feat: add ClientRoutesConfig and ClientRoutesEndpoint for PrivateLink deployments

Author: nikagra

core/src/main/java/com/datastax/oss/driver/api/core/config/ClientRoutesConfig.java

@@ -0,0 +1,186 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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
+ *
+ *     http://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.datastax.oss.driver.api.core.config;
+
+import com.datastax.oss.driver.api.core.session.SessionBuilder;
+import edu.umd.cs.findbugs.annotations.NonNull;
+import edu.umd.cs.findbugs.annotations.Nullable;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+import net.jcip.annotations.Immutable;
+
+/**
+ * Configuration for client routes, used in PrivateLink-style deployments.
+ *
+ * <p>Client routes enable the driver to discover and connect to nodes through a load balancer (such
+ * as AWS PrivateLink) by reading endpoint mappings from the {@code system.client_routes} table.
+ * Each endpoint is identified by a connection ID and maps to specific node addresses.
+ *
+ * <p>This configuration is mutually exclusive with a user-provided {@link
+ * com.datastax.oss.driver.api.core.addresstranslation.AddressTranslator}. If client routes are
+ * configured, the driver will use its internal client routes handler for address translation.
+ *
+ * <p>Example usage:
+ *
+ * <pre>{@code
+ * ClientRoutesConfig config = ClientRoutesConfig.builder()
+ *     .addEndpoint(new ClientRoutesEndpoint(
+ *         UUID.fromString("12345678-1234-1234-1234-123456789012"),
+ *         "my-privatelink.us-east-1.aws.scylladb.com:9042"))
+ *     .build();
+ *
+ * CqlSession session = CqlSession.builder()
+ *     .withClientRoutesConfig(config)
+ *     .build();
+ * }</pre>
+ *
+ * @see SessionBuilder#withClientRoutesConfig(ClientRoutesConfig)
+ * @see ClientRoutesEndpoint
+ */
+@Immutable
+public class ClientRoutesConfig {
+
+  private final List<ClientRoutesEndpoint> endpoints;
+  private final String tableName;
+
+  private ClientRoutesConfig(List<ClientRoutesEndpoint> endpoints, String tableName) {
+    if (endpoints == null || endpoints.isEmpty()) {
+      throw new IllegalArgumentException("At least one endpoint must be specified");
+    }
+    this.endpoints = Collections.unmodifiableList(new ArrayList<>(endpoints));
+    this.tableName = tableName;
+  }
+
+  /**
+   * Returns the list of configured endpoints.
+   *
+   * @return an immutable list of endpoints.
+   */
+  @NonNull
+  public List<ClientRoutesEndpoint> getEndpoints() {
+    return endpoints;
+  }
+
+  /**
+   * Returns the name of the system table to query for client routes.
+   *
+   * @return the table name, or null to use the default ({@code system.client_routes}).
+   */
+  @Nullable
+  public String getTableName() {
+    return tableName;
+  }
+
+  /**
+   * Creates a new builder for constructing a {@link ClientRoutesConfig}.
+   *
+   * @return a new builder instance.
+   */
+  @NonNull
+  public static Builder builder() {
+    return new Builder();
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof ClientRoutesConfig)) {
+      return false;
+    }
+    ClientRoutesConfig that = (ClientRoutesConfig) o;
+    return endpoints.equals(that.endpoints) && Objects.equals(tableName, that.tableName);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(endpoints, tableName);
+  }
+
+  @Override
+  public String toString() {
+    return "ClientRoutesConfig{"
+        + "endpoints="
+        + endpoints
+        + ", tableName='"
+        + tableName
+        + '\''
+        + '}';
+  }
+
+  /** Builder for {@link ClientRoutesConfig}. */
+  public static class Builder {
+    private final List<ClientRoutesEndpoint> endpoints = new ArrayList<>();
+    private String tableName;
+
+    /**
+     * Adds an endpoint to the configuration.
+     *
+     * @param endpoint the endpoint to add (must not be null).
+     * @return this builder.
+     */
+    @NonNull
+    public Builder addEndpoint(@NonNull ClientRoutesEndpoint endpoint) {
+      this.endpoints.add(Objects.requireNonNull(endpoint, "endpoint must not be null"));
+      return this;
+    }
+
+    /**
+     * Sets the endpoints for the configuration, replacing any previously added endpoints.
+     *
+     * @param endpoints the endpoints to set (must not be null or empty).
+     * @return this builder.
+     */
+    @NonNull
+    public Builder withEndpoints(@NonNull List<ClientRoutesEndpoint> endpoints) {
+      Objects.requireNonNull(endpoints, "endpoints must not be null");
+      this.endpoints.clear();
+      this.endpoints.addAll(endpoints);
+      return this;
+    }
+
+    /**
+     * Sets the name of the system table to query for client routes.
+     *
+     * <p>This is primarily useful for testing. If not set, the driver will use the default table
+     * name from the configuration ({@code system.client_routes}).
+     *
+     * @param tableName the table name to use.
+     * @return this builder.
+     */
+    @NonNull
+    public Builder withTableName(@Nullable String tableName) {
+      this.tableName = tableName;
+      return this;
+    }
+
+    /**
+     * Builds the {@link ClientRoutesConfig} with the configured endpoints and table name.
+     *
+     * @return the new configuration instance.
+     * @throws IllegalArgumentException if no endpoints have been added.
+     */
+    @NonNull
+    public ClientRoutesConfig build() {
+      return new ClientRoutesConfig(endpoints, tableName);
+    }
+  }
+}

core/src/main/java/com/datastax/oss/driver/api/core/config/ClientRoutesEndpoint.java

