#141 - Add support for schema initialization.

We now provide DatabasePopulator and ScriptUtils to run SQL scripts using R2DBC Connections to initialize and clean up databases.

Author: mp911de

src/main/java/org/springframework/data/r2dbc/connectionfactory/R2dbcTransactionManager.java

@@ -421,7 +421,7 @@ protected Mono<Void> doCleanupAfterCompletion(TransactionSynchronizationManager
 	 * Prepare the transactional {@link Connection} right after transaction begin.
 	 * <p>
 	 * The default implementation executes a "SET TRANSACTION READ ONLY" statement if the {@link #setEnforceReadOnly
-	 * "enforceReadOnly"} flag is set to {@code true} and the transaction definition indicates a read-only transaction.
+	 * "enforceReadOnly"} flag is set to {@literal true} and the transaction definition indicates a read-only transaction.
 	 * <p>
 	 * The "SET TRANSACTION READ ONLY" is understood by Oracle, MySQL and Postgres and may work with other databases as
 	 * well. If you'd like to adapt this treatment, override this method accordingly.

src/main/java/org/springframework/data/r2dbc/connectionfactory/init/CannotReadScriptException.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed 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
+ *
+ *      https://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.springframework.data.r2dbc.connectionfactory.init;
+
+import org.springframework.core.io.support.EncodedResource;
+
+/**
+ * Thrown by {@link ScriptUtils} if an SQL script cannot be read.
+ *
+ * @author Mark Paluch
+ */
+public class CannotReadScriptException extends ScriptException {
+
+	private static final long serialVersionUID = 7253084944991764250L;
+
+	/**
+	 * Creates a new {@link CannotReadScriptException}.
+	 *
+	 * @param resource the resource that cannot be read from.
+	 * @param cause the underlying cause of the resource access failure.
+	 */
+	public CannotReadScriptException(EncodedResource resource, Throwable cause) {
+		super("Cannot read SQL script from " + resource, cause);
+	}
+}

src/main/java/org/springframework/data/r2dbc/connectionfactory/init/CompositeDatabasePopulator.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed 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
+ *
+ *      https://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.springframework.data.r2dbc.connectionfactory.init;
+
+import io.r2dbc.spi.Connection;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+
+import org.springframework.util.Assert;
+
+/**
+ * Composite {@link DatabasePopulator} that delegates to a list of given {@link DatabasePopulator} implementations,
+ * executing all scripts.
+ *
+ * @author Mark Paluch
+ */
+public class CompositeDatabasePopulator implements DatabasePopulator {
+
+	private final List<DatabasePopulator> populators = new ArrayList<>(4);
+
+	/**
+	 * Creates an empty {@link CompositeDatabasePopulator}.
+	 *
+	 * @see #setPopulators
+	 * @see #addPopulators
+	 */
+	public CompositeDatabasePopulator() {}
+
+	/**
+	 * Creates a {@link CompositeDatabasePopulator}. with the given populators.
+	 *
+	 * @param populators one or more populators to delegate to.
+	 */
+	public CompositeDatabasePopulator(Collection<DatabasePopulator> populators) {
+
+		Assert.notNull(populators, "Collection of DatabasePopulator must not be null!");
+
+		this.populators.addAll(populators);
+	}
+
+	/**
+	 * Creates a {@link CompositeDatabasePopulator} with the given populators.
+	 *
+	 * @param populators one or more populators to delegate to.
+	 */
+	public CompositeDatabasePopulator(DatabasePopulator... populators) {
+
+		Assert.notNull(populators, "DatabasePopulators must not be null!");
+
+		this.populators.addAll(Arrays.asList(populators));
+	}
+
+	/**
+	 * Specify one or more populators to delegate to.
+	 */
+	public void setPopulators(DatabasePopulator... populators) {
+
+		Assert.notNull(populators, "DatabasePopulators must not be null!");
+
+		this.populators.clear();
+		this.populators.addAll(Arrays.asList(populators));
+	}
+
+	/**
+	 * Add one or more populators to the list of delegates.
+	 */
+	public void addPopulators(DatabasePopulator... populators) {
+
+		Assert.notNull(populators, "DatabasePopulators must not be null!");
+
+		this.populators.addAll(Arrays.asList(populators));
+	}
+
+	@Override
+	public Mono<Void> populate(Connection connection) throws ScriptException {
+
+		Assert.notNull(connection, "Connection must not be null!");
+
+		return Flux.fromIterable(this.populators).concatMap(it -> it.populate(connection)).then();
+	}
+}

