Support customizing map name (#3)

* Add `-map` option flag to correspond to map layer name in renderd.conf

* Add `map_name` value to `data_dir` tile path

* Update `README.md`

README.md

@@ -40,6 +40,8 @@ If you prefer to run the binary directly you have the following options:
 Usage of /tmp/go-build2340306719/b001/exe/osm-tileserver:
   -data string
         Path to directory containing tiles (default "./data")
+  -map string
+        Name of map. This value is also used to determine the metatile subdirectory (default "ajt")
   -port string
         Listening port (default ":8080")
   -renderd-timeout int
@@ -58,7 +60,7 @@ Usage of /tmp/go-build2340306719/b001/exe/osm-tileserver:
 2. Follow the [breadcrumbs](https://github.com/Overv/openstreetmap-tile-server/issues/15) about how to pregenerate tiles for the desired area and zoom-level.
     1. Get a shell in the container: `docker exec -it $CONTAINER_NAME bash`
     2. Download a script that makes it easier to specify GPS coordinates: `curl -o render_list_geo.pl https://raw.githubusercontent.com/alx77/render_list_geo.pl/master/render_list_geo.pl`
-    3. Pregenerate the tiles to your liking: `perl ./render_list_geo.pl -m ajt  -n 3 -z 6 -Z 16 -x 2.5 -X 6.5 -y 49.4 -Y 51.6`
+    3. Pregenerate the tiles to your liking: `perl ./render_list_geo.pl -m ajt -n 3 -z 6 -Z 16 -x 2.5 -X 6.5 -y 49.4 -Y 51.6`
 3. Cheers, you now have tiles in the `$YOUR_TILE_FOLDER`.
 
 ## Performance
@@ -102,5 +104,5 @@ Percentage of the requests served within a certain time (ms)
  100%      9 (longest request)
 ```
 
-This benchmark doesn't access the disk, as the tile has obviously been cached in memory. 
+This benchmark doesn't access the disk, as the tile has obviously been cached in memory.
 Anyways it should give you an indication of whether this is fast enough for your use-case.

main.go

@@ -31,7 +31,7 @@ import (
  * along with this program; If not, see http://www.gnu.org/licenses/.
  */
 
-func findPath(baseDir string, z, x, y uint32) (metaPath string, offset uint32) {
+func findPath(baseDir, mapName string, z, x, y uint32) (metaPath string, offset uint32) {
 	var mask uint32
 	var hash [5]byte
 
@@ -47,7 +47,7 @@ func findPath(baseDir string, z, x, y uint32) (metaPath string, offset uint32) {
 		x >>= 4
 		y >>= 4
 	}
-	metaPath = fmt.Sprintf("%s/%d/%d/%d/%d/%d/%d.meta", baseDir, z, hash[4], hash[3], hash[2], hash[1], hash[0])
+	metaPath = fmt.Sprintf("%s/%s/%d/%d/%d/%d/%d/%d.meta", baseDir, mapName, z, hash[4], hash[3], hash[2], hash[1], hash[0])
 	return
 }
 
@@ -122,23 +122,23 @@ func parsePath(path string) (z, x, y uint32, err error) {
 	return
 }
 
-func handleRequest(resp http.ResponseWriter, req *http.Request, data_dir *string, renderd_sock_path string, renderd_timeout time.Duration) {
+func handleRequest(resp http.ResponseWriter, req *http.Request, data_dir, map_name, renderd_sock_path string, renderd_timeout time.Duration) {
 	z, x, y, err := parsePath(req.URL.Path)
 	if err != nil {
 		resp.WriteHeader(http.StatusBadRequest)
 		resp.Write([]byte(err.Error()))
 		return
 	}
 	resp.Header().Add("Content-Type", "image/png")
-	metatile_path, metatile_offset := findPath(*data_dir, z, x, y)
+	metatile_path, metatile_offset := findPath(data_dir, map_name, z, x, y)
 	fileInfo, statErr := os.Stat(metatile_path)
 	if statErr != nil {
 		if errors.Is(statErr, os.ErrNotExist) {
 			if len(renderd_sock_path) == 0 {
 				resp.WriteHeader(http.StatusNotFound)
 				return
 			}
-			renderErr := requestRender(x, y, z, renderd_sock_path, renderd_timeout)
+			renderErr := requestRender(x, y, z, map_name, renderd_sock_path, renderd_timeout)
 			if renderErr != nil {
 				fmt.Printf("Could not generate tile for coordinates %d, %d, %d (x,y,z). '%s'\n", x, y, z, renderErr)
 				// Not returning as we are hoping and praying that rendering did nonetheless produce a file
@@ -169,6 +169,7 @@ func main() {
 	static_dir := flag.String("static", "./static/", "Path to static file directory")
 	renderd_sock_path := flag.String("socket", "/var/run/renderd/renderd.sock", "Path to renderd socket. Set to '' to disable rendering")
 	renderd_timeout := flag.Int("renderd-timeout", 60, "time in seconds to wait for renderd before returning an error to the client. Set negative to disable")
+	map_name := flag.String("map", "ajt", "Name of map. This value is also used to determine the metatile subdirectory")
 	var renderd_timeout_duration time.Duration = time.Duration(*renderd_timeout) * time.Second
 	flag.Parse()
 	http.HandleFunc("/tile/", func(w http.ResponseWriter, r *http.Request) {
@@ -177,7 +178,7 @@ func main() {
 			w.Write([]byte("Only GET requests allowed"))
 			return
 		}
-		handleRequest(w, r, data_dir, *renderd_sock_path, renderd_timeout_duration)
+		handleRequest(w, r, *data_dir, *map_name, *renderd_sock_path, renderd_timeout_duration)
 	})
 	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		http.FileServer(http.Dir(*static_dir)).ServeHTTP(w, r)

renderer.go

@@ -22,7 +22,7 @@ type Request struct {
 	Map         [44]byte
 }
 
-func requestRender(x, y, z uint32, renderd_sock_path string, renderd_timeout time.Duration) error {
+func requestRender(x, y, z uint32, map_name, renderd_sock_path string, renderd_timeout time.Duration) error {
 	c, err := net.Dial("unix", renderd_sock_path)
 	if err != nil {
 		return err
@@ -38,7 +38,7 @@ func requestRender(x, y, z uint32, renderd_sock_path string, renderd_timeout tim
 		Y:           y,
 		Z:           z,
 	}
-	copy(request.Map[:], []byte("ajt"))
+	copy(request.Map[:], []byte(map_name))
 	if err := binary.Write(c, binary.LittleEndian, request); err != nil {
 		return err
 	}