chore: Use domain name from JDBC URL for Postgres and Mysql, Part of #2043

jdbc/mariadb/src/main/java/com/google/cloud/sql/mariadb/SocketFactory.java

@@ -37,6 +37,7 @@ public class SocketFactory extends ConfigurableSocketFactory {
   }
 
   private Configuration conf;
+  private String host;
 
   /** Instantiate a socket factory. */
   public SocketFactory() {}
@@ -45,13 +46,14 @@ public SocketFactory() {}
   public void setConfiguration(Configuration conf, String host) {
     // Ignore the hostname
     this.conf = conf;
+    this.host = host;
   }
 
   @Override
   public Socket createSocket() throws IOException {
     try {
       return InternalConnectorRegistry.getInstance()
-          .connect(ConnectionConfig.fromConnectionProperties(conf.nonMappedOptions()));
+          .connect(ConnectionConfig.fromConnectionProperties(conf.nonMappedOptions(), host));
     } catch (InterruptedException e) {
       throw new RuntimeException(e);
     }

jdbc/mysql-j-8/src/main/java/com/google/cloud/sql/mysql/SocketFactory.java

@@ -60,7 +60,7 @@ public <T extends Closeable> T connect(
     T socket =
         (T)
             InternalConnectorRegistry.getInstance()
-                .connect(ConnectionConfig.fromConnectionProperties(props));
+                .connect(ConnectionConfig.fromConnectionProperties(props, host));
     return socket;
   }
 

jdbc/mysql-j-8/src/test/java/com/google/cloud/sql/mysql/JdbcMysqlJ8DomainNameIntegrationTests.java

@@ -0,0 +1,104 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * 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.sql.mysql;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.common.truth.Truth.assertWithMessage;
+
+import com.google.cloud.sql.ConnectorConfig;
+import com.google.cloud.sql.ConnectorRegistry;
+import com.google.common.collect.ImmutableList;
+import com.zaxxer.hikari.HikariConfig;
+import com.zaxxer.hikari.HikariDataSource;
+import java.sql.*;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Properties;
+import java.util.concurrent.TimeUnit;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.Timeout;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+public class JdbcMysqlJ8DomainNameIntegrationTests {
+
+  private static final String CONNECTION_NAME = System.getenv("MYSQL_CONNECTION_NAME");
+  private static final String DB_NAME = System.getenv("MYSQL_DB");
+  private static final String DB_USER = System.getenv("MYSQL_USER");
+  private static final String DB_PASSWORD = System.getenv("MYSQL_PASS");
+  private static final ImmutableList<String> requiredEnvVars =
+      ImmutableList.of("MYSQL_USER", "MYSQL_PASS", "MYSQL_DB", "MYSQL_CONNECTION_NAME");
+  @Rule public Timeout globalTimeout = new Timeout(80, TimeUnit.SECONDS);
+  private HikariDataSource connectionPool;
+
+  @BeforeClass
+  public static void checkEnvVars() {
+    // Check that required env vars are set
+    requiredEnvVars.forEach(
+        (varName) ->
+            assertWithMessage(
+                    String.format(
+                        "Environment variable '%s' must be set to perform these tests.", varName))
+                .that(System.getenv(varName))
+                .isNotEmpty());
+  }
+
+  @Before
+  public void setUpPool() throws SQLException {
+    // Set up URL parameters
+    String jdbcURL = String.format("jdbc:mysql://db.example.com/%s", DB_NAME);
+    Properties connProps = new Properties();
+    connProps.setProperty("user", DB_USER);
+    connProps.setProperty("password", DB_PASSWORD);
+    connProps.setProperty("socketFactory", "com.google.cloud.sql.mysql.SocketFactory");
+
+    // Register a resolver that resolves `db.example.com` to the connection name
+    connProps.setProperty("cloudSqlNamedConnector", "resolver-test");
+    ConnectorRegistry.register(
+        "resolver-test",
+        new ConnectorConfig.Builder()
+            .withInstanceNameResolver((n) -> "db.example.com".equals(n) ? CONNECTION_NAME : null)
+            .build());
+
+    // Initialize connection pool
+    HikariConfig config = new HikariConfig();
+    config.setJdbcUrl(jdbcURL);
+    config.setDataSourceProperties(connProps);
+    config.setConnectionTimeout(10000); // 10s
+
+    this.connectionPool = new HikariDataSource(config);
+  }
+
+  @Test
+  public void pooledConnectionTest() throws SQLException {
+
+    List<Timestamp> rows = new ArrayList<>();
+    try (Connection conn = connectionPool.getConnection()) {
+      try (PreparedStatement selectStmt = conn.prepareStatement("SELECT NOW() as TS")) {
+        ResultSet rs = selectStmt.executeQuery();
+        while (rs.next()) {
+          rows.add(rs.getTimestamp("TS"));
+        }
+      }
+    }
+    assertThat(rows.size()).isEqualTo(1);
+  }
+}

jdbc/mysql-j-8/src/test/java/com/google/cloud/sql/mysql/JdbcMysqlJ8IntegrationTests.java

