken authTokens = + getAuthToken(getProvidedValue(getUsername()), getProvidedValue(getPassword())); + if (uris.size() > 1) { + driver = GraphDatabase.routingDriver(uris, authTokens, config); + } else { + // Just take the first URI that was provided + driver = GraphDatabase.driver(uris.get(0), authTokens, config); + } + + return driver; + } + + /** + * Certain embedded scenarios and so on actually allow for having no authentication at all. + * + * @param username The username if one is needed + * @param password The password if one is needed + * @return The AuthToken + */ + protected AuthToken getAuthToken(String username, String password) { + if (username != null && password != null) { + return AuthTokens.basic(username, password); + } else { + return AuthTokens.none(); + } + } + + /** + * The Builder class below is not visible. We use it to service the "with" methods below the + * Builder class. + */ + @AutoValue.Builder + abstract static class Builder { + abstract Builder setUrl(ValueProvider<String> url); + + abstract Builder setUrls(ValueProvider<List<String>> url); + + abstract Builder setUsername(ValueProvider<String> username); + + abstract Builder setPassword(ValueProvider<String> password); + + abstract Builder setConfig(Config config); + + abstract Builder setHasDefaultConfig(ValueProvider<Boolean> useDefault); + + abstract DriverConfiguration build(); + } + } + + /** This is the class which handles the work behind the {@link #readAll} method. */ + @AutoValue + public abstract static class ReadAll<ParameterT, OutputT> + extends PTransform<PCollection<ParameterT>, PCollection<OutputT>> { + + abstract @Nullable SerializableFunction<Void, Driver> getDriverProviderFn(); + + abstract @Nullable SessionConfig getSessionConfig(); + + abstract @Nullable TransactionConfig getTransactionConfig(); + + abstract @Nullable ValueProvider<String> getCypher(); + + abstract @Nullable ValueProvider<Boolean> getWriteTransaction(); + + abstract @Nullable RowMapper<OutputT> getRowMapper(); + + abstract @Nullable SerializableFunction<ParameterT, Map<String, Object>> + getParametersFunction(); + + abstract @Nullable Coder<OutputT> getCoder(); + + abstract @Nullable ValueProvider<Boolean> getLogCypher(); + + abstract Builder<ParameterT, OutputT> toBuilder(); + + public ReadAll<ParameterT, OutputT> withDriverConfiguration(DriverConfiguration config) { + return toBuilder() + .setDriverProviderFn(new DriverProviderFromDriverConfiguration(config)) + .build(); + } + + public ReadAll<ParameterT, OutputT> withCypher(String cypher) { + checkArgument( + cypher != null, "Neo4jIO.readAll().withCypher(query) called with null cypher query"); + return withCypher(ValueProvider.StaticValueProvider.of(cypher)); + } + + public ReadAll<ParameterT, OutputT> withCypher(ValueProvider<String> cypher) { + checkArgument(cypher != null, "Neo4jIO.readAll().withCypher(cypher) called with null cypher"); + return toBuilder().setCypher(cypher).build(); + } + + public ReadAll<ParameterT, OutputT> withSessionConfig(SessionConfig sessionConfig) { + checkArgument( + sessionConfig != null, + "Neo4jIO.readAll().withSessionConfig(sessionConfig) called with null sessionConfig"); + return toBuilder().setSessionConfig(sessionConfig).build(); + } + + public ReadAll<ParameterT, OutputT> withTransactionConfig(TransactionConfig transactionConfig) { + checkArgument( + transactionConfig != null, + "Neo4jIO.readAll().withTransactionConfig(transactionConfig) called with null transactionConfig"); + return toBuilder().setTransactionConfig(transactionConfig).build(); + } + + public ReadAll<ParameterT, OutputT> withRowMapper(RowMapper<OutputT> rowMapper) { + checkArgument( + rowMapper != null, + "Neo4jIO.readAll().withRowMapper(rowMapper) called with null rowMapper"); + return toBuilder().setRowMapper(rowMapper).build(); + } + + public ReadAll<ParameterT, OutputT> withParametersFunction( + SerializableFunction<ParameterT, Map<String, Object>> parametersFunction) { + checkArgument( + parametersFunction != null, + "Neo4jIO.readAll().withParametersFunction(parametersFunction) called with null parametersFunction"); + return toBuilder().setParametersFunction(parametersFunction).build(); + } + + public ReadAll<ParameterT, OutputT> withCoder(Coder<OutputT> coder) { + checkArgument(coder != null, "Neo4jIO.readAll().withCoder(coder) called with null coder"); + return toBuilder().setCoder(coder).build(); + } + + public ReadAll<ParameterT, OutputT> withReadTransaction() { + return toBuilder() + .setWriteTransaction(ValueProvider.StaticValueProvider.of(Boolean.FALSE)) + .build(); + } + + public ReadAll<ParameterT, OutputT> withWriteTransaction() { + return toBuilder() + .setWriteTransaction(ValueProvider.StaticValueProvider.of(Boolean.TRUE)) + .build(); + } + + public ReadAll<ParameterT, OutputT> withCypherLogging() { + return toBuilder().setLogCypher(ValueProvider.StaticValueProvider.of(Boolean.TRUE)).build(); + } + + @Override + public PCollection<OutputT> expand(PCollection<ParameterT> input) { + + final SerializableFunction<Void, Driver> driverProviderFn = getDriverProviderFn(); + final RowMapper<OutputT> rowMapper = getRowMapper(); + SerializableFunction<ParameterT, Map<String, Object>> parametersFunction = + getParametersFunction(); + + final String cypher = getProvidedValue(getCypher()); + checkArgument(cypher != null, "please provide a cypher statement to execute"); + + SessionConfig sessionConfig = getSessionConfig(); + if (sessionConfig == null) { + // Create a default session configuration as recommended by Neo4j + // + sessionConfig = SessionConfig.defaultConfig(); + } + + TransactionConfig transactionConfig = getTransactionConfig(); + if (transactionConfig == null) { + transactionConfig = TransactionConfig.empty(); + } + + Boolean writeTransaction = getProvidedValue(getWriteTransaction()); + if (writeTransaction == null) { + writeTransaction = Boolean.FALSE; + } + + Boolean logCypher = getProvidedValue(getLogCypher()); + if (logCypher == null) { + logCypher = Boolean.FALSE; + } + + if (driverProviderFn == null) { + throw new RuntimeException("please provide a driver provider"); + } + if (rowMapper == null) { + throw new RuntimeException("please provide a row mapper"); + } + if (parametersFunction == null) { + parametersFunction = t -> Collections.emptyMap(); + } + + ReadFn<ParameterT, OutputT> readFn = + new ReadFn<>( + driverProviderFn, + sessionConfig, + transactionConfig, + cypher, + rowMapper, + parametersFunction, + writeTransaction, + logCypher); + + return getOutputPCollection(input, readFn, getCoder()); + } + + @Override + public void populateDisplayData(DisplayData.Builder builder) { + super.populateDisplayData(builder); + String cypher = getProvidedValue(getCypher()); + if (cypher == null) { + cypher = ""; + } + builder.add(DisplayData.item("cypher", cypher)); + SerializableFunction<Void, Driver> driverProviderFn = getDriverProviderFn(); + if (driverProviderFn != null) { + if (driverProviderFn instanceof HasDisplayData) { + ((HasDisplayData) driverProviderFn).populateDisplayData(builder); + } + } + } + + @AutoValue.Builder + abstract static class Builder<ParameterT, OutputT> { + abstract Builder<ParameterT, OutputT> setDriverProviderFn( + SerializableFunction<Void, Driver> driverProviderFn); + + abstract Builder<ParameterT, OutputT> setCypher(ValueProvider<String> cypher); + + abstract Builder<ParameterT, OutputT> setSessionConfig(SessionConfig sessionConfig); + + abstract Builder<ParameterT, OutputT> setTransactionConfig( + TransactionConfig transactionConfig); + + abstract Builder<ParameterT, OutputT> setWriteTransaction( + ValueProvider<Boolean> writeTransaction); + + abstract Builder<ParameterT, OutputT> setRowMapper(RowMapper<OutputT> rowMapper); + + abstract Builder<ParameterT, OutputT> setParametersFunction( + SerializableFunction<ParameterT, Map<String, Object>> parametersFunction); + + abstract Builder<ParameterT, OutputT> setCoder(Coder<OutputT> coder); + + abstract Builder<ParameterT, OutputT> setLogCypher(ValueProvider<Boolean> logCypher); + + abstract ReadAll<ParameterT, OutputT> build(); + } + } + + /** A {@link DoFn} to execute a Cypher query to read from Neo4j. */ + private static class ReadWriteFn<ParameterT, OutputT> extends DoFn<ParameterT, OutputT> { + protected static class DriverSession { + public @Nullable Driver driver; + public @Nullable Session session; + public @NonNull AtomicBoolean closed; + + protected DriverSession(Driver driver, Session session) { + this.driver = driver; + this.session = session; + this.closed = new AtomicBoolean(false); + } + + private DriverSession() { + this.driver = null; + this.session = null; + this.closed = new AtomicBoolean(true); + } + + protected static @NonNull DriverSession emptyClosed() { + return new DriverSession(); + } + } + + protected final @NonNull SerializableFunction<Void, Driver> driverProviderFn; + protected final @NonNull SessionConfig sessionConfig; + protected final @NonNull TransactionConfig transactionConfig; + + protected transient @NonNull DriverSession driverSession; + + protected ReadWriteFn( + @NonNull SerializableFunction<Void, Driver> driverProviderFn, + @NonNull SessionConfig sessionConfig, + @NonNull TransactionConfig transactionConfig) { + this.driverProviderFn = driverProviderFn; + this.sessionConfig = sessionConfig; + this.transactionConfig = transactionConfig; + this.driverSession = DriverSession.emptyClosed(); + } + + /** + * Delay the creation of driver and session until we actually have data to do something with. + */ + @Setup + public void setup() {} + + protected @NonNull Driver createDriver() { + Driver driver = driverProviderFn.apply(null); + if (driver == null) { + throw new RuntimeException("null driver given by driver provider"); + } + return driver; + } + + protected @Initialized @NonNull DriverSession buildDriverSession() { + @NonNull Driver driver = createDriver(); + @NonNull Session session = driver.session(sessionConfig); + return new DriverSession(driver, session); + } + + @StartBundle + public void startBundle() { + if (driverSession == null || driverSession.closed.get()) { + driverSession = buildDriverSession(); + } + } + + @FinishBundle + public void finishBundle() { + cleanUpDriverSession(); + } + + @Override + protected void finalize() { + cleanUpDriverSession(); + } + + protected void cleanUpDriverSession() { + if (!driverSession.closed.get()) { + try { + if (driverSession.session != null) { + driverSession.session.close(); + } + if (driverSession.driver != null) { + driverSession.driver.close(); + } + } finally { + driverSession.closed.set(true); + } + } + } + + protected String getParametersString(Map<String, Object> parametersMap) { + StringBuilder parametersString = new StringBuilder(); + parametersMap + .keySet() + .forEach( + key -> { + if (parametersString.length() > 0) { + parametersString.append(','); + } + parametersString.append(key).append('='); + Object value = parametersMap.get(key); + if (value == null) { + parametersString.append("<null>"); + } else { + parametersString.append(value); + } + }); + return parametersString.toString(); + } + } + + /** A {@link DoFn} to execute a Cypher query to read from Neo4j. */ + private static class ReadFn<ParameterT, OutputT> extends ReadWriteFn<ParameterT, OutputT> { + protected final @NonNull String cypher; + protected final @NonNull RowMapper<OutputT> rowMapper; + protected final @Nullable SerializableFunction<ParameterT, Map<String, Object>> + parametersFunction; + + private final boolean writeTransaction; + private final boolean logCypher; + + private ReadFn( + @NonNull SerializableFunction<Void, Driver> driverProviderFn, + @NonNull SessionConfig sessionConfig, + @NonNull TransactionConfig transactionConfig, + @NonNull String cypher, + @NonNull RowMapper<OutputT> rowMapper, + @Nullable SerializableFunction<ParameterT, Map<String, Object>> parametersFunction, + boolean writeTransaction, + boolean logCypher) { + super(driverProviderFn, sessionConfig, transactionConfig); + this.cypher = cypher; + this.rowMapper = rowMapper; + this.parametersFunction = parametersFunction; + this.writeTransaction = writeTransaction; + this.logCypher = logCypher; + } + + @ProcessElement + public void processElement(ProcessContext context) { + // Map the input data to the parameters map... + // + ParameterT parameters = context.element(); + final Map<String, Object> parametersMap; + if (parametersFunction != null) { + parametersMap = parametersFunction.apply(parameters); + } else { + parametersMap = Collections.emptyMap(); + } + executeReadCypherStatement(context, parametersMap); + } + + private void executeReadCypherStatement( + final ProcessContext processContext, Map<String, Object> parametersMap) { + // The actual "reading" work needs to happen in a transaction. + // We could actually read and write here depending on the type of transaction + // we picked. As long as the Cypher statement