tolbertam commented on code in PR #2013: URL: https://github.com/apache/cassandra-java-driver/pull/2013#discussion_r1955038288
########## core/src/main/java/com/datastax/oss/driver/internal/core/addresstranslation/SubnetAddressTranslator.java: ########## @@ -0,0 +1,226 @@ +/* + * 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.internal.core.addresstranslation; + +import com.datastax.oss.driver.api.core.addresstranslation.AddressTranslator; +import com.datastax.oss.driver.api.core.config.DriverOption; +import com.datastax.oss.driver.api.core.context.DriverContext; +import com.google.common.base.Splitter; +import edu.umd.cs.findbugs.annotations.NonNull; +import inet.ipaddr.IPAddress; +import inet.ipaddr.IPAddressString; +import java.net.InetSocketAddress; +import java.util.List; +import java.util.Objects; +import java.util.Optional; +import java.util.stream.Collectors; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * This translator returns the proxy address of the private subnet containing the Cassandra node IP, + * or default address if no matching subnets, or passes through the original node address if no + * default configured. + * + * <p>The translator can be used for scenarios when all nodes are behind some kind of proxy, and + * that proxy is different for nodes located in different subnets (eg. when Cassandra is deployed in + * multiple datacenters/regions). One can use this, for example, for Cassandra on Kubernetes with + * different Cassandra datacenters deployed to different Kubernetes clusters. + */ +public class SubnetAddressTranslator implements AddressTranslator { + + private static final Logger LOG = LoggerFactory.getLogger(SubnetAddressTranslator.class); + + /** + * A map of Cassandra node subnets (CIDR notations) to target addresses, for example (note quoted + * keys): + * + * <pre> + * advanced.address-translator.subnet-addresses { + * "100.64.0.0/15" = "cassandra.datacenter1.com:9042" + * "100.66.0.0/15" = "cassandra.datacenter2.com" + * # IPv6 example: + * # "::ffff:6440:0/111" = "cassandra.datacenter1.com:9042" + * # "::ffff:6442:0/111" = "cassandra.datacenter2.com" + * } + * </pre> + * + * If configured without port, the default 9042 will be used. Also supports IPv6 subnets. Note: + * subnets must be represented as prefix blocks, see {@link inet.ipaddr.Address#isPrefixBlock()}. + */ + public static final String ADDRESS_TRANSLATOR_SUBNET_ADDRESSES = + "advanced.address-translator.subnet-addresses"; + + /** + * A default address to fallback to if Cassandra node IP isn't contained in any of the configured + * subnets. If configured without port, the default 9042 will be used. Also supports IPv6 + * addresses. + */ + public static final String ADDRESS_TRANSLATOR_DEFAULT_ADDRESS = + "advanced.address-translator.default-address"; + + public static DriverOption ADDRESS_TRANSLATOR_SUBNET_ADDRESSES_OPTION = + new DriverOption() { + @NonNull + @Override + public String getPath() { + return ADDRESS_TRANSLATOR_SUBNET_ADDRESSES; + } + }; + + public static DriverOption ADDRESS_TRANSLATOR_DEFAULT_ADDRESS_OPTION = + new DriverOption() { + @NonNull + @Override + public String getPath() { + return ADDRESS_TRANSLATOR_DEFAULT_ADDRESS; + } + }; + + private static final String DELIMITER = ":"; + private static final int DEFAULT_PORT = 9042; + + private final List<SubnetAddress> subnetAddresses; + private final Optional<InetSocketAddress> defaultAddress; + private final String logPrefix; + + public SubnetAddressTranslator(@NonNull DriverContext context) { + logPrefix = context.getSessionName(); + this.subnetAddresses = + context.getConfig().getDefaultProfile() + .getStringMap(ADDRESS_TRANSLATOR_SUBNET_ADDRESSES_OPTION).entrySet().stream() + .map( + e -> { + // Quoted and/or containing forward slashes map keys in reference.conf are read to + // strings with additional quotes, eg. 100.64.0.0/15 -> '100.64.0."0/15"' or + // "100.64.0.0/15" -> '"100.64.0.0/15"' + String subnet = e.getKey().replaceAll("\"", ""); + String address = e.getValue(); + return new SubnetAddress(subnet, address); + }) + .collect(Collectors.toList()); + this.defaultAddress = + Optional.ofNullable( + context + .getConfig() + .getDefaultProfile() + .getString(ADDRESS_TRANSLATOR_DEFAULT_ADDRESS_OPTION, null)) + .map(SubnetAddressTranslator::parseAddress); + SubnetAddressTranslator.validateSubnetsAreNotOverlapping(this.subnetAddresses); + } + + @NonNull + @Override + public InetSocketAddress translate(@NonNull InetSocketAddress address) { + InetSocketAddress translatedAddress = null; + for (SubnetAddress subnetAddress : subnetAddresses) { + if (subnetAddress.contains(address)) { + translatedAddress = subnetAddress.address; + } + } + if (translatedAddress == null && defaultAddress.isPresent()) { + translatedAddress = defaultAddress.get(); + } + if (translatedAddress == null) { + translatedAddress = address; + } + LOG.debug("[{}] Resolved {} to {}", logPrefix, address, translatedAddress); + return translatedAddress; + } + + @Override + public void close() {} + + private static InetSocketAddress parseAddress(String address) { + List<String> addressTuple = Splitter.onPattern(DELIMITER).splitToList(address); + if (addressTuple.size() == 2) { + return new InetSocketAddress(addressTuple.get(0), Integer.parseInt(addressTuple.get(1))); Review Comment: Just looking now and I realized I gave faulty advice about where to create the `InetSocketAddress`, sorry about that! I didn't consider the case where `resolve-contact-points` is true. By moving the `extract` call to `translate` it will needlessly resolve the DNS even if `resolve-contact-points` is true every time `translate` is called which we probably don't want in that case. So I think you had it right initially by creating the `InetSocketAddress` in the constructor. I think what we want to do is to call `extract` in the constructor, as that would resolve the address only once overall (instead of for each endpoint in translate). This also addresses another concern I had which is that `AddressUtils.resolve` throws a RuntimeException if the DNS can't be resolved, by moving the `extract` call back in to the constructor, I think this would be ok, as it will fail fast. For the cases where `resolve-contact-points` is false, we'll still resolve every time we attempt to connect which I think we want. I think I agree with you that maybe overloading the `resolve-contact-points` property feels wrong and creating a separate property under `advanced.address-translator` is the right thing to do. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: pr-unsubscr...@cassandra.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: pr-unsubscr...@cassandra.apache.org For additional commands, e-mail: pr-h...@cassandra.apache.org
