Update flwr job object, client, server (#3008)

Co-authored-by: Sean Yang <seany314@gmail.com>

examples/hello-world/hello-flower/README.md

@@ -47,5 +47,5 @@ Next, we run 2 Flower clients and Flower Server in parallel using NVFlare while
 the TensorBoard metrics to the server at each iteration using NVFlare's metric streaming.
 
 ```bash
-python job.py --job_name "flwr-pt-tb" --content_dir "./flwr-pt-tb" --stream_metrics --use_client_api
+python job.py --job_name "flwr-pt-tb" --content_dir "./flwr-pt-tb" --stream_metrics
 ```

examples/hello-world/hello-flower/flwr-pt-tb/flwr_pt_tb/client.py

@@ -36,18 +36,16 @@ class FlowerClient(NumPyClient):
     def __init__(self, context: Context):
         super().__init__()
         self.writer = SummaryWriter()
-        self.set_context(context)
+        self.flwr_context = context
+
         if "step" not in context.state.metrics_records:
             self.set_step(0)
 
     def set_step(self, step: int):
-        context = self.get_context()
-        context.state = RecordSet(metrics_records={"step": MetricsRecord({"step": step})})
-        self.set_context(context)
+        self.flwr_context.state = RecordSet(metrics_records={"step": MetricsRecord({"step": step})})
 
     def get_step(self):
-        context = self.get_context()
-        return int(context.state.metrics_records["step"]["step"])
+        return int(self.flwr_context.state.metrics_records["step"]["step"])
 
     def fit(self, parameters, config):
         step = self.get_step()

examples/hello-world/hello-flower/flwr-pt-tb/flwr_pt_tb/server.py

@@ -13,8 +13,8 @@
 # limitations under the License.
 from typing import List, Tuple
 
-from flwr.common import Metrics, ndarrays_to_parameters
-from flwr.server import ServerApp, ServerConfig
+from flwr.common import Context, Metrics, ndarrays_to_parameters
+from flwr.server import ServerApp, ServerAppComponents, ServerConfig
 from flwr.server.strategy import FedAvg
 
 from .task import Net, get_weights
@@ -53,13 +53,16 @@ def weighted_average(metrics: List[Tuple[int, Metrics]]) -> Metrics:
     initial_parameters=parameters,
 )
 
-
 # Define config
 config = ServerConfig(num_rounds=3)
 
 
 # Flower ServerApp
-app = ServerApp(
-    config=config,
-    strategy=strategy,
-)
+def server_fn(context: Context):
+    return ServerAppComponents(
+        strategy=strategy,
+        config=config,
+    )
+
+
+app = ServerApp(server_fn=server_fn)

examples/hello-world/hello-flower/job.py

@@ -14,7 +14,7 @@
 
 from argparse import ArgumentParser
 
-from nvflare.app_opt.flower.flower_job import FlowerJob
+from nvflare.app_opt.flower.flower_pt_job import FlowerPyTorchJob
 from nvflare.client.api import ClientAPIType
 from nvflare.client.api_spec import CLIENT_API_TYPE_KEY
 
@@ -30,10 +30,12 @@ def main():
     args = parser.parse_args()
 
     env = {}
-    if args.use_client_api:
+    if args.stream_metrics or args.use_client_api:
+        # needs to init client api to stream metrics
+        # only external client api works with the current flower integration
         env = {CLIENT_API_TYPE_KEY: ClientAPIType.EX_PROCESS_API.value}
 
-    job = FlowerJob(
+    job = FlowerPyTorchJob(
         name=args.job_name,
         flower_content=args.content_dir,
         stream_metrics=args.stream_metrics,

nvflare/app_opt/flower/flower_job.py

@@ -19,7 +19,6 @@
 from nvflare.app_common.widgets.external_configurator import ExternalConfigurator
 from nvflare.app_common.widgets.metric_relay import MetricRelay
 from nvflare.app_common.widgets.streaming import AnalyticsReceiver
-from nvflare.app_opt.tracking.tb.tb_receiver import TBAnalyticsReceiver
 from nvflare.fuel.utils.pipe.cell_pipe import CellPipe
 from nvflare.fuel.utils.validation_utils import check_object_type
 from nvflare.job_config.api import FedJob
@@ -104,10 +103,9 @@ def __init__(
         # server side - need analytics_receiver
         if analytics_receiver:
             check_object_type("analytics_receiver", analytics_receiver, AnalyticsReceiver)
+            self.to_server(analytics_receiver, "analytics_receiver")
         else:
-            analytics_receiver = TBAnalyticsReceiver(events=["fed.analytix_log_stats"])
-
-        self.to_server(analytics_receiver, "analytics_receiver")
+            raise ValueError("Missing analytics receiver on the server side.")
 
