feat: Metadata Exchange support for the Java connector.

Author: hessjcg

.gitignore

@@ -73,3 +73,4 @@ artman-genfiles
 *.zip
 *.tar.gz
 *.rar
+.tools

core/pom.xml

@@ -210,11 +210,53 @@
       <artifactId>logback-classic</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+        <groupId>com.google.protobuf</groupId>
+        <artifactId>protobuf-java</artifactId>
+    </dependency>
 
   </dependencies>
 
   <build>
     <plugins>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>build-helper-maven-plugin</artifactId>
+        <version>3.3.0</version>
+        <executions>
+          <execution>
+            <id>test</id>
+            <phase>generate-sources</phase>
+            <goals>
+              <goal>add-source</goal>
+            </goals>
+            <configuration>
+              <sources>
+                <source>${project.basedir}/target/generated-sources</source>
+              </sources>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <groupId>com.github.os72</groupId>
+        <artifactId>protoc-jar-maven-plugin</artifactId>
+        <version>3.11.4</version>
+        <executions>
+          <execution>
+            <phase>generate-sources</phase>
+            <goals>
+              <goal>run</goal>
+            </goals>
+            <configuration>
+              <optimizeCodegen>false</optimizeCodegen>
+              <protocVersion>3.23.0</protocVersion>
+              <includeStdTypes>true</includeStdTypes>
+              <outputOptions></outputOptions>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-jar-plugin</artifactId>

core/src/main/java/com/google/cloud/sql/core/ConnectionConfig.java

@@ -54,6 +54,7 @@ public class ConnectionConfig {
   public static final List<IpType> DEFAULT_IP_TYPE_LIST =
       Arrays.asList(IpType.PUBLIC, IpType.PRIVATE);
   public static final String CLOUD_SQL_GOOGLE_CREDENTIALS_PATH = "cloudSqlGoogleCredentialsPath";
+  public static final String MDX_CLIENT_PROTOCOL_TYPE = "mdxClientProtocolType";
 
   private final ConnectorConfig connectorConfig;
   private final String cloudSqlInstance;
@@ -64,6 +65,7 @@ public class ConnectionConfig {
   private final AuthType authType;
   private final String unixSocketPathSuffix;
   private final String domainName;
+  private final String mdxClientProtocolType;
 
   /** Create a new ConnectionConfig from the well known JDBC Connection properties. */
   public static ConnectionConfig fromConnectionProperties(Properties props) {
@@ -116,6 +118,9 @@ public static ConnectionConfig fromConnectionProperties(Properties props, String
             ? RefreshStrategy.LAZY
             : RefreshStrategy.BACKGROUND;
 
+    final String mdxClientProtocolType =
+        props.getProperty(ConnectionConfig.MDX_CLIENT_PROTOCOL_TYPE);
+
     return new ConnectionConfig(
         csqlInstanceName,
         namedConnection,
@@ -133,7 +138,8 @@ public static ConnectionConfig fromConnectionProperties(Properties props, String
             .withAdminQuotaProject(adminQuotaProject)
             .withUniverseDomain(universeDomain)
             .withRefreshStrategy(refreshStrategy)
-            .build());
+            .build(),
+        mdxClientProtocolType);
   }
 
   /**
@@ -197,7 +203,8 @@ private ConnectionConfig(
       AuthType authType,
       String unixSocketPathSuffix,
       String domainName,
-      ConnectorConfig connectorConfig) {
+      ConnectorConfig connectorConfig,
+      String mdxClientProtocolType) {
     this.cloudSqlInstance = cloudSqlInstance;
     this.namedConnector = namedConnector;
     this.unixSocketPath = unixSocketPath;
@@ -206,6 +213,7 @@ private ConnectionConfig(
     this.connectorConfig = connectorConfig;
     this.authType = authType;
     this.domainName = domainName;
+    this.mdxClientProtocolType = mdxClientProtocolType;
   }
 
   /** Creates a new instance of the ConnectionConfig with an updated connectorConfig. */
@@ -218,7 +226,8 @@ public ConnectionConfig withConnectorConfig(ConnectorConfig config) {
         authType,
         unixSocketPathSuffix,
         domainName,
-        config);
+        config,
+        mdxClientProtocolType);
   }
 
   /** Creates a new instance of the ConnectionConfig with an updated cloudSqlInstance. */
@@ -231,7 +240,8 @@ public ConnectionConfig withCloudSqlInstance(String newCloudSqlInstance) {
         authType,
         unixSocketPathSuffix,
         domainName,
-        connectorConfig);
+        connectorConfig,
+        mdxClientProtocolType);
   }
 
