Allow arbitrary args in factory mode

sanic/cli/app.py

@@ -68,6 +68,13 @@ def run(self):
         legacy_version = len(sys.argv) == 2 and sys.argv[-1] == "-v"
         parse_args = ["--version"] if legacy_version else None
 
+        if not parse_args:
+            parsed, unknown = self.parser.parse_known_args()
+            if unknown and parsed.factory:
+                for arg in unknown:
+                    if arg.startswith("--"):
+                        self.parser.add_argument(arg.split("=")[0])
+
         self.args = self.parser.parse_args(args=parse_args)
         self._precheck()
 

tests/fake/server.py

@@ -34,3 +34,12 @@ async def shutdown(app: Sanic, _):
 
 def create_app():
     return app
+
+
+def create_app_with_args(args):
+    try:
+        print(f"foo={args.foo}")
+    except AttributeError:
+        print(f"module={args.module}")
+
+    return app

tests/test_cli.py

@@ -39,16 +39,17 @@ def read_app_info(lines):
 
 
 @pytest.mark.parametrize(
-    "appname",
+    "appname,extra",
     (
-        "fake.server.app",
-        "fake.server:app",
-        "fake.server:create_app()",
-        "fake.server.create_app()",
+        ("fake.server.app", None),
+        ("fake.server:create_app", "--factory"),
+        ("fake.server.create_app()", None),
     ),
 )
-def test_server_run(appname):
+def test_server_run(appname, extra):
     command = ["sanic", appname]
+    if extra:
+        command.append(extra)
     out, err, exitcode = capture(command)
     lines = out.split(b"\n")
     firstline = lines[starting_line(lines) + 1]
@@ -57,10 +58,37 @@ def test_server_run(appname):
     assert firstline == b"Goin' Fast @ http://127.0.0.1:8000"
 
 
+def test_server_run_factory_with_args():
+    command = [
+        "sanic",
+        "fake.server.create_app_with_args",
+        "--factory",
+    ]
+    out, err, exitcode = capture(command)
+    lines = out.split(b"\n")
+
+    assert exitcode != 1, lines
+    assert b"module=fake.server.create_app_with_args" in lines
+
+
+def test_server_run_factory_with_args_arbitrary():
+    command = [
+        "sanic",
+        "fake.server.create_app_with_args",
+        "--factory",
+        "--foo=bar",
+    ]
+    out, err, exitcode = capture(command)
+    lines = out.split(b"\n")
+
+    assert exitcode != 1, lines
+    assert b"foo=bar" in lines
+
+
 def test_error_with_function_as_instance_without_factory_arg():
-    command = ["sanic", "fake.factory.run"]
+    command = ["sanic", "fake.server.create_app"]
     out, err, exitcode = capture(command)
-    assert b"try: \nsanic fake.factory.run --factory" in err
+    assert b"try: \nsanic fake.server.create_app --factory" in err
     assert exitcode != 1