Go会缓存DNS查找吗？ [英] Does Go cache DNS lookups?

问题描述

我正在构建一个测试搜寻器，想知道Go（golang）是否缓存DNS查询。我没有在 dnsclient 中看到有关缓存的任何信息。添加到任何搜寻器以防止大量额外的DNS查询似乎很重要。

I am building a test crawler and wanted to know if Go (golang) caches DNS queries. I don't see anything about caching in the dnsclient. This seems like an important thing to add to any crawler to prevent lots of extra DNS queries.

Go（1.4+）是否缓存DNS查找？

如果没有， debian / ubuntu / linux，windows或darwin / OSX可以在Go上进行网络级缓存吗？

If not, does debian/ubuntu/linux, windows, or darwin/OSX do any caching at the network level Go benefits from?

推荐答案

您的问题的答案是否定的。 std lib解析器中没有内置的dns缓存。有帮助吗？也许在某些情况下。我们的组织在每个服务器上运行本地dns缓存，并将resolv.conf指向该服务器。因此，使用该语言进行缓存不一定会对我们有太大帮助。

The answer to your question is no. There is no built-in dns caching in the std lib resolver. Would it be helpful? Maybe in some cases. Our org runs a local dns cache on each server and points resolv.conf there. So it wouldn't necessarily help us much to have caching in the language.

有些解决方案可以为您提供帮助。 此软件包似乎有一个很好的解决方案。从他们的自述文件中，您甚至可以执行以下操作：

There are some solutions that could help you. This package seems to have a pretty good solution. From the snippet in their readme you could even do:

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:])
  },
}

为 http.Get 和朋友的所有http请求启用它

To enable it for all http requests from http.Get and friends.

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