   /** Creates a new instance of the ConnectionConfig with an updated cloudSqlInstance. */
@@ -244,7 +254,22 @@ public ConnectionConfig withDomainName(String domainName) {
         authType,
         unixSocketPathSuffix,
         domainName,
-        connectorConfig);
+        connectorConfig,
+        mdxClientProtocolType);
+  }
+
+  /** Creates a new instance of the ConnectionConfig with an updated clientProtocolType. */
+  public ConnectionConfig withMdxClientProtocolType(String clientProtocolType) {
+    return new ConnectionConfig(
+        cloudSqlInstance,
+        namedConnector,
+        unixSocketPath,
+        ipTypes,
+        authType,
+        unixSocketPathSuffix,
+        domainName,
+        connectorConfig,
+        clientProtocolType);
   }
 
   public String getNamedConnector() {
@@ -279,6 +304,10 @@ public String getDomainName() {
     return domainName;
   }
 
+  public String getMdxClientProtocolType() {
+    return mdxClientProtocolType;
+  }
+
   /** The builder for the ConnectionConfig. */
   public static class Builder {
 
@@ -290,6 +319,7 @@ public static class Builder {
     private ConnectorConfig connectorConfig = new ConnectorConfig.Builder().build();
     private AuthType authType = DEFAULT_AUTH_TYPE;
     private String domainName;
+    private String mdxClientProtocolType;
 
     /** Chained setter for CloudSqlInstance field. */
     public Builder withCloudSqlInstance(String cloudSqlInstance) {
@@ -345,6 +375,12 @@ public Builder withUnixSocketPathSuffix(String unixSocketPathSuffix) {
       return this;
     }
 
+    /** Chained setter for MdxClientProtocolType field. */
+    public Builder withMdxClientProtocolType(String mdxClientProtocolType) {
+      this.mdxClientProtocolType = mdxClientProtocolType;
+      return this;
+    }
+
     /** Builds a new instance of {@code ConnectionConfig}. */
     public ConnectionConfig build() {
       return new ConnectionConfig(
@@ -355,7 +391,8 @@ public ConnectionConfig build() {
           authType,
           unixSocketPathSuffix,
           domainName,
-          connectorConfig);
+          connectorConfig,
+          mdxClientProtocolType);
     }
   }
 }

core/src/main/java/com/google/cloud/sql/core/ConnectionInfo.java

@@ -75,6 +75,7 @@ ConnectionMetadata toConnectionMetadata(
         preferredIp,
         sslData.getKeyManagerFactory(),
         sslData.getTrustManagerFactory(),
-        sslData.getSslContext());
+        sslData.getSslContext(),
+        instanceMetadata.getMdxProtocolSupport());
   }
 }

core/src/main/java/com/google/cloud/sql/core/ConnectionInfoRepositoryFactory.java

@@ -23,4 +23,6 @@
 interface ConnectionInfoRepositoryFactory {
 
   ConnectionInfoRepository create(HttpRequestInitializer credentials, ConnectorConfig config);
+
+  String getUserAgents();
 }

core/src/main/java/com/google/cloud/sql/core/ConnectionMetadata.java

@@ -16,6 +16,7 @@
 
 package com.google.cloud.sql.core;
 
+import java.util.List;
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.SSLContext;
 import javax.net.ssl.TrustManagerFactory;
@@ -29,18 +30,21 @@ public class ConnectionMetadata {
   private final KeyManagerFactory keyManagerFactory;
   private final TrustManagerFactory trustManagerFactory;
   private final SSLContext sslContext;
+  private final List<String> mdxProtocolSupport;
 
   /** Construct an immutable ConnectionMetadata. */
   public ConnectionMetadata(
       String preferredIpAddress,
       KeyManagerFactory keyManagerFactory,
       TrustManagerFactory trustManagerFactory,
-      SSLContext sslContext) {
+      SSLContext sslContext,
+      List<String> mdxProtocolSupport) {
 
     this.preferredIpAddress = preferredIpAddress;
     this.keyManagerFactory = keyManagerFactory;
     this.trustManagerFactory = trustManagerFactory;
     this.sslContext = sslContext;
+    this.mdxProtocolSupport = mdxProtocolSupport;
   }
 
