feat(framework) Add internal flwr-clientapp command

pyproject.toml

@@ -59,6 +59,7 @@ flower-supernode = "flwr.client:run_supernode"
 flower-client-app = "flwr.client:run_client_app"
 flower-server-app = "flwr.server:run_server_app"
 flower-simulation = "flwr.simulation.run_simulation:run_simulation_from_cli"
+flower-exec-client-app = "flwr.client.supernode:exec_client_app"
 
 [tool.poetry.dependencies]
 python = "^3.8"

src/py/flwr/client/supernode/__init__.py

@@ -15,10 +15,12 @@
 """Flower SuperNode."""
 
 
+from .app import exec_client_app as exec_client_app
 from .app import run_client_app as run_client_app
 from .app import run_supernode as run_supernode
 
 __all__ = [
+    "exec_client_app",
     "run_client_app",
     "run_supernode",
 ]

src/py/flwr/client/supernode/app.py

@@ -119,6 +119,17 @@ def run_client_app() -> None:
     register_exit_handlers(event_type=EventType.RUN_CLIENT_APP_LEAVE)
 
 
+def exec_client_app() -> None:
+    """Run process-isolated Flower client app."""
+    log(INFO, "Starting Flower ClientApp")
+
+    event(EventType.RUN_CLIENT_APP_ENTER)
+
+    # args = _parse_args_exec_client_app().parse_args()
+
+    register_exit_handlers(event_type=EventType.RUN_CLIENT_APP_LEAVE)
+
+
 def _warn_deprecated_server_arg(args: argparse.Namespace) -> None:
     """Warn about the deprecated argument `--server`."""
     if args.server != ADDRESS_FLEET_API_GRPC_RERE:
@@ -275,6 +286,13 @@ def _parse_args_run_supernode() -> argparse.ArgumentParser:
         - `$HOME/.flwr/` in all other cases
     """,
     )
+    parser.add_argument(
+        "--isolate",
+        action="store_true",
+        help="Run the ClientApp in an isolated process from the SuperNode."
+        "In this mode, the ClientApp and SuperNode communicate via gRPC."
+        "By default, both SuperNode and ClientApp run in the same process.",
+    )
 
     return parser
 
@@ -294,6 +312,23 @@ def _parse_args_run_client_app() -> argparse.ArgumentParser:
     return parser
 
 
+def _parse_args_exec_client_app() -> argparse.ArgumentParser:
+    """Parse exec-client-app command line arguments."""
+    parser = argparse.ArgumentParser(
+        description="Run a Flower client app",
+    )
+    parser.add_argument(
+        "--address",
+        help="Address of SuperNode",
+    )
+    parser.add_argument(
+        "--token",
+        help="Unique token generated by SuperNode for each client app execution",
+    )
+
+    return parser
+
+
 def _parse_args_common(parser: argparse.ArgumentParser) -> None:
     parser.add_argument(
         "--insecure",