Does Go (golang) Include Built-in DNS Caching?

DNS Caching in Go

In the development of a test crawler, a common inquiry arises: does Go (golang) implement caching mechanisms for DNS queries?

Upon examining the dnsclient package, no explicit mention of caching is discernible. However, this functionality is often crucial for crawler optimization, minimizing extra DNS queries.

Answer:

The default implementation of Go (1.4 ) does not include built-in DNS caching.

Alternative Caching Mechanisms:

• Local DNS Cache: Debian, Ubuntu/Linux, Windows, and Darwin/OSX provide the option to configure a local DNS cache, which can potentially benefit Go's DNS operations.
• Third-Party Packages: A range of third-party packages are available to implement caching for Go's DNS resolver, such as github.com/miekg/dnscache.
• HTTP Client Integration: With the dnscache package, it is possible to leverage its functionality within the context of HTTP requests using custom transport settings.

Example:

<code class="go">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:])
  },
}</code>

The above is the detailed content of Does Go (golang) Include Built-in DNS Caching?. For more information, please follow other related articles on the PHP Chinese website!