Load zone from master on startup

config.json.defaults

@@ -3,5 +3,10 @@
 	"knotLocation": "/usr/sbin/knotc",
 	"dbHost": "localhost",
 	"listenAddress": "127.0.0.1",
-	"listenPort": 3000
+	"listenPort": 3000,
+	"master": {
+		"address": "https://dyndns.example.com",
+		"myId": "ns-test",
+		"key": "verysecret"
+	}
 }
\ No newline at end of file

database.js

@@ -48,7 +48,28 @@ function updateDomain(domain, token, ip) {
 		Domain.updateOne({ token: token }, { name: domain, token: token, ip: ip })
 			.catch((err) => reject())
 			.then((d) => resolve());
-	})
+	});
+}
+
+function insertDomain(domain, token, ip) {
+	return new Promise((resolve, reject) => {
+		const record = new Domain({
+			name: domain,
+			token: token,
+			ip: ip
+		});
+		record.save()
+			.catch((err) => reject(err))
+			.then(() => resolve());
+	});
+}
+
+function clearDomains() {
+	return new Promise((resolve, reject) => {
+		Domain.deleteMany({})
+			.catch(err => reject(err))
+			.then(() => resolve());
+	});
 }
 
 module.exports = {
@@ -56,5 +77,7 @@ module.exports = {
 	domainExists: domainExists,
 	registerDomain: registerDomain,
 	getDomain: getDomain,
-	updateDomain: updateDomain
+	updateDomain: updateDomain,
+	insertDomain: insertDomain,
+	clearDomains: clearDomains
 }
\ No newline at end of file

index.js

+const https = require('https');
 const express = require('express');
+
+// Initialize
+// --------------------------------------------------------
+
 const app = express();
 
 const config = require('./config');
@@ -7,9 +12,65 @@ config.init();
 const db = require('./database');
 db.init();
 
+// Sync records from master
+// --------------------------------------------------------
+
+console.log("Syncing records from " + config.config().master.address + "/ ...");
+
+https.get(config.config().master.address + '/dyndns-list?id=' + config.config().master.myId + '&key=' + config.config().master.key, (res) => {
+	if (res.statusCode > 299) {
+		process.exit(2);
+		return;
+	}
+
+	let response = '';
+
+	res.on('data', (chunk) => response += chunk);
+
+	res.on('end', () => {
+		db.clearDomains().then(() => {
+			knotdns.clearZone().then(() => {
+				console.log("Purged existing domains");
+				try {
+					records = JSON.parse(response);
+
+					async function loadRecords(records) {
+						for (const r of records) {
+							const domain = r.domain.split(".")[0];
+							const token = r.token;
+							const ip = r.ip;
+
+							if (ip == "null") {
+								await db.registerDomain(domain, token);
+								console.log("Registering record without IP: " + domain);
+							} else {
+								await db.insertDomain(domain, token, ip);
+								await knotdns.updateRecord(domain, ip);
+								console.log("Registering domain " + domain + " to " + ip);
+							}
+						};
+					}
+					loadRecords(records);
+				} catch (error) {
+					console.error("Error parsing records from master: ", error);
+					process.exit(1);
+				}
+			})
+		})
+	});
+}).on('error', (error) => {
+	console.error("Could not sync records from master: ", error);
+	process.exit(1);
+});
+
+// Register and serve endpoints
+// --------------------------------------------------------
+
 const registerMW = require('./middleware/registerMW');
 const replyMW = require('./middleware/replyMW');
 const updateMW = require('./middleware/updateMW');
+const { error } = require('console');
+const knotdns = require('./knotdns');
 
 // register a new dyndns record
 app.get('/register', registerMW(), replyMW());

knotdns.js

@@ -3,6 +3,37 @@ const exec = util.promisify(require('child_process').exec);
 
 const config = require('./config');
 
+async function clearZone() {
+
+	const { stdout, stderr } = await exec(config.config().knotLocation + " zone-read " + config.config().higherLevelDomain);
+	const domains = stdout
+		.split('\n')
+		.filter(line => line.includes(' 60 A '))       //filter for A records
+		.map(line => line.match('\] (.*) 60 A ')[1])   // regex match for full domains
+		.map(domain => domain.split('.')[0]);          // cut subdomain
+
+	await exec(config.config().knotLocation + " zone-begin " + config.config().higherLevelDomain);
+	for (domain of domains) {
+		await exec(config.config().knotLocation + " zone-unset " + config.config().higherLevelDomain + " " + domain);
+	}
+	await exec(config.config().knotLocation + " zone-commit " + config.config().higherLevelDomain);
+}
+
+async function insertRecord(domain, ip) {
+	try {
+		await exec(config.config().knotLocation + " zone-begin " + config.config().higherLevelDomain);
+		await exec(config.config().knotLocation + " zone-set " + config.config().higherLevelDomain + " " + domain + " 60 A " + ip);
+		await exec(config.config().knotLocation + " zone-commit " + config.config().higherLevelDomain);
+	} catch (error) {
+		try {
+			await exec(config.config().knotLocation + " zone-abort " + config.config().higherLevelDomain);
+			console.log("Problem with manipulating DNS zone " + config.config().higherLevelDomain + ". Aborted transaction. " + error);
+		} catch {
+			console.log("Problem with manipulating DNS zone " + config.config().higherLevelDomain + ". Could not even abort transaction. " + error);
+		}
+	}
+}
+
 async function updateRecord(domain, ip) {
 	try {
 		await exec(config.config().knotLocation + " zone-begin " + config.config().higherLevelDomain);
@@ -23,6 +54,10 @@ async function updateRecord(domain, ip) {
 	}
 }
 
+
+
 module.exports = {
-	updateRecord: updateRecord
+	updateRecord: updateRecord,
+	insertRecord: insertRecord,
+	clearZone: clearZone
 }
\ No newline at end of file