dns: add a cancel() method to the promise Resolver

PR-URL: #33099 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Juan José Arboleda <[email protected]> Reviewed-By: Antoine du Hamel <[email protected]>

Author: szmarczak

doc/api/dns.md

@@ -730,6 +730,14 @@ The following methods from the `dnsPromises` API are available:
 *[`resolver.reverse()`][`dnsPromises.reverse()`]
 *[`resolver.setServers()`][`dnsPromises.setServers()`]
 
+### `resolver.cancel()`
+<!-- YAML
+added: REPLACEME
+-->
+
+Cancel all outstanding DNS queries made by this resolver. The corresponding
+promises will be rejected with an error with code `ECANCELLED`.
+
 ### `dnsPromises.getServers()`
 <!-- YAML
 added: v10.6.0

lib/internal/dns/promises.js

@@ -217,6 +217,7 @@ class Resolver{
 
 Resolver.prototype.getServers=CallbackResolver.prototype.getServers;
 Resolver.prototype.setServers=CallbackResolver.prototype.setServers;
+Resolver.prototype.cancel=CallbackResolver.prototype.cancel;
 Resolver.prototype.setLocalAddress=CallbackResolver.prototype.setLocalAddress;
 Resolver.prototype.resolveAny=resolveMap.ANY=resolver('queryAny');
 Resolver.prototype.resolve4=resolveMap.A=resolver('queryA');

test/parallel/test-dns-channel-cancel-promise.js

@@ -0,0 +1,65 @@
+'use strict';
+constcommon=require('../common');
+const{promises: dnsPromises}=require('dns');
+constassert=require('assert');
+constdgram=require('dgram');
+
+constserver=dgram.createSocket('udp4');
+constresolver=newdnsPromises.Resolver();
+
+constaddMessageListener=()=>{
+server.removeAllListeners('message');
+
+server.once('message',()=>{
+server.once('message',common.mustNotCall);
+
+resolver.cancel();
+});
+};
+
+server.bind(0,common.mustCall(async()=>{
+resolver.setServers([`127.0.0.1:${server.address().port}`]);
+
+addMessageListener();
+
+// Single promise
+{
+consthostname='example0.org';
+
+awaitassert.rejects(
+resolver.resolve4(hostname),
+{
+code: 'ECANCELLED',
+syscall: 'queryA',
+ hostname
+}
+);
+}
+
+addMessageListener();
+
+// Multiple promises
+{
+constassertions=[];
+constassertionCount=10;
+
+for(leti=1;i<=assertionCount;i++){
+consthostname=`example${i}.org`;
+
+assertions.push(
+assert.rejects(
+resolver.resolve4(hostname),
+{
+code: 'ECANCELLED',
+syscall: 'queryA',
+hostname: hostname
+}
+)
+);
+}
+
+awaitPromise.all(assertions);
+}
+
+server.close();
+}));

test/parallel/test-dns-channel-cancel.js

@@ -1,28 +1,51 @@
 'use strict';
 constcommon=require('../common');
-constdnstools=require('../common/dns');
 const{ Resolver }=require('dns');
 constassert=require('assert');
 constdgram=require('dgram');
 
 constserver=dgram.createSocket('udp4');
 constresolver=newResolver();
 
-server.bind(0,common.mustCall(()=>{
+constdesiredQueries=11;
+letfinishedQueries=0;
+
+constaddMessageListener=()=>{
+server.removeAllListeners('message');
+
+server.once('message',()=>{
+server.once('message',common.mustNotCall);
+
+resolver.cancel();
+});
+};
+
+server.bind(0,common.mustCall(async()=>{
 resolver.setServers([`127.0.0.1:${server.address().port}`]);
-resolver.resolve4('example.org',common.mustCall((err,res)=>{
+
+constcallback=common.mustCall((err,res)=>{
 assert.strictEqual(err.code,'ECANCELLED');
 assert.strictEqual(err.syscall,'queryA');
-assert.strictEqual(err.hostname,'example.org');
-server.close();
-}));
-}));
+assert.strictEqual(err.hostname,`example${finishedQueries}.org`);
+
+finishedQueries++;
+if(finishedQueries===desiredQueries){
+server.close();
+}
+},desiredQueries);
+
+constnext=(...args)=>{
+callback(...args);
+
+addMessageListener();
 
-server.on('message',common.mustCall((msg,{ address, port })=>{
-constparsed=dnstools.parseDNSPacket(msg);
-constdomain=parsed.questions[0].domain;
-assert.strictEqual(domain,'example.org');
+// Multiple queries
+for(leti=1;i<desiredQueries;i++){
+resolver.resolve4(`example${i}.org`,callback);
+}
+};
 
-// Do not send a reply.
-resolver.cancel();
+// Single query
+addMessageListener();
+resolver.resolve4('example0.org',next);
 }));