Files
cloudron-box/src/waitfordns.js
2016-11-29 14:47:32 +01:00

99 lines
3.8 KiB
JavaScript

'use strict';
exports = module.exports = waitForDns;
var assert = require('assert'),
async = require('async'),
debug = require('debug')('box:src/waitfordns'),
dns = require('native-dns'),
tld = require('tldjs');
// the first arg to callback is not an error argument; this is required for async.every
function isChangeSynced(domain, value, type, nameserver, callback) {
assert.strictEqual(typeof domain, 'string');
assert.strictEqual(typeof value, 'string');
assert.strictEqual(typeof type, 'string');
assert.strictEqual(typeof nameserver, 'string');
assert.strictEqual(typeof callback, 'function');
// ns records cannot have cname
dns.resolve4(nameserver, function (error, nsIps) {
if (error || !nsIps || nsIps.length === 0) {
debug('nameserver %s does not resolve. assuming it stays bad.', nameserver); // it's fine if one or more ns are dead
return callback(true);
}
async.every(nsIps, function (nsIp, iteratorCallback) {
var req = dns.Request({
question: dns.Question({ name: domain, type: type }),
server: { address: nsIp },
timeout: 5000
});
req.on('timeout', function () {
debug('nameserver %s (%s) timed out when trying to resolve %s', nameserver, nsIp, domain);
return iteratorCallback(true); // should be ok if dns server is down
});
req.on('message', function (error, message) {
if (error) {
debug('nameserver %s (%s) returned error trying to resolve %s: %s', nameserver, nsIp, domain, error);
return iteratorCallback(false);
}
var answer = message.answer;
if (!answer || answer.length === 0) {
debug('bad answer from nameserver %s (%s) resolving %s (%s): %j', nameserver, nsIp, domain, type, message);
return iteratorCallback(false);
}
debug('isChangeSynced: ns: %s (%s), name:%s Actual:%j Expecting:%s', nameserver, nsIp, domain, answer, value);
var match = answer.some(function (a) {
return ((type === 'A' && a.address === value) || (type === 'CNAME' && a.data === value));
});
if (match) return iteratorCallback(true); // done!
iteratorCallback(false);
});
req.send();
}, callback);
});
}
// check if IP change has propagated to every nameserver
function waitForDns(domain, value, type, options, callback) {
assert.strictEqual(typeof domain, 'string');
assert.strictEqual(typeof value, 'string');
assert(type === 'A' || type === 'CNAME');
assert(options && typeof options === 'object'); // { interval: 5000, times: 50000 }
assert.strictEqual(typeof callback, 'function');
var zoneName = tld.getDomain(domain);
debug('waitForIp: domain %s to be %s in zone %s.', domain, value, zoneName);
var attempt = 1;
async.retry(options, function (retryCallback) {
debug('waitForDNS: %s attempt %s.', domain, attempt++);
dns.resolveNs(zoneName, function (error, nameservers) {
if (error || !nameservers) return retryCallback(error || new Error('Unable to get nameservers'));
async.every(nameservers, isChangeSynced.bind(null, domain, value, type), function (synced) {
debug('waitForIp: %s %s ns: %j', domain, synced ? 'done' : 'not done', nameservers);
retryCallback(synced ? null : new Error('ETRYAGAIN'));
});
});
}, function retryDone(error) {
if (error) return callback(error);
debug('waitForDNS: %s done.', domain);
callback(null);
});
}