lukad is correct, you could set the HTTP_PROXY environment variable, if you do this Go will use it by default.
Bash:
export HTTP_PROXY="http://proxyIp:proxyPort"
Go:
os.Setenv("HTTP_PROXY", "http://proxyIp:proxyPort")
You could also construct your own http.Client that MUST use a proxy regardless of the environment’s configuration:
proxyUrl, err := url.Parse("http://proxyIp:proxyPort")
myClient := &http.Client{Transport: &http.Transport{Proxy: http.ProxyURL(proxyUrl)}}
This is useful if you can not depend on the environment’s configuration, or do not want to modify it.
You could also modify the default transport used by the “net/http” package. This would affect your entire program (including the default HTTP client).
proxyUrl, err := url.Parse("http://proxyIp:proxyPort")
http.DefaultTransport = &http.Transport{Proxy: http.ProxyURL(proxyUrl)}