go-error-handling

error.go

body, err := ioutil.ReadAll(res.Body)
if err != nil {
    return forecast, err  // return an error and let the caller handle it
}
err = json.Unmarshal(body, &forecast)
if err != nil {
    log.Fatalf("error unmarshaling body %s: %s", url, err.Error())
}
forecast.Expires, err = http.ParseTime(res.Header.Get("Expires"))
if err != nil {
    panic("could not parse expires header")
}