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CASSNODEJS-16: Use system resolver for contact points #479

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Merged
SiyaoIsHiding merged 1 commit into from
Oct 15, 2026
Merged

CASSNODEJS-16: Use system resolver for contact points #479

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33 changes: 7 additions & 26 deletions lib/control-connection.js
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Original file line number Diff line number Diff line change
Expand Up @@ -895,40 +895,21 @@ class ControlConnection extends events.EventEmitter {
}

/**
* Uses the DNS protocol to resolve a IPv4 and IPv6 addresses (A and AAAA records) for the hostname.
* Uses the operating system resolver to resolve all IPv4 and IPv6 addresses for the hostname.
* It returns an Array of addresses that can be empty and logs the error.
* @private
* @param name
*/
async _resolveAll(name) {
const addresses = [];
const resolve4 = util.promisify(dns.resolve4);
const resolve6 = util.promisify(dns.resolve6);
const lookup = util.promisify(dns.lookup);

// Ignore errors for resolve calls
const ipv4Promise = resolve4(name).catch(() => {}).then(r => r || utils.emptyArray);
const ipv6Promise = resolve6(name).catch(() => {}).then(r => r || utils.emptyArray);

let arr;
arr = await ipv4Promise;
arr.forEach(address => addresses.push({address, isIPv6: false}));

arr = await ipv6Promise;
arr.forEach(address => addresses.push({address, isIPv6: true}));

if (addresses.length === 0) {
// In case dns.resolve*() methods don't yield a valid address for the host name
// Use system call getaddrinfo() that might resolve according to host system definitions
try {
arr = await lookup(name, { all: true });
arr.forEach(({address, family}) => addresses.push({address, isIPv6: family === 6}));
} catch (err) {
this.log('error', `Host with name ${name} could not be resolved`, err);
}
try {
const addresses = await lookup(name, { all: true });
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return addresses.map(({address, family}) => ({address, isIPv6: family === 6}));
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} catch (err) {
this.log('error', `Host with name ${name} could not be resolved`, err);
return utils.emptyArray;
}

return addresses;
}

/**
Expand Down
99 changes: 34 additions & 65 deletions test/unit/control-connection-tests.js
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Original file line number Diff line number Diff line change
Expand Up @@ -81,14 +81,12 @@ describe('ControlConnection', function () {

it('should resolve IPv4 and IPv6 addresses, default host (localhost) and port', () => {
const ControlConnectionMock = proxyquire('../../lib/control-connection', { dns: {
resolve4: function (name, cb) {
cb(null, ifLocalhost(name, ['127.0.0.1']));
},
resolve6: function (name, cb) {
cb(null, ifLocalhost(name, ['::1']));
},
lookup: function () {
throw new Error('dns.lookup() should not be used');
lookup: function (name, options, cb) {
assert.deepStrictEqual(options, { all: true });
cb(null, ifLocalhost(name, [
{ address: '127.0.0.1', family: 4 },
{ address: '::1', family: 6 }
]));
}
}});

Expand All @@ -99,14 +97,12 @@ describe('ControlConnection', function () {

it('should resolve IPv4 and IPv6 addresses with non default port', () => {
const ControlConnectionMock = proxyquire('../../lib/control-connection', { dns: {
resolve4: function (name, cb) {
cb(null, ifLocalhost(name, ['127.0.0.1']));
},
resolve6: function (name, cb) {
cb(null, ifLocalhost(name, ['::1']));
},
lookup: function () {
throw new Error('dns.lookup() should not be used');
lookup: function (name, options, cb) {
assert.deepStrictEqual(options, { all: true });
cb(null, ifLocalhost(name, [
{ address: '127.0.0.1', family: 4 },
{ address: '::1', family: 6 }
]));
}
}});

Expand All @@ -116,16 +112,23 @@ describe('ControlConnection', function () {
'localhost:9999');
});

it('should resolve all IPv4 and IPv6 addresses provided by dns.resolve()', () => {
it('should resolve all IPv4 and IPv6 addresses using the operating system resolver', () => {
const ControlConnectionMock = proxyquire('../../lib/control-connection', { dns: {
resolve4: function (name, cb) {
cb(null, ['1', '2']);
resolve4: function () {
throw new Error('dns.resolve4() should not be used');
},
resolve6: function (name, cb) {
cb(null, ['10', '20']);
resolve6: function () {
throw new Error('dns.resolve6() should not be used');
},
lookup: function () {
throw new Error('dns.lookup() should not be used');
lookup: function (name, options, cb) {
assert.strictEqual(name, 'localhost');
assert.deepStrictEqual(options, { all: true });
cb(null, [
{ address: '1', family: 4 },
{ address: '2', family: 4 },
{ address: '10', family: 6 },
{ address: '20', family: 6 }
]);
}
}});

Expand All @@ -134,52 +137,24 @@ describe('ControlConnection', function () {
[ '1:9042', '2:9042', '[10]:9042', '[20]:9042' ]);
});

it('should ignore IPv4 or IPv6 resolution errors', function () {
it('should handle system resolver errors', function () {
const ControlConnectionMock = proxyquire('../../lib/control-connection', { dns: {
resolve4: function (name, cb) {
cb(null, ['1', '2']);
},
resolve6: function (name, cb) {
lookup: function (name, options, cb) {
cb(new Error('Test error'));
},
lookup: function () {
throw new Error('dns.lookup() should not be used');
}
}});

return testResolution(ControlConnectionMock, [ '1:9042', '2:9042']);
return testResolution(ControlConnectionMock, [], utils.emptyArray);
});

it('should use dns.lookup() as failover', () => {
it('should handle an empty system resolver result', () => {
const ControlConnectionMock = proxyquire('../../lib/control-connection', { dns: {
resolve4: function (name, cb) {
cb(new Error('Test error'));
},
resolve6: function (name, cb) {
cb(new Error('Test error'));
},
lookup: function (name, options, cb) {
cb(null, [{ address: '123', family: 4 }]);
}
}});

return testResolution(ControlConnectionMock, [ '123:9042' ]);
});

it('should use dns.lookup() when no address was resolved', () => {
const ControlConnectionMock = proxyquire('../../lib/control-connection', { dns: {
resolve4: function (name, cb) {
cb(null);
},
resolve6: function (name, cb) {
cb(null, []);
},
lookup: function (name, options, cb) {
cb(null, [{ address: '1234', family: 4 }]);
}
}});

return testResolution(ControlConnectionMock, [ '1234:9042' ]);
return testResolution(ControlConnectionMock, [], utils.emptyArray);
});

it('should continue iterating through the hosts when borrowing a connection fails',async () => {
Expand Down Expand Up @@ -284,19 +259,13 @@ describe('ControlConnection', function () {
const resolvedAddresses = ['1','2'];

const ControlConnectionMock = proxyquire('../../lib/control-connection', { dns: {
resolve4: function (name, cb) {
lookup: function (name, options, cb) {
if (dnsWorks) {
cb(null, resolvedAddresses);
cb(null, resolvedAddresses.map(address => ({ address, family: 4 })));
}
else {
cb(null, []);
}
},
resolve6: function (name, cb) {
throw new Error('IPv6 resolution errors should be ignored');
},
lookup: function () {
throw new Error('dns.lookup() should not be used');
}
}});
const cc = new ControlConnectionMock(
Expand Down Expand Up @@ -590,4 +559,4 @@ function getContext(options) {
return state.connection = getFakeConnection(endpoint, options.queryResults);
}
};
}
}
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