Add possibility to include router via string

aiogram/dispatcher/router.py

@@ -1,8 +1,9 @@
 from __future__ import annotations
 
-from typing import Any, Dict, List, Optional
+from typing import Any, Dict, List, Optional, Union
 
 from ..api.types import Chat, Update, User
+from ..utils.imports import import_module
 from .event.observer import EventObserver, SkipHandler, TelegramEventObserver
 from .filters import BUILTIN_FILTERS
 
@@ -76,7 +77,13 @@ class Router:
 
         self._parent_router = router
 
-    def include_router(self, router: Router) -> Router:
+    def include_router(self, router: Union[Router, str]) -> Router:
+        if isinstance(router, str):
+            router = import_module(router)
+        if not isinstance(router, Router):
+            raise ValueError(
+                f"router should be instance of Router not {type(router).__class__.__name__}"
+            )
         router.parent_router = self
         self.sub_routers.append(router)
         return router

aiogram/utils/imports.py

@@ -0,0 +1,23 @@
+import importlib
+from typing import Any
+
+
+def import_module(target: str) -> Any:
+    if not isinstance(target, str):
+        raise ValueError(f"Target should be string not {type(target).__class__.__name__}")
+
+    module_name, _, attr_name = target.partition(":")
+    if not module_name or not attr_name:
+        raise ValueError(f'Import string "{target}" must be in format "<module>:<attribute>"')
+
+    try:
+        module = importlib.import_module(module_name)
+    except ImportError:
+        raise ValueError(f'Could not import module "{module_name}".')
+
+    try:
+        attribute = getattr(module, attr_name)
+    except AttributeError:
+        raise ValueError(f'Module "{module_name}" has no attribute "{attr_name}"')
+
+    return attribute