Introduce EnvironmentPostProcessor for R2DBC support in Cloud Sql

spring-cloud-gcp-autoconfigure/pom.xml

@@ -117,6 +117,31 @@
             <scope>test</scope>
         </dependency>
 
+        <!--R2DBC : mySQL connector factory -->
+        <dependency>
+            <groupId>com.google.cloud.sql</groupId>
+            <artifactId>cloud-sql-connector-r2dbc-mysql</artifactId>
+            <optional>true</optional>
+        </dependency>
+        <dependency>
+            <groupId>dev.miku</groupId>
+            <artifactId>r2dbc-mysql</artifactId>
+            <optional>true</optional>
+        </dependency>
+
+
+        <!--R2DBC : PostgreSQL connector factory -->
+        <dependency>
+            <groupId>com.google.cloud.sql</groupId>
+            <artifactId>cloud-sql-connector-r2dbc-postgres</artifactId>
+            <optional>true</optional>
+        </dependency>
+        <dependency>
+            <groupId>io.r2dbc</groupId>
+            <artifactId>r2dbc-postgresql</artifactId>
+            <optional>true</optional>
+        </dependency>
+
         <!-- Storage -->
         <dependency>
             <groupId>com.google.cloud</groupId>

spring-cloud-gcp-autoconfigure/src/main/java/com/google/cloud/spring/autoconfigure/sql/CloudSqlEnvironmentPostProcessor.java

@@ -29,14 +29,8 @@
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.boot.SpringApplication;
-import org.springframework.boot.context.properties.ConfigurationProperties;
-import org.springframework.boot.context.properties.bind.Binder;
-import org.springframework.boot.context.properties.bind.PlaceholdersResolver;
-import org.springframework.boot.context.properties.bind.PropertySourcesPlaceholdersResolver;
-import org.springframework.boot.context.properties.source.ConfigurationPropertySources;
 import org.springframework.boot.env.EnvironmentPostProcessor;
 import org.springframework.core.env.ConfigurableEnvironment;
-import org.springframework.core.env.Environment;
 import org.springframework.core.env.MapPropertySource;
 import org.springframework.core.io.Resource;
 import org.springframework.util.ClassUtils;
@@ -70,19 +64,8 @@ public void postProcessEnvironment(ConfigurableEnvironment environment, SpringAp
 				LOGGER.info("post-processing Cloud SQL properties for + " + databaseType.name());
 			}
 
-			// Bind properties without resolving Secret Manager placeholders
-			Binder binder = new Binder(ConfigurationPropertySources.get(environment),
-					new NonSecretsManagerPropertiesPlaceholdersResolver(environment),
-					null, null, null);
-
-			String cloudSqlPropertiesPrefix = GcpCloudSqlProperties.class.getAnnotation(ConfigurationProperties.class).value();
-			GcpCloudSqlProperties sqlProperties = binder
-					.bind(cloudSqlPropertiesPrefix, GcpCloudSqlProperties.class)
-					.orElse(new GcpCloudSqlProperties());
-			GcpProperties gcpProperties = binder
-					.bind(cloudSqlPropertiesPrefix, GcpProperties.class)
-					.orElse(new GcpProperties());
-
+			PropertiesRetriever propertiesRetriever = new PropertiesRetriever(environment);
+			GcpCloudSqlProperties sqlProperties = propertiesRetriever.getCloudSqlProperties();
 			CloudSqlJdbcInfoProvider cloudSqlJdbcInfoProvider = new DefaultCloudSqlJdbcInfoProvider(sqlProperties, databaseType);
 			if (LOGGER.isInfoEnabled()) {
 				LOGGER.info("Default " + databaseType.name()
@@ -104,7 +87,7 @@ public void postProcessEnvironment(ConfigurableEnvironment environment, SpringAp
 			environment.getPropertySources()
 					.addFirst(new MapPropertySource("CLOUD_SQL_DATA_SOURCE_URL", primaryMap));
 
-			setCredentials(sqlProperties, gcpProperties);
+			setCredentials(sqlProperties, propertiesRetriever.getGcpProperties());
 
 			// support usage metrics
 			CoreSocketFactory.setApplicationName("spring-cloud-gcp-sql/"
@@ -193,22 +176,4 @@ private void setCredentialsFileProperty(Resource credentialsLocation) {
 			LOGGER.info("Error reading Cloud SQL credentials file.", ioe);
 		}
 	}
-
-	private static class NonSecretsManagerPropertiesPlaceholdersResolver implements PlaceholdersResolver {
-		private PlaceholdersResolver resolver;
-
-		NonSecretsManagerPropertiesPlaceholdersResolver(Environment environment) {
-			this.resolver = new PropertySourcesPlaceholdersResolver(environment);
-		}
-
-		@Override
-		public Object resolvePlaceholders(Object value) {
-			if (value.toString().contains("sm://")) {
-				return value;
-			}
-			else {
-				return resolver.resolvePlaceholders(value);
-			}
-		}
-	}
 }

spring-cloud-gcp-autoconfigure/src/main/java/com/google/cloud/spring/autoconfigure/sql/DatabaseType.java