         # client side
         # cell pipe

nvflare/app_opt/flower/flower_pt_job.py

@@ -0,0 +1,88 @@
+# Copyright (c) 2024, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from typing import List, Optional
+
+from nvflare.app_common.tie.defs import Constant
+from nvflare.app_opt.tracking.tb.tb_receiver import TBAnalyticsReceiver
+
+from .flower_job import FlowerJob
+
+
+class FlowerPyTorchJob(FlowerJob):
+    def __init__(
+        self,
+        name: str,
+        flower_content: str,
+        min_clients: int = 1,
+        mandatory_clients: Optional[List[str]] = None,
+        database: str = "",
+        server_app_args: list = None,
+        superlink_ready_timeout: float = 10.0,
+        configure_task_timeout=Constant.CONFIG_TASK_TIMEOUT,
+        start_task_timeout=Constant.START_TASK_TIMEOUT,
+        max_client_op_interval: float = Constant.MAX_CLIENT_OP_INTERVAL,
+        progress_timeout: float = Constant.WORKFLOW_PROGRESS_TIMEOUT,
+        per_msg_timeout=10.0,
+        tx_timeout=100.0,
+        client_shutdown_timeout=5.0,
+        stream_metrics=False,
+        analytics_receiver=None,
+        extra_env: dict = None,
+    ):
+        """
+        Flower Job.
+
+        Args:
+            name (str): Name of the job.
+            flower_content (str): Content for the flower job.
+            min_clients (int, optional): The minimum number of clients for the job. Defaults to 1.
+            mandatory_clients (List[str], optional): List of mandatory clients for the job. Defaults to None.
+            database (str, optional): Database string. Defaults to "".
+            server_app_args (list, optional): List of arguments to pass to the server application. Defaults to None.
+            superlink_ready_timeout (float, optional): Timeout for the superlink to be ready. Defaults to 10.0 seconds.
+            configure_task_timeout (float, optional): Timeout for configuring the task. Defaults to Constant.CONFIG_TASK_TIMEOUT.
+            start_task_timeout (float, optional): Timeout for starting the task. Defaults to Constant.START_TASK_TIMEOUT.
+            max_client_op_interval (float, optional): Maximum interval between client operations. Defaults to Constant.MAX_CLIENT_OP_INTERVAL.
+            progress_timeout (float, optional): Timeout for workflow progress. Defaults to Constant.WORKFLOW_PROGRESS_TIMEOUT.
+            per_msg_timeout (float, optional): Timeout for receiving individual messages. Defaults to 10.0 seconds.
+            tx_timeout (float, optional): Timeout for transmitting data. Defaults to 100.0 seconds.
+            client_shutdown_timeout (float, optional): Timeout for client shutdown. Defaults to 5.0 seconds.
+            stream_metrics (bool, optional): Whether to stream metrics from Flower client to Flare
+            analytics_receiver (AnalyticsReceiver, optional): the AnalyticsReceiver to use to process received metrics.
+            extra_env (dict, optional): optional extra env variables to be passed to Flower client
+        """
+        analytics_receiver = (
+            analytics_receiver if analytics_receiver else TBAnalyticsReceiver(events=["fed.analytix_log_stats"])
+        )
+
+        super().__init__(
+            name=name,
+            flower_content=flower_content,
+            min_clients=min_clients,
+            mandatory_clients=mandatory_clients,
+            database=database,
+            server_app_args=server_app_args,
+            superlink_ready_timeout=superlink_ready_timeout,
+            configure_task_timeout=configure_task_timeout,
+            start_task_timeout=start_task_timeout,
+            max_client_op_interval=max_client_op_interval,
+            progress_timeout=progress_timeout,
+            per_msg_timeout=per_msg_timeout,
+            tx_timeout=tx_timeout,
+            client_shutdown_timeout=client_shutdown_timeout,
+            stream_metrics=stream_metrics,
+            analytics_receiver=analytics_receiver,
+            extra_env=extra_env,
+        )