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 and driver -->
+        <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 and driver -->
+        <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

@@ -27,14 +27,8 @@
 import org.apache.commons.logging.Log;
 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;
@@ -62,24 +56,8 @@ public void postProcessEnvironment(
         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()) {
@@ -108,7 +86,7 @@ public void postProcessEnvironment(
           .getPropertySources()
           .addFirst(new MapPropertySource("CLOUD_SQL_DATA_SOURCE_URL", primaryMap));
 
-      setCredentials(sqlProperties, gcpProperties);
+      setCredentials(sqlProperties, propertiesRetriever.getGcpProperties());
 
       // support usage metrics
       CoreSocketFactory.setApplicationName(
@@ -191,22 +169,4 @@ 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

@@ -24,6 +24,7 @@ public enum DatabaseType {
       "jdbc:mysql://google/%s?"
           + "socketFactory=com.google.cloud.sql.mysql.SocketFactory"
           + "&cloudSqlInstance=%s",
+      "r2dbc:gcp:mysql://%s/%s",
       "root"),
 
   /** Postgresql constants. */
@@ -32,17 +33,25 @@ public enum DatabaseType {
       "jdbc:postgresql://google/%s?"
           + "socketFactory=com.google.cloud.sql.postgres.SocketFactory"
           + "&cloudSqlInstance=%s",
+      "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;
   }
 
@@ -54,6 +63,10 @@ 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 +1,77 @@
+/*
+ * 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 +1,115 @@
+/*
+ * 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());
+  }
+
+  /**
+   * Returns {@link DatabaseType} constant based on whether mySQL or postgreSQL R2DBC driver and
+   * connector dependencies are present on the classpath. Returns null if Cloud SQL is not enabled
+   * in Spring Cloud GCP, CredentialFactory is not present or ConnectionFactory (which is used to
+   * enable Spring R2DBC auto-configuration) is not present.
+   *
+   * @param environment environment to post-process
+   * @return database type
+   */
+  DatabaseType getEnabledDatabaseType(ConfigurableEnvironment environment) {
+    if (isR2dbcEnabled(environment)
+        && isOnClasspath("com.google.cloud.sql.CredentialFactory")
+        && isOnClasspath("io.r2dbc.spi.ConnectionFactory")) {
+      if (isOnClasspath("com.google.cloud.sql.core.GcpConnectionFactoryProviderMysql")
+          && isOnClasspath("dev.miku.r2dbc.mysql.MySqlConnectionFactoryProvider")) {
+        return DatabaseType.MYSQL;
+      } else if (isOnClasspath("com.google.cloud.sql.core.GcpConnectionFactoryProviderPostgres")
+          && isOnClasspath("io.r2dbc.postgresql.PostgresqlConnectionFactoryProvider")) {
+        return DatabaseType.POSTGRESQL;
+      }
+    }
+    return null;
+  }
+
+  private boolean isOnClasspath(String className) {
+    return ClassUtils.isPresent(className, null);
+  }
+
+  private boolean isR2dbcEnabled(ConfigurableEnvironment environment) {
+    return Boolean.parseBoolean(environment.getProperty("spring.cloud.gcp.sql.enabled", "true"))
+        && Boolean.parseBoolean(
+            environment.getProperty("spring.cloud.gcp.sql.r2dbc.enabled", "true"));
+  }
+}

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