@@ -29,24 +29,37 @@ public enum DatabaseType {
 	 */
 	MYSQL("com.mysql.cj.jdbc.Driver", "jdbc:mysql://google/%s?"
 			+ "socketFactory=com.google.cloud.sql.mysql.SocketFactory"
-			+ "&cloudSqlInstance=%s", "root"),
+			+ "&cloudSqlInstance=%s", null, "root"),
 
 	/**
 	 * Postgresql constants.
 	 */
 	POSTGRESQL("org.postgresql.Driver", "jdbc:postgresql://google/%s?"
 			+ "socketFactory=com.google.cloud.sql.postgres.SocketFactory"
-			+ "&cloudSqlInstance=%s", "postgres");
+			+ "&cloudSqlInstance=%s", null, "postgres"),
+
+	/**
+	 * R2DBC MySQL constants.
+	 */
+	R2DBC_MYSQL(null, null, "r2dbc:gcp:mysql://%s/%s", "root"),
+
+	/**
+	 * R2DBC Postgresql constants.
+	 */
+	R2DBC_POSTGRESQL(null, null, "r2dbc:gcp:postgres://%s/%s", "postgres");
 
 	private final String jdbcDriverName;
 
 	private final String jdbcUrlTemplate;
 
+	private final String r2dbcUrlTemplate;
+
 	private final String defaultUsername;
 
-	DatabaseType(String jdbcDriverName, String jdbcUrlTemplate, String defaultUsername) {
+	DatabaseType(String jdbcDriverName, String jdbcUrlTemplate, String r2dbcUrlTemplate, String defaultUsername) {
 		this.jdbcDriverName = jdbcDriverName;
 		this.jdbcUrlTemplate = jdbcUrlTemplate;
+		this.r2dbcUrlTemplate = r2dbcUrlTemplate;
 		this.defaultUsername = defaultUsername;
 	}
 
@@ -58,6 +71,10 @@ public String getJdbcUrlTemplate() {
 		return this.jdbcUrlTemplate;
 	}
 
+	public String getR2dbcUrlTemplate() {
+		return this.r2dbcUrlTemplate;
+	}
+
 	public String getDefaultUsername() {
 		return defaultUsername;
 	}

spring-cloud-gcp-autoconfigure/src/main/java/com/google/cloud/spring/autoconfigure/sql/PropertiesRetriever.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2021-2022 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 com.google.cloud.spring.autoconfigure.sql;
+
+import com.google.cloud.spring.autoconfigure.core.GcpProperties;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.boot.context.properties.bind.Binder;
+import org.springframework.boot.context.properties.bind.PlaceholdersResolver;
+import org.springframework.boot.context.properties.bind.PropertySourcesPlaceholdersResolver;
+import org.springframework.boot.context.properties.source.ConfigurationPropertySources;
+import org.springframework.core.env.Environment;
+
+/**
+ * Helper class to derive Cloud SQL and GCP properties from the user configuration
+ * (application.properties, for example).
+ */
+class PropertiesRetriever {
+
+	private Binder binder;
+
+	PropertiesRetriever(Environment environment) {
+		// Bind properties without resolving Secret Manager placeholders
+		this.binder = new Binder(ConfigurationPropertySources.get(environment),
+				new NonSecretsManagerPropertiesPlaceholdersResolver(environment),
+				null, null, null);
+	}
+
+	GcpCloudSqlProperties getCloudSqlProperties() {
+		String cloudSqlPropertiesPrefix = GcpCloudSqlProperties.class.getAnnotation(ConfigurationProperties.class)
+				.value();
+		return this.binder
+				.bind(cloudSqlPropertiesPrefix, GcpCloudSqlProperties.class)
+				.orElse(new GcpCloudSqlProperties());
+	}
+
+	GcpProperties getGcpProperties() {
+		String gcpPropertiesPrefix = GcpProperties.class.getAnnotation(ConfigurationProperties.class).value();
+		return this.binder
+				.bind(gcpPropertiesPrefix, GcpProperties.class)
+				.orElse(new GcpProperties());
+	}
+
+	private static class NonSecretsManagerPropertiesPlaceholdersResolver implements PlaceholdersResolver {
+		private PlaceholdersResolver resolver;
+
+		NonSecretsManagerPropertiesPlaceholdersResolver(Environment environment) {
+			this.resolver = new PropertySourcesPlaceholdersResolver(environment);
+		}
+
+		@Override
+		public Object resolvePlaceholders(Object value) {
+			if (value.toString().contains("sm://")) {
+				return value;
+			}
+			else {
+				return resolver.resolvePlaceholders(value);
+			}
+		}
+	}
+}

spring-cloud-gcp-autoconfigure/src/main/java/com/google/cloud/spring/autoconfigure/sql/R2dbcCloudSqlEnvironmentPostProcessor.java

