func main() {
configFilename := getConfigFilename()
conf, err := config.NewConfig(configFilename)
if err != nil {
log.Errorf("Trouble reading config file '%v' (%v)\n", configFilename, err)
os.Exit(exitFailure)
}
log.Printf("Using config file '%v'\n\n", configFilename)
conf.Display()
http.Handle("/", handler.NewBalancer(conf.Hosts))
http.ListenAndServe(conf.ListenAddress(), nil)
}
func (h Host) ServeHTTP(response http.ResponseWriter, request *http.Request) {
newURL, err := url.Parse(h.Hostname + request.URL.String())
if err != nil {
log.Printf("Couldn't parse url (%v): %v\n", newURL, err)
return
}
newRequest := &http.Request{
URL: newURL,
Header: request.Header,
}
intermediateResponse, err := http.DefaultClient.Do(newRequest)
if err != nil {
log.Errorf("Had a problem with a response: %v\n", err)
response.WriteHeader(http.StatusInternalServerError)
return
}
responseBody, err := ioutil.ReadAll(intermediateResponse.Body)
if err != nil {
log.Errorf("Had a problem reading response body: %v\n", err)
response.WriteHeader(http.StatusInternalServerError)
return
}
// There can be multiple values for a given header key. Here I am
// clearing any values that may pre-exist in the header and replacing
// them with the values from the response.
for key, values := range intermediateResponse.Header {
response.Header().Del(key)
for _, value := range values {
response.Header().Add(key, value)
}
}
response.WriteHeader(intermediateResponse.StatusCode)
response.Write(responseBody)
}