refactor: abstract traefik router labels and dynamic config

modules/apps/traefik/default.nix

@@ -12,6 +12,11 @@ in {
       default = "traefik";
       description = "The name of the shared network to connect the container to.";
     };
+    dynamicConfigOptions = lib.mkOption {
+      type = lib.types.attrs;
+      default = {};
+      description = "Dynamic configuration options to write to file and mount into Traefik.";
+    };
   };
 
   config = lib.mkIf cfg.enable {
@@ -35,6 +40,7 @@ in {
       ];
       extraOptions = [
         "--network=${cfg.sharedNetworkName}"
+        "--add-host=host.docker.internal:host-gateway"
       ];
       environmentFiles = [
         /home/admin/.cloudflare.secret
@@ -46,6 +52,10 @@ in {
         "--providers.docker=true"
         "--providers.docker.exposedByDefault=false"
 
+        # Add File provider
+        "--providers.file.filename=/etc/traefik/dynamic_conf.yml"
+        "--providers.file.watch=true"
+
         # Add web entrypoint
         "--entrypoints.web.address=:80/tcp"
         "--entrypoints.web.http.redirections.entrypoint.to=websecure"
@@ -65,10 +75,14 @@ in {
         "--certificatesresolvers.letsencrypt.acme.email=tibo.depeuter@telenet.be"
         "--certificatesresolvers.letsencrypt.acme.storage=/letsencrypt/acme.json"
       ];
-      volumes = [
+      volumes = let
+        dynamicConfFormat = pkgs.formats.yaml { };
+        dynamicConfFile = dynamicConfFormat.generate "traefik-dynamic-conf.yml" cfg.dynamicConfigOptions;
+      in [
         "letsencryp:/letsencrypt"
 
         "/var/run/docker.sock:/var/run/docker.sock:ro"
+        "${dynamicConfFile}:/etc/traefik/dynamic_conf.yml:ro"
       ];
       labels = {
         "traefik.enable" = "true";