App 2.39.0, server 2.7.0: Grid with map

A new Overview style: the Grid over the roads round the car from
OpenStreetMap, drawn in the floor's perspective, heading up, the bigger
roads glowing brighter, the car as a chevron.

Server: POST /v1/map/roads {z:14,x,y} fetches a tile's drivable roads
from Overpass (OVERPASS_URL; one request at a time, at least a second
apart), simplifies them to tile-local points in four classes, caches
them for 30 days and never logs the tile.

App: MapRoads keeps the 3x3 tiles round the car from its own cache or
the server; GPS only while the style is shown; bearing from the GPS or
from successive positions. Without GPS, server or roads the plain floor
says why. OSM attribution on screen and in LICENSE.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LhzAVaUyqcw5PkGjz4mWW6

server/main.go

@@ -34,6 +34,7 @@ type config struct {
 	forgeURL     string
 	forgeRepo    string
 	forgeToken   string
+	overpassURL  string
 }
 
 // loadConfig reads the environment and fails closed: a missing InfluxDB setting or a
@@ -51,6 +52,7 @@ func loadConfig(getenv func(string) string) (config, error) {
 		forgeURL:     getenv("FORGE_URL"),
 		forgeRepo:    getenv("FORGE_REPO"),
 		forgeToken:   getenv("FORGE_TOKEN"),
+		overpassURL:  getenv("OVERPASS_URL"),
 	}
 	if c.listenAddr == "" {
 		c.listenAddr = ":8080"
@@ -73,6 +75,18 @@ func loadConfig(getenv func(string) string) (config, error) {
 	if c.forgeURL != "" && !strings.HasPrefix(c.forgeURL, "https://") {
 		return config{}, errors.New("FORGE_URL must be an https URL")
 	}
+	// The map's roads come from an Overpass API: the public one unless another is named, none
+	// with "off". Only https, like the forge.
+	switch c.overpassURL {
+	case "":
+		c.overpassURL = DefaultOverpassURL
+	case "off":
+		c.overpassURL = ""
+	default:
+		if !strings.HasPrefix(c.overpassURL, "https://") {
+			return config{}, errors.New("OVERPASS_URL must be an https URL or \"off\"")
+		}
+	}
 	if c.approvalPass != "" && len(c.approvalPass) < minApprovalPasswordLength {
 		return config{}, fmt.Errorf("APPROVAL_PASSWORD must be at least %d characters", minApprovalPasswordLength)
 	}
@@ -102,6 +116,9 @@ func main() {
 	releases := &Releases{ForgeURL: cfg.forgeURL, Repo: cfg.forgeRepo, Token: cfg.forgeToken}
 	api := &API{Store: store, IngestToken: cfg.ingestToken, Pairing: pairing, Handoff: NewHandoff(),
 		Releases: releases, PublicURL: cfg.publicURL}
+	if cfg.overpassURL != "" {
+		api.Maps = NewMaps(cfg.overpassURL, mapUserAgent)
+	}
 
 	srv := &http.Server{
 		Addr:              cfg.listenAddr,
@@ -116,7 +133,8 @@ func main() {
 	defer stop()
 	go func() {
 		slog.Info("listening", "addr", cfg.listenAddr, "bucket", cfg.influxBucket,
-			"pairing", pairing.Enabled(), "pairedDevices", len(devices), "appUpdates", releases.enabled())
+			"pairing", pairing.Enabled(), "pairedDevices", len(devices), "appUpdates", releases.enabled(),
+			"maps", api.Maps != nil)
 		if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
 			slog.Error("server failed", "error", err)
 			os.Exit(1)