今天，打算用golang的echo（https://github.com/labstack/echo）框架做一个demo，在按照其安装手册安装echo框架时，使用dep命令，如下：

dep ensure -add github.com/labstack/echo@^3.1

但是，虽然的git已经设置了代理，但是依然报错，如下：

Solving failure: unable to deduce repository and source type for “golang.org/x/crypto”: unable to read metadata: unable to fetch raw metadata: failed HTTP request to URL “http://golang.org/x/crypto?go-get=1”: Get http://golang.org/x/crypto?go-get=1: dial tcp 216.239.37.1:80: connectex: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

后面，终于在 https://github.com/golang/dep/issues/1322 中找到原因，解决方法如下：

if you have a proxy client put your proxy on in you cmd: run set http_proxy=ip:port before use dep ensure.example(windows):

set http_proxy=127.0.0.1:1235

set https_proxy=127.0.0.1:1235

it can visit golang.org to fix this issus

按照这个方式，终于解决了这个问题