refactor: abstract traefik router labels and dynamic config

modules/common/traefik.nix

@@ -0,0 +1,65 @@
+{ config, lib, ... }:
+
+let
+  proxyNet = config.homelab.apps.traefik.sharedNetworkName;
+in {
+  options.homelab.traefikRouters = lib.mkOption {
+    type = lib.types.attrsOf (lib.types.submodule {
+      options = {
+        rule = lib.mkOption {
+          type = lib.types.str;
+          description = "The Traefik router rule, e.g. Host(`example.com`)";
+        };
+        port = lib.mkOption {
+          type = lib.types.int;
+          description = "The port the service listens on";
+        };
+        middlewares = lib.mkOption {
+          type = lib.types.listOf lib.types.str;
+          default = [];
+          description = "Middlewares to apply";
+        };
+        tls = lib.mkOption {
+          type = lib.types.bool;
+          default = false;
+          description = "Whether to enable TLS";
+        };
+        entryPoints = lib.mkOption {
+          type = lib.types.listOf lib.types.str;
+          default = [];
+          description = "Entrypoints to use";
+        };
+        extraLabels = lib.mkOption {
+          type = lib.types.attrsOf lib.types.str;
+          default = {};
+          description = "Extra labels to apply";
+        };
+      };
+    });
+    default = {};
+    description = "Declarative Traefik router configuration";
+  };
+
+  config = {
+    # Generate labels for containers based on homelab.traefikRouters
+    # This assumes that the name in homelab.traefikRouters matches the container name.
+    virtualisation.oci-containers.containers = lib.mapAttrs (name: router: {
+      labels = {
+        "traefik.enable" = "true";
+        "traefik.docker.network" = proxyNet;
+        "traefik.http.routers.${name}.rule" = router.rule;
+        "traefik.http.services.${name}.loadbalancer.server.port" = toString router.port;
+      }
+      // lib.optionalAttrs (router.middlewares != []) {
+        "traefik.http.routers.${name}.middlewares" = builtins.concatStringsSep "," router.middlewares;
+      }
+      // lib.optionalAttrs router.tls {
+        "traefik.http.routers.${name}.tls" = "true";
+      }
+      // lib.optionalAttrs (router.entryPoints != []) {
+        "traefik.http.routers.${name}.entryPoints" = builtins.concatStringsSep "," router.entryPoints;
+      }
+      // router.extraLabels;
+    }) config.homelab.traefikRouters;
+  };
+}