here.go

type response struct {
	Response matrixResponse `json:"response"`
}

type matrixResponse struct {
	Route    []matrixRoute `json:"route"`
}

type matrixRoute struct {
	Summary summary `json:"summary"`
}

type summary struct {
	Distance    int `json:"distance"`
	TrafficTime int `json:"trafficTime"`
}

func HereDistanceETA() (response, error) {
    	matrixResponse := response{}
	query := fmt.Sprintf("&waypoint%v=geo!%v,%v", 0, from.Lat, from.Lon)
	query += fmt.Sprintf("&waypoint%v=geo!%v,%v", 1, to.Lat, to.Lon)
	query += "&mode=fastest;car;traffic:enabled"
	
	url := fmt.Sprintf("https://route.ls.hereapi.com/routing/7.2/calculateroute.json?apiKey=%s", h.hereAPIKey)
	url += query
	resp, err := http.Get(url)
	if err != nil {
		logrus.WithFields(logrus.Fields{
			"url":   url,
			"error": err,
		}).Error("Get here response failed")
		return durationDistancePair{}, err
	}
	if resp.StatusCode != http.StatusOK {
		return durationDistancePair{}, fmt.Errorf("Here service, status code %d", resp.StatusCode)
	}

	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return durationDistancePair{}, err
	}

	err = json.Unmarshal(body, &matrixResponse)
	if err != nil {
		return durationDistancePair{}, err
	}

	if len(matrixResponse.Response.Route) == 0 {
		return durationDistancePair{}, errors.New("Matrix response empty")
	}
	res := durationDistancePair{
		dur:            time.Duration(matrixResponse.Response.Route[0].Summary.TrafficTime) * time.Second,
		distanceMeters: matrixResponse.Response.Route[0].Summary.Distance,
	}
	return res, nil
}