Add property for optional runner

nornir/core/__init__.py

@@ -4,6 +4,7 @@
 from typing import TYPE_CHECKING, Any, Callable, Dict, Generator, List, Optional, Type
 
 from nornir.core.configuration import Config
+from nornir.core.exceptions import PluginNotRegistered
 from nornir.core.inventory import Inventory
 from nornir.core.plugins.runners import RunnerPlugin
 from nornir.core.processor import Processor, Processors
@@ -46,7 +47,7 @@ def __init__(
         self.inventory = inventory
         self.config = config or Config()
         self.processors = processors or Processors()
-        self.runner = runner
+        self._runner = runner
 
     def __enter__(self) -> "Nornir":
         return self
@@ -168,6 +169,13 @@ def close_connections_task(task):
 
         self.run(task=close_connections_task, on_good=on_good, on_failed=on_failed)
 
+    @property
+    def runner(self) -> RunnerPlugin:
+        if self._runner:
+            return self._runner
+
+        raise PluginNotRegistered("Runner plugin not registered")
+
     @classmethod
     def get_validators(cls) -> Generator[Callable[["Nornir"], "Nornir"], None, None]:
         yield cls.validate

setup.cfg

@@ -48,7 +48,6 @@ warn_redundant_casts = True
 [mypy-nornir.core]
 disallow_untyped_defs = False
 disallow_incomplete_defs = False
-strict_optional = False
 
 [mypy-tests.*]
 ignore_errors = True