headplane/app/server/headscale/config-dns.ts

128 lines
3.0 KiB
TypeScript

import { constants, access, readFile, writeFile } from 'node:fs/promises';
import { setTimeout } from 'node:timers/promises';
import log from '~/utils/log';
export interface DNSRecord {
type: 'A' | 'AAAA' | (string & {});
name: string;
value: string;
}
// This class is solely for DNS records that are out of tree in the main
// Headscale config file. If you are using dns.extra_records_path, it will
// be managed here and not in the main config file.
//
// All DNS insertions and deletions are handled by the main config manager,
// but are passed through to here if the extra file is being used.
export class HeadscaleDNSConfig {
private records: DNSRecord[];
private access: 'rw' | 'ro' | 'no';
private path?: string;
private writeLock = false;
constructor(
access: 'rw' | 'ro' | 'no',
records?: DNSRecord[],
path?: string,
) {
this.access = access;
this.records = records ?? [];
this.path = path;
}
readable() {
return this.access !== 'no';
}
writable() {
return this.access === 'rw';
}
get r() {
return this.records;
}
async patch(records: DNSRecord[]) {
if (!this.path || !this.readable() || !this.writable()) {
return;
}
this.records = records;
log.debug(
'config',
'Patching DNS records (%d -> %d)',
this.records.length,
records.length,
);
return this.write();
}
private async write() {
if (!this.path || !this.writable()) {
return;
}
while (this.writeLock) {
await setTimeout(100);
}
this.writeLock = true;
log.debug('config', 'Writing updated DNS configuration to %s', this.path);
const data = JSON.stringify(this.records, null, 4);
await writeFile(this.path, data);
this.writeLock = false;
}
}
export async function loadHeadscaleDNS(path?: string) {
if (!path) {
return;
}
log.debug('config', 'Loading Headscale DNS configuration file: %s', path);
const { w, r } = await validateConfigPath(path);
if (!r) {
return new HeadscaleDNSConfig('no');
}
const records = await loadConfigFile(path);
if (!records) {
return new HeadscaleDNSConfig('no');
}
return new HeadscaleDNSConfig(w ? 'rw' : 'ro', records, path);
}
async function validateConfigPath(path: string) {
try {
await access(path, constants.F_OK | constants.R_OK);
log.info('config', 'Found a valid Headscale DNS file at %s', path);
} catch (error) {
log.error('config', 'Unable to read a Headscale DNS file at %s', path);
log.error('config', '%s', error);
return { w: false, r: false };
}
try {
await access(path, constants.F_OK | constants.W_OK);
return { w: true, r: true };
} catch (error) {
log.warn('config', 'Headscale DNS file at %s is not writable', path);
return { w: false, r: true };
}
}
async function loadConfigFile(path: string) {
log.debug('config', 'Reading Headscale DNS file at %s', path);
try {
const data = await readFile(path, 'utf8');
const records = JSON.parse(data) as DNSRecord[];
return records;
} catch (e) {
log.error('config', 'Error reading Headscale DNS file at %s', path);
log.error('config', '%s', e);
return false;
}
}