Fix reloader on OSX py38 and Windows (#1827)

* Fix watchdog reload worker repeatedly if there are multiple changed files

* Simplify autoreloader, don't need multiprocessing.Process. Now works on OSX py38.

* Allow autoreloader with multiple workers and run it earlier.

* This works OK on Windows too.

* I don't see how cwd could be different here.

* app.run and app.create_server argument fixup.

* Add test for auto_reload (coverage not working unfortunately).

* Reloader cleanup, don't use external kill commands and exit normally.

* Strip newlines on test output (Windows-compat).

* Report failures in test_auto_reload to avoid timeouts.

* Use different test server ports to avoid binding problems on Windows.

* Fix previous commit

* Listen on same port after reload.

* Show Goin' Fast banner on reloads.

* More robust testing, also -m sanic.

* Add a timeout to terminate process

* Try a workaround for tmpdir deletion on Windows.

* Join process also on error (context manager doesn't).

* Cleaner autoreloader termination on Windows.

* Remove unused code.

* Rename test.

* Longer timeout on test exit.

Co-authored-by: Hùng X. Lê <lexhung@gmail.com>
Co-authored-by: L. Kärkkäinen <tronic@users.noreply.github.com>
Co-authored-by: Adam Hopkins <admhpkns@gmail.com>

sanic/app.py

@@ -1058,7 +1058,9 @@ class Sanic:
         self,
         host: Optional[str] = None,
         port: Optional[int] = None,
+        *,
         debug: bool = False,
+        auto_reload: Optional[bool] = None,
         ssl: Union[dict, SSLContext, None] = None,
         sock: Optional[socket] = None,
         workers: int = 1,
@@ -1067,7 +1069,7 @@ class Sanic:
         stop_event: Any = None,
         register_sys_signals: bool = True,
         access_log: Optional[bool] = None,
-        **kwargs: Any,
+        loop: None = None,
     ) -> None:
         """Run the HTTP Server and listen until keyboard interrupt or term
         signal. On termination, drain connections before closing.
@@ -1078,6 +1080,9 @@ class Sanic:
         :type port: int
         :param debug: Enables debug output (slows server)
         :type debug: bool
+        :param auto_reload: Reload app whenever its source code is changed.
+                            Enabled by default in debug mode.
+        :type auto_relaod: bool
         :param ssl: SSLContext, or location of certificate and key
                     for SSL encryption of worker(s)
         :type ssl: SSLContext or dict
@@ -1099,7 +1104,7 @@ class Sanic:
         :type access_log: bool
         :return: Nothing
         """
-        if "loop" in kwargs:
+        if loop is not None:
             raise TypeError(
                 "loop is not a valid argument. To use an existing loop, "
                 "change to create_server().\nSee more: "
@@ -1107,13 +1112,9 @@ class Sanic:
                 "#asynchronous-support"
             )
 
-        # Default auto_reload to false
-        auto_reload = False
-        # If debug is set, default it to true (unless on windows)
-        if debug and os.name == "posix":
-            auto_reload = True
-        # Allow for overriding either of the defaults
-        auto_reload = kwargs.get("auto_reload", auto_reload)
+        if auto_reload or auto_reload is None and debug:
+            if os.environ.get("SANIC_SERVER_RUNNING") != "true":
+                return reloader_helpers.watchdog(1.0)
 
         if sock is None:
             host, port = host or "127.0.0.1", port or 8000
@@ -1156,18 +1157,7 @@ class Sanic:
                 )
                 workers = 1
             if workers == 1:
-                if auto_reload and os.name != "posix":
-                    # This condition must be removed after implementing
-                    # auto reloader for other operating systems.
-                    raise NotImplementedError
-
-                if (
-                    auto_reload
-                    and os.environ.get("SANIC_SERVER_RUNNING") != "true"
-                ):
-                    reloader_helpers.watchdog(2)
-                else:
-                    serve(**server_settings)
+                serve(**server_settings)
             else:
                 serve_multiple(server_settings, workers)
         except BaseException:
@@ -1189,6 +1179,7 @@ class Sanic:
         self,
         host: Optional[str] = None,
         port: Optional[int] = None,
+        *,
         debug: bool = False,
         ssl: Union[dict, SSLContext, None] = None,
         sock: Optional[socket] = None,
@@ -1413,7 +1404,7 @@ class Sanic:
             server_settings["run_async"] = True
 
         # Serve
-        if host and port and os.environ.get("SANIC_SERVER_RUNNING") != "true":
+        if host and port:
             proto = "http"
             if ssl is not None:
                 proto = "https"