feat: Metadata Exchange support for the Java connector. (#2200)

This is the client-side implementation of the metadata exchange protocol for Cloud SQL instances. This will
allow connectors to pass metadata about the connection to the Cloud SQL instance while the connection
is being established.

In particular, this is a part of resolving the issues with the Auth Proxy connecting to MySQL instances that
use the caching_sha2_password extension. (See GoogleCloudPlatform/cloud-sql-proxy#2317)

This does not update the default MDX behavior yet. That will be added in #2207

Author: hessjcg

.gitignore

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

.kokoro/check_coverage.sh

@@ -16,8 +16,23 @@
 # `-e` enables the script to automatically fail when a command fails
 set -e
 
-export CUR_COVER=$(cat core/target/site/jacoco/index.html | grep -o 'Total[^%]*' | sed 's/<.*>//; s/Total//')
-echo "Current Coverage is $CUR_COVER%"
+# Calculate total coverage, skipping the generated protobuf file.
+# The CSV file generated by Jacoco has the test coverage for each. We use AWK to process this CSV file.
+# here's what the AWK program means:
+#
+#     NR > 1 &&                                   Skip the first line, it only has field names
+#       $3 != "com.google.cloud.sql.core.mdx"     Skip any line for class in the protobuf generated package 'mdx'
+#     { covered += $6; total += $6+$5; }          For each line add a running sum of covered lines and total lines
+#     END { printf "%2.f", covered/total * 100}'  At the end, print out the coverage percentage, no decimals
+#
+
+CUR_COVER=$( awk -F,  \
+  'NR > 1 && $3 != "com.google.cloud.sql.core.mdx" { covered += $6; total += $6+$5; } END { printf "%2.f", covered/total * 100}' \
+  < "core/target/site/jacoco/jacoco.csv")
+
 if [ "$CUR_COVER" -lt 75  ]; then
+  echo "FAIL: Current Coverage is $CUR_COVER%, less than the required 75%"
   exit 1;
+else
+  echo "PASS: Current Coverage is $CUR_COVER%"
 fi

build.sh

@@ -42,7 +42,7 @@ function test() {
     sudo ifconfig lo0 alias 127.0.0.2 up
     sudo ifconfig lo0 alias 127.0.0.3 up
   fi
-  mvn install
+  mvn -P coverage test
 }
 
 ## e2e - Runs end-to-end integration tests.

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 mdxClientProtocolType) {
+    return new ConnectionConfig(
+        cloudSqlInstance,
+        namedConnector,
+        unixSocketPath,
+        ipTypes,
+        authType,
+        unixSocketPathSuffix,
+        domainName,
+        connectorConfig,
+        mdxClientProtocolType);
   }
 
   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(