Routing service (#36)

routing/handler/handler.go

@@ -0,0 +1,85 @@
+package handler
+
+import (
+	"context"
+	"fmt"
+
+	"google.golang.org/protobuf/types/known/wrapperspb"
+	"googlemaps.github.io/maps"
+
+	"github.com/micro/micro/v3/service/errors"
+	"github.com/micro/micro/v3/service/logger"
+	pb "github.com/micro/services/routing/proto"
+)
+
+var (
+	ErrDownstream         = errors.InternalServerError("ROUTING_ERROR", "Unable to connect to routing provider")
+	ErrMissingOrigin      = errors.BadRequest("MISSING_ORIGIN", "Missing origin")
+	ErrMissingDestination = errors.BadRequest("MISSING_DESTINATION", "Missing destination")
+	ErrMissingLatitude    = errors.BadRequest("MISSING_LATITUDE", "Missing latitude")
+	ErrMissingLongitude   = errors.BadRequest("MISSING_LONGITUDE", "Missing longitude")
+	ErrNoRoutes           = errors.BadRequest("NO_ROUTES", "No routes found")
+)
+
+type Routing struct {
+	Maps *maps.Client
+}
+
+func (r *Routing) Route(ctx context.Context, req *pb.RouteRequest, rsp *pb.RouteResponse) error {
+	// validate the request
+	if req.Origin == nil {
+		return ErrMissingOrigin
+	}
+	if req.Destination == nil {
+		return ErrMissingDestination
+	}
+	if err := validatePoint(req.Origin); err != nil {
+		return err
+	}
+	if err := validatePoint(req.Destination); err != nil {
+		return err
+	}
+
+	// query google maps
+	routes, _, err := r.Maps.Directions(ctx, &maps.DirectionsRequest{
+		Origin: pointToString(req.Origin), Destination: pointToString(req.Destination),
+	})
+	if err != nil {
+		logger.Errorf("Error geocoding: %v. Origin: '%v', Destination: '%v'", err, pointToString(req.Origin), pointToString(req.Destination))
+		return ErrDownstream
+	}
+	if len(routes) == 0 {
+		return ErrNoRoutes
+	}
+
+	// decode the points
+	points, err := routes[0].OverviewPolyline.Decode()
+	if err != nil {
+		logger.Errorf("Error decoding polyline: %v", err)
+		return ErrDownstream
+	}
+
+	// return the result
+	rsp.Waypoints = make([]*pb.Point, len(points))
+	for i, p := range points {
+		rsp.Waypoints[i] = &pb.Point{
+			Latitude:  &wrapperspb.DoubleValue{Value: p.Lat},
+			Longitude: &wrapperspb.DoubleValue{Value: p.Lng},
+		}
+	}
+	return nil
+}
+
+func validatePoint(p *pb.Point) error {
+	if p.Latitude == nil {
+		return ErrMissingLatitude
+	}
+	if p.Longitude == nil {
+		return ErrMissingLongitude
+	}
+	return nil
+}
+
+func pointToString(p *pb.Point) string {
+	return fmt.Sprintf("%v,%v", p.Latitude.Value, p.Longitude.Value)
+}