DNS Cache

DNS Cache for http client

API

New

create a dns cache instance

• ttl cache's ttl seconds

onStats := func(h string, d time.Duration, _ []string) {
  fmt.Println(d)
}
dc := dnscache.New(
  time.Minute,
  dnscache.PolicyOption(dnscache.PolicyRandom),
  dnscache.StaleOption(time.Minute),
  dnscache.OnStatsOption(onStats),
  dnscache.NetworkOption(dnscache.NetworkIPV4),
)

Lookup

lookup ip address for host

• host host name

dc := dnscache.New(time.Minute)
ipAddrs, err := dc.Lookup(context.Background(), "www.baidu.com")

LookupWithCache

lookup ip address for host, it will use the cache first.

• host host name

dc := dnscache.New(time.Minute)
ipAddrs, err := dc.LookupWithCache(context.Background(), "www.baidu.com")

GetDialContext

get dial context function for http client

dc := dnscache.New(time.Minute)
http.DefaultClient.Transport = &http.Transport{
  DialContext: dc.GetDialContext(),
}
resp, err := http.Get("https://www.baidu.com/")

Set

set the dns cache, if the CreatedAt is less than 0, it will never be expired.

dc := dnscache.New(time.Minute)
dc.Set("www.baidu.com", IPCache{
  CreatedAt: time.Now().Unix(),
  IPAddrs: []net.IP{
    net.ParseIP("1.1.1.1"),
  },
})

Get

get the dns cache

dc := dnscache.New(time.Minute)
host := "www.baidu.com"
dc.Set(host, IPCache{
  CreatedAt: time.Now().Unix(),
  IPAddrs: []net.IP{
    net.ParseIP("1.1.1.1"),
  },
})
cache, ok := dc.Get(host)