src/main/java/org/springframework/data/r2dbc/connectionfactory/init/ConnectionFactoryInitializer.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed 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
+ *
+ *      https://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.springframework.data.r2dbc.connectionfactory.init;
+
+import io.r2dbc.spi.ConnectionFactory;
+
+import org.springframework.beans.factory.DisposableBean;
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+
+/**
+ * Used to {@link #setDatabasePopulator set up} a database during initialization and {@link #setDatabaseCleaner clean
+ * up} a database during destruction.
+ *
+ * @author Mark Paluch
+ * @see DatabasePopulator
+ */
+public class ConnectionFactoryInitializer implements InitializingBean, DisposableBean {
+
+	private @Nullable ConnectionFactory connectionFactory;
+
+	private @Nullable DatabasePopulator databasePopulator;
+
+	private @Nullable DatabasePopulator databaseCleaner;
+
+	private boolean enabled = true;
+
+	/**
+	 * The {@link ConnectionFactory} for the database to populate when this component is initialized and to clean up when
+	 * this component is shut down.
+	 * <p/>
+	 * This property is mandatory with no default provided.
+	 *
+	 * @param connectionFactory the R2DBC {@link ConnectionFactory}.
+	 */
+	public void setConnectionFactory(ConnectionFactory connectionFactory) {
+		this.connectionFactory = connectionFactory;
+	}
+
+	/**
+	 * Set the {@link DatabasePopulator} to execute during the bean initialization phase.
+	 *
+	 * @param databasePopulator the {@link DatabasePopulator} to use during initialization
+	 * @see #setDatabaseCleaner
+	 */
+	public void setDatabasePopulator(DatabasePopulator databasePopulator) {
+		this.databasePopulator = databasePopulator;
+	}
+
+	/**
+	 * Set the {@link DatabasePopulator} to execute during the bean destruction phase, cleaning up the database and
+	 * leaving it in a known state for others.
+	 *
+	 * @param databaseCleaner the {@link DatabasePopulator} to use during destruction
+	 * @see #setDatabasePopulator
+	 */
+	public void setDatabaseCleaner(DatabasePopulator databaseCleaner) {
+		this.databaseCleaner = databaseCleaner;
+	}
+
+	/**
+	 * Flag to explicitly enable or disable the {@link #setDatabasePopulator database populator} and
+	 * {@link #setDatabaseCleaner database cleaner}.
+	 *
+	 * @param enabled {@literal true} if the database populator and database cleaner should be called on startup and
+	 *          shutdown, respectively
+	 */
+	public void setEnabled(boolean enabled) {
+		this.enabled = enabled;
+	}
+
+	/**
+	 * Use the {@link #setDatabasePopulator database populator} to set up the database.
+	 */
+	@Override
+	public void afterPropertiesSet() {
+		execute(this.databasePopulator);
+	}
+
+	/**
+	 * Use the {@link #setDatabaseCleaner database cleaner} to clean up the database.
+	 */
+	@Override
+	public void destroy() {
+		execute(this.databaseCleaner);
+	}
+
+	private void execute(@Nullable DatabasePopulator populator) {
+
+		Assert.state(this.connectionFactory != null, "ConnectionFactory must be set");
+
+		if (this.enabled && populator != null) {
+			DatabasePopulatorUtils.execute(populator, this.connectionFactory);
+		}
+	}
+}

src/main/java/org/springframework/data/r2dbc/connectionfactory/init/DatabasePopulator.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed 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
+ *
+ *      https://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.springframework.data.r2dbc.connectionfactory.init;
+
+import io.r2dbc.spi.Connection;
+import reactor.core.publisher.Mono;
+
+/**
+ * Strategy used to populate, initialize, or clean up a database.
+ *
+ * @author Mark Paluch
+ * @see ResourceDatabasePopulator
+ * @see DatabasePopulatorUtils
+ * @see ConnectionFactoryInitializer
+ */
+@FunctionalInterface
+public interface DatabasePopulator {
+
+	/**
+	 * Populate, initialize, or clean up the database using the provided R2DBC {@link Connection}.
+	 *
+	 * @param connection the R2DBC connection to use to populate the db; already configured and ready to use, must not be
+	 *          {@literal null}.
+	 * @return {@link Mono} that initiates script execution and is notified upon completion.
+	 * @throws ScriptException in all other error cases
+	 * @see DatabasePopulatorUtils#execute
+	 */
+	Mono<Void> populate(Connection connection) throws ScriptException;
+}

src/main/java/org/springframework/data/r2dbc/connectionfactory/init/DatabasePopulatorUtils.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed 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
+ *
+ *      https://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.springframework.data.r2dbc.connectionfactory.init;
+
+import io.r2dbc.spi.Connection;
+import io.r2dbc.spi.ConnectionFactory;
+import reactor.core.publisher.Mono;
+import reactor.util.function.Tuple2;
+
+import org.springframework.dao.DataAccessException;
+import org.springframework.data.r2dbc.connectionfactory.ConnectionFactoryUtils;
+import org.springframework.util.Assert;
+
+/**
+ * Utility methods for executing a {@link DatabasePopulator}.
+ *
+ * @author Mark Paluch
+ */
+public abstract class DatabasePopulatorUtils {
+
+	// utility constructor
+	private DatabasePopulatorUtils() {}
+
+	/**
+	 * Execute the given {@link DatabasePopulator} against the given {@link io.r2dbc.spi.ConnectionFactory}.
+	 *
+	 * @param populator the {@link DatabasePopulator} to execute.
+	 * @param connectionFactory the {@link ConnectionFactory} to execute against.
+	 * @return {@link Mono} that initiates {@link DatabasePopulator#populate(Connection)} and is notified upon completion.
+	 */
+	public static Mono<Void> execute(DatabasePopulator populator, ConnectionFactory connectionFactory)
+			throws DataAccessException {
+
+		Assert.notNull(populator, "DatabasePopulator must not be null");
+		Assert.notNull(connectionFactory, "ConnectionFactory must not be null");
+
+		return Mono.usingWhen(ConnectionFactoryUtils.getConnection(connectionFactory).map(Tuple2::getT1), //
+				populator::populate, //
+				it -> ConnectionFactoryUtils.releaseConnection(it, connectionFactory), //
+				it -> ConnectionFactoryUtils.releaseConnection(it, connectionFactory))
+				.onErrorMap(ex -> !(ex instanceof ScriptException), ex -> {
+					return new UncategorizedScriptException("Failed to execute database script", ex);
+				});
+	}
+}