jahstreet commented on code in PR #2013: URL: https://github.com/apache/cassandra-java-driver/pull/2013#discussion_r1955722161
########## 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: What is actually the downside of resolving on each #translate? I see 2 potential concerns: 1. Performance, which is negligible cause we don't do it that frequently (not on every query, only on metadata refreshes) and also we run it on a separate admin thread, which doesn't explicitly impact queries performance. 2. On metadata refreshes, if we resolve endpoint of existing Node to different IP, then we overwrite it in the Node object and the code that relies on search by EndPoint rather than by host ID (or do similar quirks) might get things wrong (maybe we don't have it, but it feels like such assumptions might have been somewhere, I'm just not yet that much familiar with the code). Do you remember anything of that sort in the codebase? To conclude, if we go with either `resolve once on session init (translator constructor)` or `resolve on each connection`, we guard against both. -- 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. 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