@@ -0,0 +1,95 @@
+/*
+ * Copyright 2021-2022 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 com.google.cloud.spring.autoconfigure.sql;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.env.EnvironmentPostProcessor;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.MapPropertySource;
+import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
+
+/**
+ * Builds connection string for Cloud SQL through Spring R2DBC by requiring only a
+ * database and instance connection name.
+ *
+ */
+public class R2dbcCloudSqlEnvironmentPostProcessor implements EnvironmentPostProcessor {
+	private static final Log LOGGER = LogFactory.getLog(R2dbcCloudSqlEnvironmentPostProcessor.class);
+
+	@Override
+	public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) {
+		if (environment.getPropertySources().contains("bootstrap")) {
+			// Do not run in the bootstrap phase as the user configuration is not available yet
+			return;
+		}
+
+		DatabaseType databaseType = getEnabledDatabaseType(environment);
+		if (databaseType != null) {
+			PropertiesRetriever propertiesRetriever = new PropertiesRetriever(environment);
+			String r2dbcUrl = createUrl(databaseType, propertiesRetriever.getCloudSqlProperties());
+			if (LOGGER.isInfoEnabled()) {
+				LOGGER.info("Default " + databaseType.name()
+						+ " R2dbcUrl provider. Connecting to "
+						+ r2dbcUrl);
+			}
+
+			// Add default username as fallback when not specified
+			Map<String, Object> fallbackMap = new HashMap<>();
+			fallbackMap.put("spring.r2dbc.username", databaseType.getDefaultUsername());
+			environment.getPropertySources().addLast(new MapPropertySource("CLOUD_SQL_R2DBC_USERNAME", fallbackMap));
+
+			Map<String, Object> primaryMap = new HashMap<>();
+			primaryMap.put("spring.r2dbc.url", r2dbcUrl);
+			environment.getPropertySources().addFirst(new MapPropertySource("CLOUD_SQL_R2DBC_URL", primaryMap));
+		}
+	}
+
+	String createUrl(DatabaseType databaseType, GcpCloudSqlProperties sqlProperties) {
+		Assert.hasText(sqlProperties.getDatabaseName(), "A database name must be provided.");
+		Assert.hasText(sqlProperties.getInstanceConnectionName(),
+				"An instance connection name must be provided in the format <PROJECT_ID>:<REGION>:<INSTANCE_ID>.");
+
+		return String.format(databaseType.getR2dbcUrlTemplate(),
+				sqlProperties.getInstanceConnectionName(), sqlProperties.getDatabaseName());
+	}
+
+	DatabaseType getEnabledDatabaseType(ConfigurableEnvironment environment) {
+		if (Boolean.parseBoolean(environment.getProperty("spring.cloud.gcp.sql.enabled", "true"))
+				&& isOnClasspath("com.google.cloud.sql.CredentialFactory")) {
+			if (isOnClasspath("com.google.cloud.sql.core.GcpConnectionFactoryProviderMysql") &&
+					isOnClasspath("dev.miku.r2dbc.mysql.MySqlConnectionFactoryProvider")) {
+				return DatabaseType.R2DBC_MYSQL;
+			}
+			else if (isOnClasspath("com.google.cloud.sql.core.GcpConnectionFactoryProviderPostgres")
+					&& isOnClasspath("io.r2dbc.postgresql.PostgresqlConnectionFactoryProvider")) {
+				return DatabaseType.R2DBC_POSTGRESQL;
+			}
+		}
+		return null;
+	}
+
+	private boolean isOnClasspath(String className) {
+		return ClassUtils.isPresent(className, null);
+	}
+}

spring-cloud-gcp-autoconfigure/src/main/resources/META-INF/spring.factories

@@ -35,4 +35,5 @@ com.google.cloud.spring.autoconfigure.secretmanager.GcpSecretManagerBootstrapCon
 
 org.springframework.boot.env.EnvironmentPostProcessor=\
 com.google.cloud.spring.autoconfigure.sql.CloudSqlEnvironmentPostProcessor,\
+com.google.cloud.spring.autoconfigure.sql.R2dbcCloudSqlEnvironmentPostProcessor,\
 com.google.cloud.spring.autoconfigure.secretmanager.GcpSecretManagerEnvironmentPostProcessor