returns values it's fine. + // + TransactionWork<Void> transactionWork = + transaction -> { + Result result = transaction.run(cypher, parametersMap); + while (result.hasNext()) { + Record record = result.next(); + try { + OutputT outputT = rowMapper.mapRow(record); + processContext.output(outputT); + } catch (Exception e) { + throw new RuntimeException("error mapping Neo4j record to row", e); + } + } + + // We deliver no specific Neo4j transaction output beyond what goes to the context + // output + // + return null; + }; + + if (logCypher) { + String parametersString = getParametersString(parametersMap); + + String readWrite = writeTransaction ? "write" : "read"; + LOG.info( + "Starting a " + + readWrite + + " transaction for cypher: " + + cypher + + ", parameters: " + + parametersString); + } + + // There are 2 ways to do a transaction on Neo4j: read or write + // It's important that the right type is selected, especially in clustered configurations. + // + if (driverSession.session == null) { + throw new RuntimeException("neo4j session was not initialized correctly"); + } else { + if (writeTransaction) { + driverSession.session.writeTransaction(transactionWork, transactionConfig); + } else { + driverSession.session.readTransaction(transactionWork, transactionConfig); + } + } + } + } + + /** + * Wraps a {@link DriverConfiguration} to provide a {@link Driver}. + * + * <p>At most a single {@link Driver} instance will be constructed during pipeline execution for + * each unique {@link DriverConfiguration} within the pipeline. + */ + public static class DriverProviderFromDriverConfiguration + implements SerializableFunction<Void, Driver>, HasDisplayData { + private final DriverConfiguration config; + + private DriverProviderFromDriverConfiguration(DriverConfiguration config) { + this.config = config; + } + + public static SerializableFunction<Void, Driver> of(DriverConfiguration config) { + return new DriverProviderFromDriverConfiguration(config); + } + + @Override + public Driver apply(Void input) { + return config.buildDriver(); + } + + @Override + public void populateDisplayData(DisplayData.Builder builder) { + config.populateDisplayData(builder); + } + } + + /** This is the class which handles the work behind the {@link #writeUnwind()} method. */ + @AutoValue + public abstract static class WriteUnwind<ParameterT> + extends PTransform<PCollection<ParameterT>, PDone> { + + abstract @Nullable SerializableFunction<Void, Driver> getDriverProviderFn(); + + abstract @Nullable ValueProvider<SessionConfig> getSessionConfig(); + + abstract @Nullable ValueProvider<String> getCypher(); + + abstract @Nullable ValueProvider<String> getUnwindMapName(); + + abstract @Nullable ValueProvider<TransactionConfig> getTransactionConfig(); + + abstract @Nullable SerializableFunction<ParameterT, Map<String, Object>> + getParametersFunction(); + + abstract @Nullable ValueProvider<Long> getBatchSize(); + + abstract @Nullable ValueProvider<Boolean> getLogCypher(); + + abstract Builder<ParameterT> toBuilder(); + + public WriteUnwind<ParameterT> withDriverConfiguration(DriverConfiguration config) { + return toBuilder() + .setDriverProviderFn(new DriverProviderFromDriverConfiguration(config)) + .build(); + } + + public WriteUnwind<ParameterT> withCypher(String cypher) { + checkArgument( + cypher != null, "Neo4jIO.writeUnwind().withCypher(query) called with null cypher query"); + return withCypher(ValueProvider.StaticValueProvider.of(cypher)); + } + + public WriteUnwind<ParameterT> withCypher(ValueProvider<String> cypher) { + checkArgument( + cypher != null, "Neo4jIO.writeUnwind().withCypher(cypher) called with null cypher"); + return toBuilder().setCypher(cypher).build(); + } + + public WriteUnwind<ParameterT> withUnwindMapName(String mapName) { + checkArgument( + mapName != null, + "Neo4jIO.writeUnwind().withUnwindMapName(query) called with null mapName"); + return withUnwindMapName(ValueProvider.StaticValueProvider.of(mapName)); + } + + public WriteUnwind<ParameterT> withUnwindMapName(ValueProvider<String> mapName) { + checkArgument( + mapName != null, + "Neo4jIO.writeUnwind().withUnwindMapName(cypher) called with null mapName"); + return toBuilder().setUnwindMapName(mapName).build(); + } + + public WriteUnwind<ParameterT> withTransactionConfig(TransactionConfig