aratno commented on code in PR #2013:
URL:
https://github.com/apache/cassandra-java-driver/pull/2013#discussion_r1958529763
##########
manual/core/address_resolution/README.md:
##########
@@ -118,6 +118,59 @@ datastax-java-driver.advanced.address-translator.class =
com.mycompany.MyAddress
Note: the contact points provided while creating the `CqlSession` are not
translated, only addresses
retrieved from or sent by Cassandra nodes are.
+### Fixed proxy hostname
+
+If your client applications access Cassandra through some kind of proxy (eg.
with AWS PrivateLink when all Cassandra
+nodes are exposed via one hostname pointing to AWS Endpoint), you can
configure driver with
+`FixedHostNameAddressTranslator` to always translate all node addresses to
that same proxy hostname, no matter what IP
+address a node has but still using its native transport port.
+
+To use it, specify the following in the [configuration](../configuration):
+
+```
+datastax-java-driver.advanced.address-translator.class =
FixedHostNameAddressTranslator
+advertised-hostname = proxyhostname
+```
+
+### Fixed proxy hostname per subnet
+
+When running Cassandra in a private network and accessing it from outside of
that private network via some kind of
+proxy, we have an option to use `FixedHostNameAddressTranslator`. But for
multi-datacenter Cassandra deployments, we
+want to have more control over routing queries to a specific datacenter (eg.
for optimizing latencies), which requires
+setting up a separate proxy per datacenter.
+
+Normally, each Cassandra datacenter nodes are deployed to a different subnet
to support internode communications in the
+cluster and avoid IP address collisions. So when Cassandra broadcasts its
nodes IP addresses, we can determine which
+datacenter that node belongs to by checking its IP address against the given
datacenter subnet.
+
+For such scenarios you can use `SubnetAddressTranslator` to translate node IPs
to the datacenter proxy address
+associated with it.
+
+To use it, specify the following in the [configuration](../configuration):
+```
+datastax-java-driver.advanced.address-translator {
+ class = SubnetAddressTranslator
+ subnet-addresses {
+ "100.64.0.0/15" = "cassandra.datacenter1.com:9042"
+ "100.66.0.0/15" = "cassandra.datacenter2.com:9042"
Review Comment:
Thanks for including port configuration here -
FixedHostNameAddressTranslator doesn't support ports, so even for
single-hostname translation this can be a better option
##########
core/src/main/java/com/datastax/oss/driver/internal/core/addresstranslation/SubnetAddressTranslator.java:
##########
@@ -0,0 +1,236 @@
+/*
+ * 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.datastax.oss.driver.internal.core.util.AddressUtils;
+import edu.umd.cs.findbugs.annotations.NonNull;
+import edu.umd.cs.findbugs.annotations.Nullable;
+import inet.ipaddr.IPAddress;
+import inet.ipaddr.IPAddressString;
+import java.net.InetSocketAddress;
+import java.util.List;
+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:9042"
+ * # IPv6 example:
+ * # "::ffff:6440:0/111" = "cassandra.datacenter1.com:9042"
+ * # "::ffff:6442:0/111" = "cassandra.datacenter2.com:9042"
+ * }
+ * </pre>
+ *
+ * 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.
+ */
+ public static final String ADDRESS_TRANSLATOR_DEFAULT_ADDRESS =
+ "advanced.address-translator.default-address";
+
+ /**
+ * Whether to resolve the addresses on initialization (if true) or on each
node (re-)connection
+ * (if false). Defaults to false.