   public String getPreferredIpAddress() {
@@ -58,4 +62,12 @@ public TrustManagerFactory getTrustManagerFactory() {
   public SSLContext getSslContext() {
     return sslContext;
   }
+
+  public List<String> getMdxProtocolSupport() {
+    return mdxProtocolSupport;
+  }
+
+  public boolean isMdxClientProtocolTypeSupport() {
+    return mdxProtocolSupport != null && mdxProtocolSupport.contains("CLIENT_PROTOCOL_TYPE");
+  }
 }

core/src/main/java/com/google/cloud/sql/core/Connector.java

@@ -53,6 +53,7 @@ class Connector {
 
   private final InstanceConnectionNameResolver instanceNameResolver;
   private final Timer instanceNameResolverTimer;
+  private final ProtocolHandler mdxProtocolHandler;
 
   Connector(
       ConnectorConfig config,
@@ -63,7 +64,8 @@ class Connector {
       long minRefreshDelayMs,
       long refreshTimeoutMs,
       int serverProxyPort,
-      InstanceConnectionNameResolver instanceNameResolver) {
+      InstanceConnectionNameResolver instanceNameResolver,
+      ProtocolHandler mdxProtocolHandler) {
     this.config = config;
 
     this.adminApi =
@@ -75,6 +77,7 @@ class Connector {
     this.serverProxyPort = serverProxyPort;
     this.instanceNameResolver = instanceNameResolver;
     this.instanceNameResolverTimer = new Timer("InstanceNameResolverTimer", true);
+    this.mdxProtocolHandler = mdxProtocolHandler;
   }
 
   public ConnectorConfig getConfig() {
@@ -137,6 +140,11 @@ Socket connect(ConnectionConfig config, long timeoutMs) throws IOException {
         throw e;
       }
 
+      if (metadata.isMdxClientProtocolTypeSupport()
+          && !Strings.isNullOrEmpty(config.getMdxClientProtocolType())) {
+        socket = mdxProtocolHandler.connect(socket, config.getMdxClientProtocolType());
+      }
+
       logger.debug(String.format("[%s] Connected to instance successfully.", instanceIp));
       instance.addSocket(socket);
 

core/src/main/java/com/google/cloud/sql/core/DefaultConnectionInfoRepository.java

@@ -348,7 +348,8 @@ private InstanceMetadata fetchMetadata(CloudSqlInstanceName instanceName, AuthTy
             instanceCaCertificates,
             isCasManagedCertificate(instanceMetadata.getServerCaMode()),
             serverName,
-            pscEnabled);
+            pscEnabled,
+            instanceMetadata.getMdxProtocolSupport());
       } catch (CertificateException ex) {
         throw new RuntimeException(
             String.format(

core/src/main/java/com/google/cloud/sql/core/DefaultConnectionInfoRepositoryFactory.java

@@ -48,6 +48,11 @@ public DefaultConnectionInfoRepository create(
     return new DefaultConnectionInfoRepository(adminApiBuilder);
   }
 
+  @Override
+  public String getUserAgents() {
+    return this.userAgents;
+  }
+
   private SQLAdmin getApiBuilder(
       HttpRequestInitializer requestInitializer, ConnectorConfig config) {
     HttpTransport httpTransport;

core/src/main/java/com/google/cloud/sql/core/InstanceMetadata.java

@@ -30,20 +30,23 @@ class InstanceMetadata {
   private final boolean casManagedCertificate;
   private final String dnsName;
   private final boolean pscEnabled;
+  private final List<String> mdxProtocolSupport;
 
   InstanceMetadata(
       CloudSqlInstanceName instanceName,
       Map<IpType, String> ipAddrs,
       List<Certificate> instanceCaCertificates,
       boolean casManagedCertificate,
       String dnsName,
-      boolean pscEnabled) {
+      boolean pscEnabled,
+      List<String> mdxProtocolSupport) {
     this.instanceName = instanceName;
     this.ipAddrs = ipAddrs;
     this.instanceCaCertificates = instanceCaCertificates;
     this.casManagedCertificate = casManagedCertificate;
     this.dnsName = dnsName;
     this.pscEnabled = pscEnabled;
+    this.mdxProtocolSupport = mdxProtocolSupport;
   }
 
   Map<IpType, String> getIpAddrs() {
@@ -69,4 +72,8 @@ public boolean isPscEnabled() {
   public CloudSqlInstanceName getInstanceName() {
     return instanceName;
   }
+
+  public List<String> getMdxProtocolSupport() {
+    return mdxProtocolSupport;
+  }
 }