feat(dns): add configurable timeout for DNS monitor (louislam#6990)

Co-authored-by: Maks Pikov <mixelburg@users.noreply.github.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Frank Elsinga <frank@elsinga.de>

Author: 3 people

server/monitor-types/dns.js

@@ -24,7 +24,13 @@ class DnsMonitorType extends MonitorType {
         let dnsMessage = "";
 
         const resolverServers = await this.resolveDnsResolverServers(monitor.dns_resolve_server);
-        let dnsRes = await this.dnsResolve(monitor.hostname, resolverServers, monitor.port, monitor.dns_resolve_type);
+        let dnsRes = await this.dnsResolve(
+            monitor.hostname,
+            resolverServers,
+            monitor.port,
+            monitor.dns_resolve_type,
+            monitor.timeout != null ? monitor.timeout * 1000 : 5000
+        );
         heartbeat.ping = dayjs().valueOf() - startTime;
 
         const conditions = ConditionExpressionGroup.fromMonitor(monitor);
@@ -169,10 +175,11 @@ class DnsMonitorType extends MonitorType {
      * @param {string[]} resolverServer Array of DNS server IP addresses to use
      * @param {string} resolverPort Port the DNS server is listening on
      * @param {string} rrtype The type of record to request
+     * @param {number} timeout Timeout in milliseconds for the DNS query (defaults to c-ares default of 5000ms)
      * @returns {Promise<(string[] | object[] | object)>} DNS response
      */
-    async dnsResolve(hostname, resolverServer, resolverPort, rrtype) {
-        const resolver = new Resolver();
+    async dnsResolve(hostname, resolverServer, resolverPort, rrtype, timeout = 5000) {
+        const resolver = new Resolver({ timeout });
         resolver.setServers(resolverServer.map((server) => `[${server}]:${resolverPort}`));
         if (rrtype === "PTR") {
             return await resolver.reverse(hostname);

src/pages/EditMonitor.vue

@@ -1430,6 +1430,7 @@
                             <!-- Timeout: HTTP / JSON query / Keyword / Ping / RabbitMQ / SNMP / Websocket Upgrade only -->
                             <div
                                 v-if="
+                                    monitor.type === 'dns' ||
                                     monitor.type === 'http' ||
                                     monitor.type === 'json-query' ||
                                     monitor.type === 'keyword' ||