GH-685 - Introduce spring.modulith.events.jdbc.schema to allow defining the database schema for the event_publication table.

Author: raedbh

spring-modulith-events/spring-modulith-events-jdbc/src/main/java/org/springframework/modulith/events/jdbc/DatabaseSchemaInitializer.java

@@ -15,13 +15,78 @@
  */
 package org.springframework.modulith.events.jdbc;
 
+import java.sql.Connection;
+
+import javax.sql.DataSource;
+
 import org.springframework.beans.factory.InitializingBean;
+import org.springframework.core.io.ResourceLoader;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.jdbc.datasource.init.ResourceDatabasePopulator;
+import org.springframework.util.ObjectUtils;
 
 /**
  * Initializes the DB schema used to store events
  *
  * @author Dmitry Belyaev
  * @author Björn Kieling
  * @author Oliver Drotbohm
+ * @author Raed Ben Hamouda
  */
-interface DatabaseSchemaInitializer extends InitializingBean {}
+class DatabaseSchemaInitializer implements InitializingBean {
+
+	private final DataSource dataSource;
+	private final ResourceLoader resourceLoader;
+	private final DatabaseType databaseType;
+	private final JdbcTemplate jdbcTemplate;
+	private final JdbcConfigurationProperties properties;
+
+	DatabaseSchemaInitializer(DataSource dataSource, ResourceLoader resourceLoader, DatabaseType databaseType,
+			JdbcTemplate jdbcTemplate, JdbcConfigurationProperties properties) {
+
+		this.dataSource = dataSource;
+		this.resourceLoader = resourceLoader;
+		this.databaseType = databaseType;
+		this.jdbcTemplate = jdbcTemplate;
+		this.properties = properties;
+	}
+
+	@Override
+	public void afterPropertiesSet() throws Exception {
+
+		String initialSchema;
+		try (Connection connection = dataSource.getConnection()) {
+
+			initialSchema = connection.getSchema();
+
+			String schemaName = properties.getSchema();
+			if (!ObjectUtils.isEmpty(schemaName)) { // A schema name has been specified.
+
+				if (eventPublicationTableExists(jdbcTemplate, schemaName)) {
+					return;
+				}
+
+				jdbcTemplate.execute("CREATE SCHEMA IF NOT EXISTS " + schemaName);
+				jdbcTemplate.execute(databaseType.sqlStatementSetSchema(schemaName));
+			}
+
+			var locator = new DatabaseSchemaLocator(resourceLoader);
+			new ResourceDatabasePopulator(locator.getSchemaResource(databaseType)).execute(dataSource);
+
+			// Return to the initial schema.
+			if (initialSchema != null) {
+				jdbcTemplate.execute(databaseType.sqlStatementSetSchema(initialSchema));
+			}
+		}
+	}
+
+	private boolean eventPublicationTableExists(JdbcTemplate jdbcTemplate, String schema) {
+		String query = """
+				SELECT COUNT(*)
+				FROM information_schema.tables
+				WHERE table_schema = ? AND table_name = 'EVENT_PUBLICATION'
+				""";
+		Integer count = jdbcTemplate.queryForObject(query, Integer.class, schema);
+		return count != null && count > 0;
+	}
+}

spring-modulith-events/spring-modulith-events-jdbc/src/main/java/org/springframework/modulith/events/jdbc/DatabaseType.java

@@ -24,6 +24,7 @@
  * @author Dmitry Belyaev
  * @author Björn Kieling
  * @author Oliver Drotbohm
+ * @author Raed Ben Hamouda
  */
 enum DatabaseType {
 
