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chore: add domainName to InstanceConnectionInfo, part of DNS Config.
chore: Resolve DNS TXT record to instance name. Part of DNS Config.
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6 files changed

+444
-84
lines changed

6 files changed

+444
-84
lines changed

‎src/dns-lookup.ts‎

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@@ -0,0 +1,50 @@
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// Copyright 2025 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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import dns from 'node:dns';
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import {CloudSQLConnectorError} from './errors';
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export async function resolveTxtRecord(name: string): Promise<string> {
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return new Promise((resolve, reject) => {
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dns.resolveTxt(name, (err, addresses) => {
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if (err) {
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reject(
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new CloudSQLConnectorError({
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code: 'EDOMAINNAMELOOKUPERROR',
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message: 'Error looking up TXT record for domain ' + name,
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errors: [err],
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})
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);
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return;
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}
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if (!addresses || addresses.length === 0) {
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reject(
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new CloudSQLConnectorError({
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code: 'EDOMAINNAMELOOKUPFAILED',
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message: 'No records returned for domain ' + name,
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})
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);
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return;
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}
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// Each result may be split into multiple strings. Join the strings.
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const joinedAddresses = addresses.map(strs => strs.join(''));
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// Sort the results alphabetically for consistency,
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joinedAddresses.sort((a, b) => a.localeCompare(b));
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// Return the first result.
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resolve(joinedAddresses[0]);
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});
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});
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}

‎src/instance-connection-info.ts‎

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Original file line numberDiff line numberDiff line change
@@ -16,4 +16,5 @@ export interface InstanceConnectionInfo {
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projectId: string;
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regionId: string;
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instanceId: string;
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domainName: string | undefined;
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}

‎src/parse-instance-connection-name.ts‎

Lines changed: 63 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -14,32 +14,81 @@
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import {InstanceConnectionInfo} from './instance-connection-info';
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import {CloudSQLConnectorError} from './errors';
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import {resolveTxtRecord} from './dns-lookup';
1718

18-
export function parseInstanceConnectionName(
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instanceConnectionName: string | undefined
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): InstanceConnectionInfo {
21-
if (!instanceConnectionName) {
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export async function resolveInstanceName(
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name: string | undefined
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): Promise<InstanceConnectionInfo> {
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if (!name) {
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throw new CloudSQLConnectorError({
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message:
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'Missing instance connection name, expected: "PROJECT:REGION:INSTANCE"',
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code: 'ENOCONNECTIONNAME',
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});
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} else if (isInstanceConnectionName(name)) {
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return parseInstanceConnectionName(name);
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} else if (isValidDomainName(name)) {
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return await resolveDomainName(name);
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} else {
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throw new CloudSQLConnectorError({
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message:
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'Malformed Instance connection name, expected an instance connection name in the form "PROJECT:REGION:INSTANCE" or a valid domain name',
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code: 'EBADCONNECTIONNAME',
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});
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}
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}
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29-
const connectionNameRegex =
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/(?<projectId>[^:]+(:[^:]+)?):(?<regionId>[^:]+):(?<instanceId>[^:]+)/;
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const matches = String(instanceConnectionName).match(connectionNameRegex);
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if (!matches) {
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const connectionNameRegex =
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/^(?<projectId>[^:]+(:[^:]+)?):(?<regionId>[^:]+):(?<instanceId>[^:]+)$/;
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// The domain name pattern in accordance with RFC 1035, RFC 1123 and RFC 2181.
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// From Go Connector:
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const domainNameRegex =
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/^(?:[_a-z0-9](?:[_a-z0-9-]{0,61}[a-z0-9])?\.)+(?:[a-z](?:[a-z0-9-]{0,61}[a-z0-9])?)?$/;
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export function isValidDomainName(name: string): boolean {
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const matches = String(name).match(domainNameRegex);
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return Boolean(matches);
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}
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export function isInstanceConnectionName(name: string): boolean {
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const matches = String(name).match(connectionNameRegex);
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return Boolean(matches);
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}
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export async function resolveDomainName(
60+
name: string
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): Promise<InstanceConnectionInfo> {
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const icn = await resolveTxtRecord(name);
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if (!isInstanceConnectionName(icn)) {
3364
throw new CloudSQLConnectorError({
3465
message:
35-
'Malformed instance connection name provided: expected format ' +
36-
`of "PROJECT:REGION:INSTANCE", got ${instanceConnectionName}`,
37-
code: 'EBADCONNECTIONNAME',
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'Malformed instance connection name returned for domain ' +
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name +
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' : ' +
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icn,
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code: 'EBADDOMAINCONNECTIONNAME',
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});
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}
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74+
const info = parseInstanceConnectionName(icn);
75+
info.domainName = name;
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return info;
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}
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79+
export function parseInstanceConnectionName(
80+
instanceConnectionName: string | undefined
81+
): InstanceConnectionInfo {
82+
if (!instanceConnectionName) {
83+
throw new CloudSQLConnectorError({
84+
message:
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'Missing instance connection name, expected: "PROJECT:REGION:INSTANCE"',
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code: 'ENOCONNECTIONNAME',
3887
});
3988
}
4089

