routing-service/valhalla.go

package routing

import (
	"bytes"
	"errors"
	"io/ioutil"
	"net/http"
	"time"

	"git.coopgo.io/coopgo-platform/routing-service/encoding/polylines"
	"git.coopgo.io/coopgo-platform/routing-service/proto/valhalla"
	"github.com/paulmach/orb"
	"github.com/rs/zerolog/log"
	"google.golang.org/protobuf/proto"
)

type ValhallaRouting struct {
	BaseURL string
}

func NewValhallaRouting(baseURL string) (*ValhallaRouting, error) {
	return &ValhallaRouting{
		BaseURL: baseURL,
	}, nil
}

func (v *ValhallaRouting) Route(locations []orb.Point) (route *Route, err error) {

	valhalla_locations := []*valhalla.Location{}

	for _, loc := range locations {
		valhalla_locations = append(valhalla_locations, &valhalla.Location{
			Ll: &valhalla.LatLng{
				HasLat: &valhalla.LatLng_Lat{Lat: loc.Lat()},
				HasLng: &valhalla.LatLng_Lng{Lng: loc.Lon()},
			},
		})
	}

	request := &valhalla.Api{
		Options: &valhalla.Options{
			Action:      valhalla.Options_route,
			Locations:   valhalla_locations,
			CostingType: valhalla.Costing_auto_,
			Format:      valhalla.Options_pbf,
		},
	}

	resp, err := v.protocolBufferRequest(request, "route")
	if err != nil {
		log.Error().Err(err).Msg("pb request to valhalla error")
		return nil, err
	}

	if resp.Directions == nil || resp.Directions.Routes == nil || len(resp.Directions.Routes) < 1 {
		return nil, errors.New("no routes returned by valhalla")
	}

	decodedLinestring := orb.LineString{}

	legs := []RouteLeg{}

	for _, leg := range resp.Directions.Routes[0].Legs {
		shape := leg.Shape
		decodedShape := polylines.Decode(&shape, 6)
		decodedLinestring = append(decodedLinestring, decodedShape...)

		routeLeg := RouteLeg{
			Distance: float64(leg.Summary.Length),
			Duration: time.Duration(leg.Summary.Time) * time.Second,
			Polyline: polylines.Encode(decodedShape, 5),
		}

		legs = append(legs, routeLeg)
	}

	return &Route{
		Summary: RouteSummary{
			Polyline: polylines.Encode(decodedLinestring, 5),
		},
		Legs: legs,
	}, nil
}

func (v *ValhallaRouting) protocolBufferRequest(api *valhalla.Api, path string) (*valhalla.Api, error) {
	data, err := proto.Marshal(api)
	if err != nil {
		return nil, err
	}

	req, err := http.NewRequest(http.MethodGet, v.BaseURL+path, bytes.NewBuffer(data))
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", "application/x-protobuf")

	client := http.Client{}
	resp, err := client.Do(req)
	//resp, err := http.Post(v.BaseURL+path, "application/x-protobuf", bytes.NewBuffer(data))
	if err != nil {
		return nil, err
	}

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

	response := valhalla.Api{}
	err = proto.Unmarshal(body, &response)
	if err != nil {
		return nil, err
	}

	return &response, nil
}