+ */
+ public static final String ADDRESS_TRANSLATOR_RESOLVE_ADDRESSES =
+ "advanced.address-translator.resolve-addresses";
+
+ 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;
+ }
+ };
+
+ public static DriverOption ADDRESS_TRANSLATOR_RESOLVE_ADDRESSES_OPTION =
+ new DriverOption() {
+ @NonNull
+ @Override
+ public String getPath() {
+ return ADDRESS_TRANSLATOR_RESOLVE_ADDRESSES;
+ }
+ };
+
+ private final List<SubnetAddress> subnetAddresses;
+ @SuppressWarnings("OptionalUsedAsFieldOrParameterType")
+ private final Optional<InetSocketAddress> defaultAddress;
+ private final String logPrefix;
+
+ public SubnetAddressTranslator(@NonNull DriverContext context) {
+ logPrefix = context.getSessionName();
+ boolean resolveAddresses =
+ context
+ .getConfig()
+ .getDefaultProfile()
+ .getBoolean(ADDRESS_TRANSLATOR_RESOLVE_ADDRESSES_OPTION, false);
+ 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 subnetCIDR = e.getKey().replaceAll("\"", "");
+ String address = e.getValue();
+ return new SubnetAddress(subnetCIDR, parseAddress(address,
resolveAddresses));
+ })
+ .collect(Collectors.toList());
+ this.defaultAddress =
+ Optional.ofNullable(
+ context
+ .getConfig()
+ .getDefaultProfile()
+ .getString(ADDRESS_TRANSLATOR_DEFAULT_ADDRESS_OPTION,
null))
+ .map(address -> parseAddress(address, resolveAddresses));
+
+ 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("[{}] Translated {} to {}", logPrefix, address,
translatedAddress);
+ return translatedAddress;
+ }
+
+ @Override
+ public void close() {}
+
+ @Nullable
+ private InetSocketAddress parseAddress(String address, boolean resolve) {
+ try {
+ InetSocketAddress parsedAddress = AddressUtils.extract(address,
resolve).iterator().next();
+ LOG.debug("[{}] Parsed {} to {}", logPrefix, address, parsedAddress);
+ return parsedAddress;
+ } catch (RuntimeException e) {
+ throw new IllegalArgumentException(
+ String.format("Invalid address %s (%s)", address, e.getMessage()));
Review Comment:
Another exception handling nit - could you attach e as the cause here?
##########
core/src/main/java/com/datastax/oss/driver/internal/core/ContactPoints.java:
##########
@@ -41,7 +38,22 @@ public static Set<EndPoint> merge(
Set<EndPoint> result = Sets.newHashSet(programmaticContactPoints);
for (String spec : configContactPoints) {
- for (InetSocketAddress address : extract(spec, resolve)) {
+
+ Set<InetSocketAddress> addresses = Collections.emptySet();
+ try {
+ addresses = AddressUtils.extract(spec, resolve);
+ } catch (RuntimeException e) {
+ LOG.warn("Ignoring invalid contact point {} ({})", spec,
e.getMessage());
Review Comment:
Minor nit, could you include the entire exception here, rather than just the
message? Stacktrace could be helpful for debugging.
##########
core/src/main/java/com/datastax/oss/driver/internal/core/util/AddressUtils.java:
##########
@@ -0,0 +1,59 @@
+/*
+ * 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.util;
+
+import com.datastax.oss.driver.shaded.guava.common.collect.ImmutableSet;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.UnknownHostException;
+import java.util.HashSet;
+import java.util.Set;
+
+public class AddressUtils {
+
+ public static Set<InetSocketAddress> extract(String address, boolean
resolve) {
+ int separator = address.lastIndexOf(':');
+ if (separator < 0) {
+ throw new IllegalArgumentException("expecting format host:port");
+ }
+
+ String host = address.substring(0, separator);
+ String portString = address.substring(separator + 1);
+ int port;
+ try {
+ port = Integer.parseInt(portString);
+ } catch (NumberFormatException e) {
+ throw new IllegalArgumentException("expecting port to be a number, got "
+ portString, e);
+ }
+ if (!resolve) {
+ return ImmutableSet.of(InetSocketAddress.createUnresolved(host, port));
+ } else {
+ InetAddress[] inetAddresses;
+ try {
+ inetAddresses = InetAddress.getAllByName(host);
+ } catch (UnknownHostException e) {
+ throw new RuntimeException("unknown host " + host, e);
Review Comment:
Really minor nit, but could make the UnknownHostException a cause for the
RuntimeException here, without the custom message, the stacktrace should be
clear
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