Disable options.dnsCache by default

Author: szmarczak

readme.md

@@ -481,10 +481,13 @@ Default: `false`
 
 ###### dnsCache
 
-Type: `object | false`\
-Default: `new CacheableLookup()`
+Type: `CacheableLookup | false`\
+Default: `false`
+
+An instance of [`CacheableLookup`](https://github.com/szmarczak/cacheable-lookup) used for making DNS lookups. Useful when making lots of requests to different *public* hostnames.
 
-An instance of [`CacheableLookup`](https://github.com/szmarczak/cacheable-lookup) used for making DNS lookups.
+**Note:** This should stay disabled when making requests to internal hostnames such as `localhost`, `database.local` etc.\
+`CacheableLookup` uses `dns.resolver4(..)` and `dns.resolver6(...)` under the hood and fall backs to `dns.lookup(...)` when the first two fail, which may lead to additional delay.
 
 ###### request
 

source/core/index.ts

@@ -594,6 +594,10 @@ export default class Request extends Duplex implements RequestEvents<Request> {
 			options.cache = undefined;
 		}
 
+		if (options.dnsCache === false) {
+			options.cache = undefined;
+		}
+
 		// Nice type assertions
 		assert.any([is.string, is.undefined], options.method);
 		assert.any([is.object, is.undefined], options.headers);

source/index.ts

@@ -1,5 +1,4 @@
 import {URL} from 'url';
-import CacheableLookup from 'cacheable-lookup';
 import {Response, Options} from './as-promise';
 import create, {defaultHandler, InstanceDefaults} from './create';
 
@@ -54,7 +53,7 @@ const defaults: InstanceDefaults = {
 			afterResponse: []
 		},
 		cache: undefined,
-		dnsCache: new CacheableLookup(),
+		dnsCache: undefined,
 		decompress: true,
 		throwHttpErrors: true,
 		followRedirect: true,