fix: update nitric server connection refused errors (#144)

Improves the description of the errors and removes a reference to the v0 `nitric start` command
set correct min python version

Co-authored-by: Ryan Cartwright <39504851+HomelessDinosaur@users.noreply.github.com>

Author: jyecusch

.python-version

@@ -1 +1 @@
-3.10.12
+3.11.0

README.md

@@ -22,7 +22,7 @@
   <a href="https://nitric.io/chat"><img alt="Discord" src="https://img.shields.io/discord/955259353043173427?label=discord&style=for-the-badge"></a>
 </p>
 
-The Python SDK supports the use of the [Nitric](https://nitric.io) framework with Python 3.10+. For more information check out the main [Nitric repo](https://github.com/nitrictech/nitric).
+The Python SDK supports the use of the [Nitric](https://nitric.io) framework with Python 3.11+. For more information check out the main [Nitric repo](https://github.com/nitrictech/nitric).
 
 Python SDKs provide an infrastructure-from-code style that lets you define resources in code. You can also write the functions that support the logic behind APIs, subscribers and schedules.
 

nitric/application.py

@@ -56,10 +56,10 @@ def _create_resource(cls, resource: Type[BT], name: str, *args: Any, **kwargs: A
                 cls._cache[resource_type][name] = resource.make(name, *args, **kwargs)  # type: ignore
 
             return cls._cache[resource_type][name]
-        except ConnectionRefusedError:
+        except ConnectionRefusedError as cre:
             raise NitricUnavailableException(
-                'Unable to connect to a nitric server! If you\'re running locally make sure to run "nitric start"'
-            ) from None
+                "The nitric server may not be running or the host/port is inaccessible"
+            ) from cre
 
     @classmethod
     def run(cls) -> None:
@@ -78,7 +78,7 @@ def run(cls) -> None:
         except KeyboardInterrupt:
 
             print("\nexiting")
-        except ConnectionRefusedError:
+        except ConnectionRefusedError as cre:
             raise NitricUnavailableException(
-                'Unable to connect to a nitric server! If you\'re running locally make sure to run "nitric start"'
-            ) from None
+                'If you\'re running locally use "nitric start" or "nitric run" to start your application'
+            ) from cre

nitric/exception.py

@@ -153,7 +153,8 @@ class NitricResourceException(Exception):
 class NitricUnavailableException(Exception):
     """Unable to connect to a nitric server."""
 
-    pass
+    def __init__(self, message: str):
+        super().__init__("Unable to connect to nitric server." + (" " + message if message else ""))
 
 
 def exception_from_grpc_error(error: GRPCError):

tests/test_application.py

@@ -96,7 +96,7 @@ def test_run_with_connection_refused(self):
                     application.run()
                     pytest.fail()
                 except NitricUnavailableException as e:
-                    assert str(e).startswith("Unable to connect to a nitric server!")
+                    assert str(e).startswith("Unable to connect to nitric server")
 
                 mock_running_loop.assert_called_once()
                 mock_event_loop.assert_not_called()