@@ -62,7 +62,7 @@ public static void checkEnvVars() {
   @Before
   public void setUpPool() throws SQLException {
     // Set up URL parameters
-    String jdbcURL = String.format("jdbc:mysql:///%s", DB_NAME);
+    String jdbcURL = String.format("jdbc:mysql://db.example.com/%s", DB_NAME);
     Properties connProps = new Properties();
     connProps.setProperty("user", DB_USER);
     connProps.setProperty("password", DB_PASSWORD);

jdbc/postgres/src/main/java/com/google/cloud/sql/postgres/SocketFactory.java

@@ -38,6 +38,9 @@ public class SocketFactory extends javax.net.SocketFactory {
   private static final String DEPRECATED_SOCKET_ARG = "SocketFactoryArg";
   private static final String POSTGRES_SUFFIX = "/.s.PGSQL.5432";
 
+  /** The connection property containing the hostname from the JDBC url. */
+  private static final String POSTGRES_HOST_PROP = "PGHOST";
+
   private final Properties props;
 
   static {
@@ -83,7 +86,9 @@ private static Properties createDefaultProperties(String instanceName) {
   public Socket createSocket() throws IOException {
     try {
       return InternalConnectorRegistry.getInstance()
-          .connect(ConnectionConfig.fromConnectionProperties(props));
+          .connect(
+              ConnectionConfig.fromConnectionProperties(
+                  props, props.getProperty(POSTGRES_HOST_PROP)));
     } catch (InterruptedException e) {
       throw new RuntimeException(e);
     }

jdbc/postgres/src/test/java/com/google/cloud/sql/postgres/JdbcPostgresDomainNameIntegrationTests.java

@@ -0,0 +1,104 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * 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.sql.postgres;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.common.truth.Truth.assertWithMessage;
+
+import com.google.cloud.sql.ConnectorConfig;
+import com.google.cloud.sql.ConnectorRegistry;
+import com.google.common.collect.ImmutableList;
+import com.zaxxer.hikari.HikariConfig;
+import com.zaxxer.hikari.HikariDataSource;
+import java.sql.*;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Properties;
+import java.util.concurrent.TimeUnit;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.Timeout;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+public class JdbcPostgresDomainNameIntegrationTests {
+
+  private static final String CONNECTION_NAME = System.getenv("POSTGRES_CONNECTION_NAME");
+  private static final String DB_NAME = System.getenv("POSTGRES_DB");
+  private static final String DB_USER = System.getenv("POSTGRES_USER");
+  private static final String DB_PASSWORD = System.getenv("POSTGRES_PASS");
+  private static final ImmutableList<String> requiredEnvVars =
+      ImmutableList.of("POSTGRES_USER", "POSTGRES_PASS", "POSTGRES_DB", "POSTGRES_CONNECTION_NAME");
+  @Rule public Timeout globalTimeout = new Timeout(80, TimeUnit.SECONDS);
+
+  private HikariDataSource connectionPool;
+
+  @BeforeClass
+  public static void checkEnvVars() {
+    // Check that required env vars are set
+    requiredEnvVars.forEach(
+        (varName) ->
+            assertWithMessage(
+                    String.format(
+                        "Environment variable '%s' must be set to perform these tests.", varName))
+                .that(System.getenv(varName))
+                .isNotEmpty());
+  }
+
+  @Before
+  public void setUpPool() throws SQLException {
+    // Set up URL parameters
+    String jdbcURL = String.format("jdbc:postgresql://db.example.com/%s", DB_NAME);
+    Properties connProps = new Properties();
+    connProps.setProperty("user", DB_USER);
+    connProps.setProperty("password", DB_PASSWORD);
+    connProps.setProperty("socketFactory", "com.google.cloud.sql.postgres.SocketFactory");
+    connProps.setProperty("cloudSqlNamedConnector", "resolver-test");
+
+    ConnectorRegistry.register(
+        "resolver-test",
+        new ConnectorConfig.Builder()
+            .withInstanceNameResolver((n) -> "db.example.com".equals(n) ? CONNECTION_NAME : null)
+            .build());
+
+    // Initialize connection pool
+    HikariConfig config = new HikariConfig();
+    config.setJdbcUrl(jdbcURL);
+    config.setDataSourceProperties(connProps);
+    config.setConnectionTimeout(10000); // 10s
+
+    this.connectionPool = new HikariDataSource(config);
+  }
+
+  @Test
+  public void pooledConnectionTest() throws SQLException {
+
+    List<Timestamp> rows = new ArrayList<>();
+    try (Connection conn = connectionPool.getConnection()) {
+      try (PreparedStatement selectStmt = conn.prepareStatement("SELECT NOW() as TS")) {
+        ResultSet rs = selectStmt.executeQuery();
+        while (rs.next()) {
+          rows.add(rs.getTimestamp("TS"));
+        }
+      }
+    }
+    assertThat(rows.size()).isEqualTo(1);
+  }
+}

jdbc/postgres/src/test/java/com/google/cloud/sql/postgres/JdbcPostgresIntegrationTests.java

@@ -63,7 +63,7 @@ public static void checkEnvVars() {
   @Before
   public void setUpPool() throws SQLException {
     // Set up URL parameters
-    String jdbcURL = String.format("jdbc:postgresql:///%s", DB_NAME);
+    String jdbcURL = String.format("jdbc:postgresql://db.example.com/%s", DB_NAME);
     Properties connProps = new Properties();
     connProps.setProperty("user", DB_USER);
     connProps.setProperty("password", DB_PASSWORD);