@@ -0,0 +1,103 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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
+ *
+ *     http://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.datastax.oss.driver.api.core.config;
+
+import edu.umd.cs.findbugs.annotations.NonNull;
+import edu.umd.cs.findbugs.annotations.Nullable;
+import java.util.Objects;
+import java.util.UUID;
+import net.jcip.annotations.Immutable;
+
+/**
+ * Represents a client routes endpoint for PrivateLink-style deployments.
+ *
+ * <p>Each endpoint corresponds to a connection ID in the {@code system.client_routes} table, with
+ * an optional connection address that can be used as a seed host for initial connection.
+ */
+@Immutable
+public class ClientRoutesEndpoint {
+
+  private final UUID connectionId;
+  private final String connectionAddr;
+
+  /**
+   * Creates a new endpoint with the given connection ID and no connection address.
+   *
+   * @param connectionId the connection ID (must not be null).
+   */
+  public ClientRoutesEndpoint(@NonNull UUID connectionId) {
+    this(connectionId, null);
+  }
+
+  /**
+   * Creates a new endpoint with the given connection ID and connection address.
+   *
+   * @param connectionId the connection ID (must not be null).
+   * @param connectionAddr the connection address to use as a seed host (may be null).
+   */
+  public ClientRoutesEndpoint(@NonNull UUID connectionId, @Nullable String connectionAddr) {
+    this.connectionId = Objects.requireNonNull(connectionId, "connectionId must not be null");
+    this.connectionAddr = connectionAddr;
+  }
+
+  /** Returns the connection ID for this endpoint. */
+  @NonNull
+  public UUID getConnectionId() {
+    return connectionId;
+  }
+
+  /**
+   * Returns the connection address for this endpoint, or null if not specified.
+   *
+   * <p>When provided and no explicit contact points are given to the session builder, this address
+   * will be used as a seed host for the initial connection.
+   */
+  @Nullable
+  public String getConnectionAddr() {
+    return connectionAddr;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof ClientRoutesEndpoint)) {
+      return false;
+    }
+    ClientRoutesEndpoint that = (ClientRoutesEndpoint) o;
+    return connectionId.equals(that.connectionId)
+        && Objects.equals(connectionAddr, that.connectionAddr);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(connectionId, connectionAddr);
+  }
+
+  @Override
+  public String toString() {
+    return "ClientRoutesEndpoint{"
+        + "connectionId="
+        + connectionId
+        + ", connectionAddr='"
+        + connectionAddr
+        + '\''
+        + '}';
+  }
+}

core/src/main/java/com/datastax/oss/driver/api/core/config/DefaultDriverOption.java

@@ -449,6 +449,17 @@ public enum DefaultDriverOption implements DriverOption {
    */
   ADDRESS_TRANSLATOR_CLASS("advanced.address-translator.class"),
 
+  /**
+   * The name of the system table to query for client routes information.
+   *
+   * <p>This is used when client routes are configured programmatically via {@link
+   * com.datastax.oss.driver.api.core.session.SessionBuilder#withClientRoutesConfig}. The default
+   * value is {@code system.client_routes}.
+   *
+   * <p>Value-type: {@link String}
+   */
+  CLIENT_ROUTES_TABLE_NAME("advanced.client-routes.table-name"),
+
   /**
    * The native protocol version to use.
    *

core/src/main/java/com/datastax/oss/driver/api/core/config/OptionsMap.java

@@ -396,6 +396,7 @@ protected static void fillWithDriverDefaults(OptionsMap map) {
     map.put(
         TypedDriverOption.LOAD_BALANCING_DEFAULT_LWT_REQUEST_ROUTING_METHOD,
         "PRESERVE_REPLICA_ORDER");
+    map.put(TypedDriverOption.CLIENT_ROUTES_TABLE_NAME, "system.client_routes");
   }
 
   @Immutable

core/src/main/java/com/datastax/oss/driver/api/core/config/TypedDriverOption.java

@@ -939,6 +939,9 @@ public String toString() {
           DefaultDriverOption.LOAD_BALANCING_DEFAULT_LWT_REQUEST_ROUTING_METHOD,
           GenericType.STRING);
 
+  public static final TypedDriverOption<String> CLIENT_ROUTES_TABLE_NAME =
+      new TypedDriverOption<>(DefaultDriverOption.CLIENT_ROUTES_TABLE_NAME, GenericType.STRING);
+
   private static Iterable<TypedDriverOption<?>> introspectBuiltInValues() {
     try {
       ImmutableList.Builder<TypedDriverOption<?>> result = ImmutableList.builder();