Add a command line tool to generate OAS in a file

aiohttp_pydantic/oas/cmd.py

@@ -0,0 +1,45 @@
+import argparse
+import importlib
+import json
+
+from .view import generate_oas
+
+
+def application_type(value):
+    """
+    Return aiohttp application defined in the value.
+    """
+    try:
+        module_name, app_name = value.split(":")
+    except ValueError:
+        module_name, app_name = value, "app"
+
+    module = importlib.import_module(module_name)
+    try:
+        if app_name.endswith("()"):
+            app_name = app_name.strip("()")
+            factory_app = getattr(module, app_name)
+            return factory_app()
+        return getattr(module, app_name)
+
+    except AttributeError as error:
+        raise argparse.ArgumentTypeError(error) from error
+
+
+def setup(parser: argparse.ArgumentParser):
+    parser.add_argument(
+        "apps",
+        metavar="APP",
+        type=application_type,
+        nargs="*",
+        help="The name of the module containing the asyncio.web.Application."
+        " By default the variable named 'app' is loaded but you can define"
+        " an other variable name ending the name of module with : characters"
+        " and the name of variable. Example: my_package.my_module:my_app",
+    )
+
+    parser.set_defaults(func=show_oas)
+
+
+def show_oas(args: argparse.Namespace):
+    print(json.dumps(generate_oas(args.apps), sort_keys=True, indent=4))