feat: add dns cache #2440

index.js

@@ -165,3 +165,6 @@ module.exports.MockClient = MockClient
 module.exports.MockPool = MockPool
 module.exports.MockAgent = MockAgent
 module.exports.mockErrors = mockErrors
+
+const DNSResolver = require('./lib/core/dns-resolver')
+module.exports.DNSResolver = DNSResolver

lib/agent.js

@@ -7,6 +7,7 @@ const Pool = require('./pool')
 const Client = require('./client')
 const util = require('./core/util')
 const createRedirectInterceptor = require('./interceptor/redirectInterceptor')
+const DNSResolver = require('./core/dns-resolver')
 
 const kOnConnect = Symbol('onConnect')
 const kOnDisconnect = Symbol('onDisconnect')
@@ -22,6 +23,14 @@ function defaultFactory (origin, opts) {
     : new Pool(origin, opts)
 }
 
+function getDnsResolver (options = {}) {
+  if (options.DNSResolver instanceof DNSResolver) {
+    return options.DNSResolver
+  }
+
+  return options?.dnsResolver?.disable ? undefined : new DNSResolver(options?.dnsResolver)
+}
+
 class Agent extends DispatcherBase {
   constructor ({ factory = defaultFactory, maxRedirections = 0, connect, ...options } = {}) {
     super()
@@ -50,6 +59,7 @@ class Agent extends DispatcherBase {
     this[kOptions].interceptors = options.interceptors
       ? { ...options.interceptors }
       : undefined
+    this[kOptions].dnsResolver = getDnsResolver(options)
     this[kMaxRedirections] = maxRedirections
     this[kFactory] = factory
     this[kClients] = new Map()