transactionConfig) { + checkArgument( + transactionConfig != null, + "Neo4jIO.writeUnwind().withTransactionConfig(config) called with null transactionConfig"); + return withTransactionConfig(ValueProvider.StaticValueProvider.of(transactionConfig)); + } + + public WriteUnwind<ParameterT> withTransactionConfig( + ValueProvider<TransactionConfig> transactionConfig) { + checkArgument( + transactionConfig != null, + "Neo4jIO.writeUnwind().withTransactionConfig(config) called with null transactionConfig"); + return toBuilder().setTransactionConfig(transactionConfig).build(); + } + + public WriteUnwind<ParameterT> withSessionConfig(SessionConfig sessionConfig) { + checkArgument( + sessionConfig != null, + "Neo4jIO.writeUnwind().withSessionConfig(sessionConfig) called with null sessionConfig"); + return withSessionConfig(ValueProvider.StaticValueProvider.of(sessionConfig)); + } + + public WriteUnwind<ParameterT> withSessionConfig(ValueProvider<SessionConfig> sessionConfig) { + checkArgument( + sessionConfig != null, + "Neo4jIO.writeUnwind().withSessionConfig(sessionConfig) called with null sessionConfig"); + return toBuilder().setSessionConfig(sessionConfig).build(); + } + + // Batch size + public WriteUnwind<ParameterT> withBatchSize(long batchSize) { + checkArgument( + batchSize > 0, "Neo4jIO.writeUnwind().withFetchSize(query) called with batchSize<=0"); + return withBatchSize(ValueProvider.StaticValueProvider.of(batchSize)); + } + + public WriteUnwind<ParameterT> withBatchSize(ValueProvider<Long> batchSize) { + checkArgument( + batchSize != null && batchSize.get() >= 0, + "Neo4jIO.readAll().withBatchSize(query) called with batchSize<=0"); + return toBuilder().setBatchSize(batchSize).build(); + } + + public WriteUnwind<ParameterT> withParametersFunction( + SerializableFunction<ParameterT, Map<String, Object>> parametersFunction) { + checkArgument( + parametersFunction != null, + "Neo4jIO.readAll().withParametersFunction(parametersFunction) called with null parametersFunction"); + return toBuilder().setParametersFunction(parametersFunction).build(); + } + + public WriteUnwind<ParameterT> withCypherLogging() { + return toBuilder().setLogCypher(ValueProvider.StaticValueProvider.of(Boolean.TRUE)).build(); + } + + @Override + public PDone expand(PCollection<ParameterT> input) { + + final SerializableFunction<Void, Driver> driverProviderFn = getDriverProviderFn(); + final SerializableFunction<ParameterT, Map<String, Object>> parametersFunction = + getParametersFunction(); + SessionConfig sessionConfig = getProvidedValue(getSessionConfig()); + if (sessionConfig == null) { + sessionConfig = SessionConfig.defaultConfig(); + } + TransactionConfig transactionConfig = getProvidedValue(getTransactionConfig()); + if (transactionConfig == null) { + transactionConfig = TransactionConfig.empty(); + } + final String cypher = getProvidedValue(getCypher()); + checkArgument(cypher != null, "please provide an unwind cypher statement to execute"); + final String unwindMapName = getProvidedValue(getUnwindMapName()); + checkArgument(unwindMapName != null, "please provide an unwind map name"); + + Long batchSize = getProvidedValue(getBatchSize()); + if (batchSize == null || batchSize <= 0) { + batchSize = 5000L; + } + + Boolean logCypher = getProvidedValue(getLogCypher()); + if (logCypher == null) { + logCypher = Boolean.FALSE; + } + + if (driverProviderFn == null) { + throw new RuntimeException("please provide a driver provider"); + } + if (parametersFunction == null) { + throw new RuntimeException("please provide a parameters function"); + } + WriteUnwindFn<ParameterT> writeFn = + new WriteUnwindFn<>( + driverProviderFn, + sessionConfig, + transactionConfig, + cypher, + parametersFunction, + batchSize, + logCypher, + unwindMapName); + + input.apply(ParDo.of(writeFn)); + + return PDone.in(input.getPipeline()); + } + + @Override + public void populateDisplayData(DisplayData.Builder builder) { + super.populateDisplayData(builder); + builder.add(DisplayData.item("cypher", getCypher())); + + final SerializableFunction<Void, Driver> driverProviderFn = getDriverProviderFn(); + if (driverProviderFn != null) { + if (driverProviderFn instanceof HasDisplayData) { + ((HasDisplayData) driverProviderFn).populateDisplayData(builder); + } + } + } + + @AutoValue.Builder + abstract static class Builder<ParameterT> { + abstract Builder<ParameterT> setDriverProviderFn( + SerializableFunction<Void, Driver> driverProviderFn); + + abstract Builder<ParameterT> setSessionConfig(ValueProvider<SessionConfig> sessionConfig); + + abstract Builder<ParameterT> setTransactionConfig( + ValueProvider<TransactionConfig> transactionConfig); + + abstract Builder<ParameterT> setCypher(ValueProvider<String> cypher); + + abstract Builder<ParameterT> setUnwindMapName(ValueProvider<String> unwindMapName); + + abstract Builder<ParameterT> setParametersFunction( + SerializableFunction<ParameterT, Map<String, Object>> parametersFunction); + + abstract Builder<ParameterT> setBatchSize(ValueProvider<Long> batchSize); + + abstract Builder<ParameterT> setLogCypher(ValueProvider<Boolean> logCypher); + + abstract WriteUnwind<ParameterT> build(); + } + } + + /** A {@link DoFn} to execute a Cypher query to read from Neo4j. */ + private static class WriteUnwindFn<ParameterT> extends ReadWriteFn<ParameterT, Void> { + + private final @NonNull String cypher; + private final @Nullable SerializableFunction<ParameterT, Map<String, Object>> + parametersFunction; + private final boolean logCypher; + private final long batchSize; + private final @NonNull String unwindMapName; + + private long elementsInput; + private boolean loggingDone; + private List<Map<String, Object>> unwindList; + + private WriteUnwindFn( + @NonNull SerializableFunction<Void, Driver> driverProviderFn, + @NonNull SessionConfig sessionConfig, + @NonNull TransactionConfig transactionConfig, + @NonNull String cypher, + @Nullable SerializableFunction<ParameterT, Map<String, Object>> parametersFunction, + long batchSize, + boolean logCypher, + String unwindMapName) { + super(driverProviderFn, sessionConfig, transactionConfig); + this.cypher = cypher; + this.parametersFunction = parametersFunction; + this.logCypher = logCypher; + this.batchSize = batchSize; + this.unwindMapName = unwindMapName; + + unwindList = new ArrayList<>(); + + elementsInput = 0; + loggingDone = false; + } + + @ProcessElement + public void processElement(ProcessContext context) { + // Map the input data to the parameters map... + // + ParameterT parameters = context.element(); + if (parametersFunction != null) { + // Every input element creates a new Map<String,Object> entry in unwindList + // + unwindList.add(parametersFunction.apply(parameters)); + } else { + // Someone is writing a bunch of static or procedurally generated values to Neo4j + unwindList.add(Collections.emptyMap()); + } + elementsInput++; + + if (elementsInput >= batchSize) { + // Execute the cypher query with the collected parameters map + // + executeCypherUnwindStatement(); + } + } + + private void executeCypherUnwindStatement() { + // In case of errors and no actual input read (error in mapper) we don't have input + // So we don't want to execute any cypher in this case. There's no need to generate even more + // errors + // + if (elementsInput == 0) { + return; + } + + // Add the accumulated list to the overall parameters map + // It contains a single parameter to unwind + // + final Map<String, Object> parametersMap = new HashMap<>(); + parametersMap.put(unwindMapName, unwindList); + + // Every "write" transaction writes a batch of elements to Neo4j. + // The changes to the database are automatically committed. + // + TransactionWork<Void> transactionWork = + transaction -> { + Result result = transaction.run(cypher, parametersMap); + while (result.hasNext()) { + // This just consumes any output but the function basically has no output + // To be revisited based on requirements. + // + result.next(); + } + return null; + }; + + if (logCypher && !loggingDone) { + String parametersString = getParametersString(parametersMap); + LOG.info( + "Starting a write transaction for unwind statement cypher: " + + cypher + + ", parameters: " + + parametersString); + loggingDone = true; + } + + if (driverSession.session == null) { + throw new RuntimeException("neo4j session was not initialized correctly"); Review comment: s / which should should be correct could be limited / which should be correct but could be limited -- This is an automated message from the Apache Git Service. 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