41-
const unmatchedItems = matches[0] !== matches.input;
42-
if (unmatchedItems || !matches.groups) {
90+
const matches = String(instanceConnectionName).match(connectionNameRegex);
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if (!matches || !matches.groups) {
4392
throw new CloudSQLConnectorError({
4493
message:
4594
'Malformed instance connection name provided: expected format ' +
@@ -52,5 +101,6 @@ export function parseInstanceConnectionName(
52101
projectId: matches.groups.projectId,
53102
regionId: matches.groups.regionId,
54103
instanceId: matches.groups.instanceId,
104+
domainName: undefined,
55105
};
56106
}

‎test/cloud-sql-instance.ts‎

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Original file line numberDiff line numberDiff line change
@@ -80,6 +80,7 @@ t.test('CloudSQLInstance', async t => {
8080
projectId: 'my-project',
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regionId: 'us-east1',
8282
instanceId: 'my-instance',
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domainName: undefined,
8384
},
8485
'should have expected connection info'
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);

‎test/dns-lookup.ts‎

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// Copyright 2025 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
4+
// you may not use this file except in compliance with the License.
5+
// You may obtain a copy of the License at
6+
//
7+
// https://www.apache.org/licenses/LICENSE-2.0
8+
//
9+
// Unless required by applicable law or agreed to in writing, software
10+
// distributed under the License is distributed on an "AS IS" BASIS,
11+
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12+
// See the License for the specific language governing permissions and
13+
// limitations under the License.
14+
15+
import t from 'tap';
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17+
t.test('lookup dns with mock responses', async t => {
18+
const {resolveTxtRecord} = t.mockRequire('../src/dns-lookup.ts', {
19+
'node:dns': {
20+
resolveTxt: (name, callback) => {
21+
switch (name) {
22+
case 'db.example.com':
23+
callback(null, [['my-project:region-1:instance']]);
24+
return;
25+
case 'multiple.example.com':
26+
callback(null, [
27+
['my-project:region-1:instance'],
28+
['another-project:region-1:instance'],
29+
]);
30+
return;
31+
case 'split.example.com':
32+
callback(null, [['my-project:', 'region-1:instance']]);
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return;
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case 'empty.example.com':
35+
callback(null, []);
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return;
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default:
38+
callback(new Error('not found'), null);
39+
return;
40+
}
41+
},
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},
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});
44+
45+
t.same(
46+
await resolveTxtRecord('db.example.com'),
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'my-project:region-1:instance',
48+
'valid domain name'
49+
);
50+
t.same(
51+
await resolveTxtRecord('split.example.com'),
52+
'my-project:region-1:instance',
53+
'valid domain name'
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);
55+
t.same(
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await resolveTxtRecord('multiple.example.com'),
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'another-project:region-1:instance',
58+
'valid domain name'
59+
);
60+
t.rejects(
61+
async () => await resolveTxtRecord('not-found.example.com'),
62+
{code: 'EDOMAINNAMELOOKUPERROR'},
63+
'should throw type error if an extra item is provided'
64+
);
65+
t.rejects(
66+
async () => await resolveTxtRecord('empty.example.com'),
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{code: 'EDOMAINNAMELOOKUPFAILED'},
68+
'should throw type error if an extra item is provided'
69+
);
70+
});
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72+
t.test('lookup dns with real responses', async t => {
73+
const {resolveTxtRecord} = t.mockRequire('../src/dns-lookup.ts', {});
74+
t.same(
75+
await resolveTxtRecord('valid-san-test.csqlconnectortest.com'),
76+
'cloud-sql-connector-testing:us-central1:postgres-customer-cas-test',
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'valid domain name'
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);
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});

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