@@ -75,4 +76,11 @@ UUID databaseToUUID(Object id) {
 	String getSchemaResourceFilename() {
 		return "/schema-" + value + ".sql";
 	}
+
+	String sqlStatementSetSchema(String schema) {
+		return switch (this) {
+			case MYSQL, H2, HSQLDB -> "SET SCHEMA " + schema;
+			case POSTGRES -> "SET search_path TO " + schema;
+		};
+	}
 }

spring-modulith-events/spring-modulith-events-jdbc/src/main/java/org/springframework/modulith/events/jdbc/JdbcConfigurationProperties.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2022-2024 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.modulith.events.jdbc;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.boot.context.properties.bind.ConstructorBinding;
+import org.springframework.boot.context.properties.bind.DefaultValue;
+import org.springframework.lang.Nullable;
+
+/**
+ * Configuration properties for JDBC.
+ *
+ * @author Raed Ben Hamouda
+ */
+@ConfigurationProperties(prefix = "spring.modulith.events.jdbc")
+class JdbcConfigurationProperties {
+
+	private final boolean schemaInitializationEnabled;
+	private final String schema;
+
+	/**
+	 * Creates a new {@link JdbcConfigurationProperties} instance.
+	 *
+	 * @param schemaInitializationEnabled whether to initialize the JDBC event publication schema. Defaults to {@literal false}.
+	 * @param schema the schema name of event publication table, can be {@literal null}.
+	 */
+	@ConstructorBinding
+	JdbcConfigurationProperties(@DefaultValue("false") boolean schemaInitializationEnabled, @Nullable String schema) {
+
+		this.schemaInitializationEnabled = schemaInitializationEnabled;
+		this.schema = schema;
+	}
+
+	/**
+	 * Whether to initialize the JDBC event publication schema.
+	 */
+	public boolean isSchemaInitializationEnabled() {
+		return schemaInitializationEnabled;
+	}
+
+	/**
+	 * The name of the schema where the event publication table resides.
+	 *
+	 * @return can be {@literal null}.
+	 */
+	public String getSchema() {
+		return schema;
+	}
+}

spring-modulith-events/spring-modulith-events-jdbc/src/main/java/org/springframework/modulith/events/jdbc/JdbcEventPublicationAutoConfiguration.java

@@ -21,11 +21,11 @@
 
 import org.springframework.boot.autoconfigure.AutoConfigureBefore;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.jdbc.core.JdbcTemplate;
-import org.springframework.jdbc.datasource.init.ResourceDatabasePopulator;
 import org.springframework.jdbc.support.JdbcUtils;
 import org.springframework.modulith.events.config.EventPublicationAutoConfiguration;
 import org.springframework.modulith.events.config.EventPublicationConfigurationExtension;
@@ -35,9 +35,11 @@
  * @author Dmitry Belyaev
  * @author Björn Kieling
  * @author Oliver Drotbohm
+ * @author Raed Ben Hamouda
  */
 @Configuration(proxyBeanMethods = false)
 @AutoConfigureBefore(EventPublicationAutoConfiguration.class)
+@EnableConfigurationProperties(JdbcConfigurationProperties.class)
 class JdbcEventPublicationAutoConfiguration implements EventPublicationConfigurationExtension {
 
 	@Bean
@@ -47,22 +49,17 @@ DatabaseType databaseType(DataSource dataSource) {
 
 	@Bean
 	JdbcEventPublicationRepository jdbcEventPublicationRepository(JdbcTemplate jdbcTemplate,
-			EventSerializer serializer, DatabaseType databaseType) {
+			EventSerializer serializer, DatabaseType databaseType, JdbcConfigurationProperties properties) {
 
-		return new JdbcEventPublicationRepository(jdbcTemplate, serializer, databaseType);
+		return new JdbcEventPublicationRepository(jdbcTemplate, serializer, databaseType, properties);
 	}
 
 	@Bean
 	@ConditionalOnProperty(name = "spring.modulith.events.jdbc.schema-initialization.enabled", havingValue = "true")
 	DatabaseSchemaInitializer databaseSchemaInitializer(DataSource dataSource, ResourceLoader resourceLoader,
-			DatabaseType databaseType) {
+			DatabaseType databaseType, JdbcTemplate jdbcTemplate, JdbcConfigurationProperties properties) {
 
-		return () -> {
-
-			var locator = new DatabaseSchemaLocator(resourceLoader);
-
-			new ResourceDatabasePopulator(locator.getSchemaResource(databaseType)).execute(dataSource);
-		};
+		return new DatabaseSchemaInitializer(dataSource, resourceLoader, databaseType, jdbcTemplate, properties);
 	}
 
 	private static String fromDataSource(DataSource dataSource) {