Add demo for vertical federated learning (#9103)

demo/nvflare/vertical/custom/controller.py

@@ -0,0 +1,68 @@
+"""
+Example of training controller with NVFlare
+===========================================
+"""
+import multiprocessing
+
+from nvflare.apis.client import Client
+from nvflare.apis.fl_context import FLContext
+from nvflare.apis.impl.controller import Controller, Task
+from nvflare.apis.shareable import Shareable
+from nvflare.apis.signal import Signal
+from trainer import SupportedTasks
+
+import xgboost.federated
+
+
+class XGBoostController(Controller):
+    def __init__(self, port: int, world_size: int, server_key_path: str,
+                 server_cert_path: str, client_cert_path: str):
+        """Controller for federated XGBoost.
+
+        Args:
+            port: the port for the gRPC server to listen on.
+            world_size: the number of sites.
+            server_key_path: the path to the server key file.
+            server_cert_path: the path to the server certificate file.
+            client_cert_path: the path to the client certificate file.
+        """
+        super().__init__()
+        self._port = port
+        self._world_size = world_size
+        self._server_key_path = server_key_path
+        self._server_cert_path = server_cert_path
+        self._client_cert_path = client_cert_path
+        self._server = None
+
+    def start_controller(self, fl_ctx: FLContext):
+        self._server = multiprocessing.Process(
+            target=xgboost.federated.run_federated_server,
+            args=(self._port, self._world_size, self._server_key_path,
+                  self._server_cert_path, self._client_cert_path))
+        self._server.start()
+
+    def stop_controller(self, fl_ctx: FLContext):
+        if self._server:
+            self._server.terminate()
+
+    def process_result_of_unknown_task(self, client: Client, task_name: str,
+                                       client_task_id: str, result: Shareable,
+                                       fl_ctx: FLContext):
+        self.log_warning(fl_ctx, f"Unknown task: {task_name} from client {client.name}.")
+
+    def control_flow(self, abort_signal: Signal, fl_ctx: FLContext):
+        self.log_info(fl_ctx, "XGBoost training control flow started.")
+        if abort_signal.triggered:
+            return
+        task = Task(name=SupportedTasks.TRAIN, data=Shareable())
+        self.broadcast_and_wait(
+            task=task,
+            min_responses=self._world_size,
+            fl_ctx=fl_ctx,
+            wait_time_after_min_received=1,
+            abort_signal=abort_signal,
+        )
+        if abort_signal.triggered:
+            return
+
+        self.log_info(fl_ctx, "XGBoost training control flow finished.")