Does Go Lack Onboard DNS Caching?

Does Go Lack Onboard DNS Caching?

Despite being a notable aspect of resource-efficient operation in web crawling, Go currently lacks native DNS lookup caching. This raises the question of whether the underlying operating system includes any caching facilities that Go can leverage.

Examining Potential Alternatives

While Go does not provide built-in caching, the underlying OS may offer options:

• Debian/Ubuntu/Linux: No explicit DNS caching mechanism
• Windows: Maintains a HOSTS file for local DNS resolution
• Darwin/OSX: Supports mDNS responder and caching

Exploring Third-Party Solutions

To compensate for the lack of native caching in Go, consider external packages like dnscache. This solution allows for easy implementation of DNS caching, as demonstrated by the code snippet in the readme:

http.DefaultClient.Transport = &http.Transport {
MaxIdleConnsPerHost: 64,
Dial: func(network string, address string) (net.Conn, error) {
separator := strings.LastIndex(address, ":")
ip, _ := dnscache.FetchString(address[:separator])
return net.Dial("tcp", ip + address[separator:])
},
}

Implementing this code enables caching for all HTTP requests made through functions such as http.Get.

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