CASSNODEJS-16: Use system resolver for contact points

[finalchild]

Summary

• Resolve contact-point hostnames through the operating system resolver with dns.lookup(name, { all: true }).
• Preserve every IPv4 and IPv6 result and the configured contact-point port.

Motivation

The current implementation uses dns.resolve4() and dns.resolve6(), which query DNS through c-ares rather than following the operating system's complete name-resolution policy. This can bypass hosts files, NSS, Windows name-resolution policy, VPN and split-DNS configuration, and resolvers such as Tailscale MagicDNS.

The direct-DNS implementation was introduced in #147 when this driver supported Node.js 0.10. The driver now requires Node.js 20 or newer, where dns.lookup() supports { all: true }, so using the system resolver no longer requires sacrificing multi-address discovery.

This also follows the approach used by other official Cassandra drivers:

• Java resolves all addresses with InetAddress.getAllByName() in AddressUtils.extract().
• Python resolves contact points with socket.getaddrinfo(..., AF_UNSPEC, SOCK_STREAM).
• C++ uses uv_getaddrinfo() with AF_UNSPEC and iterates every result.

This interacted badly with search domain with Tailscale. localhost resolved to localhost.search.domain instead. Using the OS resolver avoids this issue and is more idiomatic.

On Windows, when using resolve4/6, localhost does not return the loopback adddress. On typical Linux, resolve4/6 queries systemd-resolved which returns loopback address.

References

• Jira: https://issues.apache.org/jira/browse/CASSNODEJS-16
• Original resolver PR: Use all IPv4 and IPv6 addresses from dns records #147
• Node.js DNS documentation: https://nodejs.org/api/dns.html#dnslookuphostname-options-callback
• Java driver: https://github.com/apache/cassandra-java-driver/blob/trunk/core/src/main/java/com/datastax/oss/driver/internal/core/util/AddressUtils.java
• Python driver: https://github.com/apache/cassandra-python-driver/blob/trunk/cassandra/cluster.py
• C++ driver: https://github.com/apache/cassandra-cpp-driver/blob/trunk/src/resolver.hpp

[jorgebay]

Looks good to me 👍

[Copilot]

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Copilot review overview

2 open findings

• dns.lookup() result order can be affected by Node's default result order (e.g., via… · New
• When the system resolver returns an empty array, addresses.map(...) allocates a new empty array… · New

What changed in this PR

Updates the control connection hostname resolution to use the OS/system resolver via dns.lookup(..., { all: true }), ensuring contact points honor platform name-resolution policies and return all IPv4/IPv6 addresses.

Changes:

• Replaced dns.resolve4()/dns.resolve6() logic with a single dns.lookup(name, { all: true }) call in _resolveAll().
• Updated unit tests to stub/assert dns.lookup() behavior (including multi-address results and error/empty cases).

File	Description
lib/​control-connection.js	Switches _resolveAll() to use OS resolver (dns.lookup with { all: true }) and simplifies error handling.
test/​unit/​control-connection-tests.js	Adjusts mocks/assertions to validate dns.lookup usage and new error/empty-result behaviors.

🧠 Review effort: Lite

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[SiyaoIsHiding]

Looks good to me, thank you very much for the contribution!